Upconversion nanoparticles@Carbon Dots@Meso-SiO2 Sandwiched

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Upconversion nanoparticles@Carbon Dots@Meso-SiO2 Sandwiched Core-shell Nanohybrids with Tunable DualMode Luminescence for 3D Anti-Counterfeiting Barcodes Haihu Tan, Guo Gong, Shaowen Xie, Ya Song, Changfan Zhang, Na Li, Dong Zhang, Lijian Xu, Jianxiong Xu, and Jie Zheng Langmuir, Just Accepted Manuscript • DOI: 10.1021/acs.langmuir.9b01919 • Publication Date (Web): 31 Jul 2019 Downloaded from pubs.acs.org on July 31, 2019

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Upconversion nanoparticles@Carbon Dots@Meso-SiO2 Sandwiched Coreshell Nanohybrids with Tunable Dual-Mode Luminescence for 3D AntiCounterfeiting Barcodes Haihu Tan,a,b Guo Gong,a,b Shaowen Xie,a,b Ya Song,a Changfan Zhang,a Na Li,a,b,c Dong Zhang, d Lijian Xu,a,b,c* Jianxiong Xu,a,b,c and Jie Zhengd aHunan

Key Laboratory of Biomedical Nanomaterials and Devices, College of Life

Sciences and Chemistry, Hunan University of Technology, Zhuzhou 412007, P. R. China bNational

& Local Joint Engineering Research Center of Advanced Packaging Materials,

Developing Technology, Hunan University of Technology, Zhuzhou, 412007, PR China cSchool

of Materials Science and Energy Engineering, Foshan University, Foshan,

528000, P. R. China dDepartment

of Chemical and Biomolecular Engineering, The University of Akron,

Akron, OH, 44325, USA * To whom correspondence should be addressed. E-mail: (L.X.) [email protected]

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Abstract: Development of advanced fluorescent materials for constructing secure and unclonable encryption is highly demanded, but has proved to be a great challenge for anti-counterfeiting applications. In this work, we proposed and synthesized a new type of upconversion nanoparticles@carbon dots@meso-SiO2 nanohybrids by integrating two fluorescent materials of lanthanide-doped NaYF4 upconversion nanoparticles (UCNPs) and carbon dots (CDs) into mesoporous silica (mSiO2) to produce a novel sandwich-like core-shell structure and a dual-mode fluorescence from UCNPs and CDs. By tailoring the UCNPs core of different upconversion luminescence, all three kinds of dual-mode luminescent UCNPs@CDs@mSiO2 nanohybrids exhibited typical RGB upconversion luminescence under a 980 nm laser and blue downconversion 2 ACS Paragon Plus Environment

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luminescence under a 365 nm UV light. Due to strong hydrophilic nature of the nanohybrids, they can be further fabricated into environmental benign luminescent inks for creating highly secured, fluorescent-based, three-dimensional anti-counterfeiting barcodes via inkjet printing. The resultant UCNPs@CDs@mSiO2 inks with dual-mode and tunable luminescence nature endow the inkjet-printing barcodes with an extremely high encoding capacity and high security. Such dual-mode fluorescent inks and barcodes are simple to fabricate, easy to view, efficient for coding, and difficult to clone, thus employing them as promising nanomaterials for anti-counterfeiting applications. Keywords: core-shell nanoparticles, lanthanide-doped NaYF4, carbon dots, dual-mode fluorescence, barcodes, anti-counterfeiting 1. Introduction The fast growth of a counterfeiting market for almost all commodities including banknotes, fuels, medicine, coatings, and labels has become a serious, global, longstanding problem, which causes a huge loss of global economy, human health, and scientific development.1-4 Hence, a wide variety of anti-counterfeiting techniques and materials have been developed, separately or in combination, to combat counterfeits, 3 ACS Paragon Plus Environment

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including radio-frequency identification (RFID),5 nuclear track technology,6 laser holograms,7 and luminescent printings.8-9 Among them, luminescent printing has been not only widely used due to its simple operation, high-throughput production, and facile design, but also demonstrated its high security potentials for many different applications.10 However, most of luminescent-printed tags and patterns are still cloneable, largely because they are produced via a deterministic process so that the encrypted information stored in the luminescent tags/patterns are somehow predictable, which greatly limits their applications for high-level anti-counterfeiting.11-13

It is essential for the development of unclonable or difficult to cloneable luminescent printing tags/patterns for many anti-forgery applications. As compared to simple tags or patterns, barcodes as produced by the stochastic manufacturing processes usually possess several inherent advantages, including simple-to-fabricate, easy-to-track, large-data-storage, difficult-to-replicate, and industrial scale-to-produce at very low-cost.14 On the other hand, given that traditional anti-counterfeiting barcodes are

explicitly

visible

and

generally

produced

on

the

basis

of

the

pre-


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designed/determined coding rules, they are still crackable by well-skilled counterfeiters. So, it is still highly demanding to develop novel materials and fabrication processes for producing advanced barcodes against sophisticated counterfeiters. To address the abovementioned problem, invisible luminescent anti-counterfeiting barcodes, made of organic luminescent dyes,15-16 semiconductor quantum dots (QDs),17-18 metal-organic frameworks (MOFs),19-21 are considered as promising strategy for anti-counterfeiting applications. But, the challenges still remain. For instance, organic fluorescent materials generally have broad emission bands and often cause some overlaps between spectroscopic bands, thus reducing a possibility for certain securable bands for barcoded materials.22 Semiconductor quantum dot materials emit a relatively narrow spectroscopic band, but they are often fabricated by toxic substances (e.g., CdSe, CdS, and CdTe).23,24 MOFs could be the better anti-counterfeiting materials because of their tunable luminescence properties and high ink compatibility, but the low yielding from MOFs synthesis still possesses a great challenge for scaling-up their potential applications.25-27 Differently, carbon dots (CDs) as novel luminescent materials possess versatile advantages (e.g. high solution dispersion, unique optoelectronic 5 ACS Paragon Plus Environment

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properties, different coordination geometries, benign biocompatibility, and low-cost) for anti-counterfeiting applications.28-30 For instance, Zhu et al.31 prepared bright blueemitting CDs as fluorescent inks to print different invisible luminescent patterns for anticounterfeiting barcodes and QR codes. Zbořil et al.32 fabricated fluorescence-lifetimeencoded CD fluorescent inks compatible with different printing techniques (e.g. handwriting, inkjet printing, and transfer printing) for creating high-level security images. All of the abovementioned works have used downconversion (DC) luminescent materials (e.g. organic fluorescein, QDs, MOFs, and CDs) for anti-counterfeiting barcodes. Different from DC materials, the lanthanide ion-based (Ln3+)-doped NaYF4 (NaYF4: Ln3+) upconversion (UC) luminescent materials possess many advantages including sharp emission peaks, long fluorescence lifetime, low toxicity, and superior photostability, making them ideal candidates for different optical/imaging applications.3338

Lining with other works,39-41 we recently fabricated tunable, full-color, UC luminescent

anti-counterfeiting barcodes using transparent lanthanide-doped NaYF4/poly(vinyl alcohol) composites.42 In most cases, UC-based anti-counterfeiting materials still exhibit single-mode emission and are susceptible for cracking by counterfeiters. To increase 6 ACS Paragon Plus Environment

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information security and to better prevent counterfeiting, new luminescence encoding technologies strive to combine fluorescence reporters (e.g. ﬂuorescence molecules and QDs) with detectable probes (e.g. surface enhanced Raman scattering probes,43 structural colors,44 and magnetic signals45). However, these security probes can only be detected and decoded by specific analytical instruments and procedures. Alternatively, the combination of DC and UC luminescent materials to create dual-mode composite luminescent materials offers alternative low-cost strategy for the next-generation anticounterfeiting barcodes.46 Several DC and UC dual-mode composite luminescent materials including Gd2O3:Yb3+/Er3+/Eu(DBM)3Phen,47 Gd1.7Yb0.2Er0.3O3/Zn0.98Mn0.02S,48 NaYF4:Yb,Er@NaYF4@mSiO2-[Ru(dpp)3]2+Cl2 complex,49 and oleic acid-stabilized lanthanide-doped NaYF4 nanocrystals50 have been developed for improving anticounterfeiting barcodes. Recently, NaYF4: Ln3+/CDs dual-mode luminescent materials have attracted significant efforts in anti-counterfeiting technologies due to both UC luminescence of NaYF4: Ln3+ nanocrystals and DC luminescence of CDs. Wu et al.51 presented a straightforward solvothermal method to synthesize dual-mode luminescent


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NaYF4:Yb, Er(Tm)/CDs composites for anti-counterfeiting barcodes. However, CDs in this study exhibited relatively poor adsorption on the surface of UC materials. In this work, we proposed a new core-shell structural design strategy to prepare the

sandwich-like

upconversion

nanoparticles@carbon

dots@meso-SiO2

(UCNPs@CDs@mSiO2) core-shell nanohybrids by the encapsulation of both fluorescent materials of lanthanide-doped NaYF4 upconversion nanoparticles (UCNPs) and carbon dots (CDs) into mesoporous silica (mSiO2). Since CDs were buried in between a mSiO2 shell and a UCNPs core, the resultant UCNPs@CDs@mSiO2 nanohybrids formed a stable sandwich-like structure, which helps to improve photobleaching resistance and luminescence properties under acidic conditions. By tuning the core UCNPs of different UC luminescence (R-UCNPs, G-UCNPs and BUCNPs), three kinds of dual-mode luminescent UCNPs@CDs@mSiO2 nanohybrids were successfully prepared to produce RGB UC luminescence and blue DC luminescence.

The

resultant

UCNPs@CDs@mSiO2

nanohybrids

with

tunable

luminescence were further fabricated into different luminescent inks for producing threedimension anti-counterfeiting barcodes via inkjet printing. The barcodes were highly 8 ACS Paragon Plus Environment

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sensitive to exhibit dual-mode multicolor changes in response to the irradiation of a 980 nm laser or a 365 nm UV light. This work presents a new structural-based design and a simple fabrication strategy to prepare highly sensitive, dual-mode, light/color-responsive luminescent inks of UCNPs@CDs@mSiO2 for creating highly security and reliable anticounterfeiting barcodes, which are promising for multimodal optical anti-counterfeiting applications. 2. Materials and Methods Due to page limitation, all experimental details were presented in Supporting Information. 3. Results and Discussion Scheme 1 presents both synthesis details and dual-mode fluorescence properties of the sandwiched UCNPs@CDs@mSiO2 core-shell nanohybrids. Briefly, UCNPs and CDs were first synthesized separately using the thermal decomposition method and the hydrothermal method, respectively. Then, the as-prepared hydrophobic UCNPs were modified into hydrophilic ones by replacing hydrophobic OA molecules with hydrophilic CTAB ligands to produce CTAB-captured UCNPs. Upon mixing CTAB-captured UCNPs 9 ACS Paragon Plus Environment

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with CDs solution, the electrostatic interactions between the two species would drive carboxylic groups functionalized CDs (negatively charged) to be absorbed onto the surface of CTAB-captured UCNPs (positively charged). Furthermore, both UCNPs and CDs were simultaneously encapsulated into mSiO2 gels to form sandwich-like UCNPs@CDs@mSiO2 core-shell nanohybrids via a sol-gel process of TEOS. The resultant nanohybrids possessed a dual-mode luminescence property from both CDs and UCNPs fluorescent materials. Next, the as-obtained UCNPs@CDs@mSiO2 nanohybrids were dispersed into a mixture solvent of ethanol, deionized water, and glycerol to form environmental-benign dual-mode UCNPs@CDs@mSiO2 luminescent inks. By tailoring the UC luminescence of different core UCNPs (R-UCNPs, G-UCNPs and B-UCNPs), three types of dual-mode luminescent UCNPs@CDs@mSiO2 inks were generated to exhibit both RGB UC luminescence and blue DC luminescence. Finally, the UCNPs@CDs@mSiO2 inks were used to create dual-mode fluorescent barcodes by inkjet printing for anti-counterfeiting applications.


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Scheme 1. Schematic of both synthesis details and dual-mode fluorescence/color properties of sandwiched UCNPs@CDs@mSiO2 core-shell nanohybrids for anticounterfeiting barcodes.

To confirm the successful preparation of UCNPs@CDs@mSiO2 nanohybrids, we performed the side-by-side comparison for their composition, morphology, structure, and optical properties of G-UCNPs, CDs, and G-UCNPs@CDs@mSiO2 nanoparticles. Firstly, Fig. 1 shows the FTIR spectra of (a) OA captured G-UCNPs, (b) CTAB captured G-UCNPs, (c) CDs, and (d) G-UCNPs@CDs@mSiO2. OA captured G-UCNPs (curve a) exhibited the two peaks at 2923 and 2850 cm-1 corresponding to the characteristic 11 ACS Paragon Plus Environment

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asymmetric and symmetric stretching vibrations of methylene (CH2) in the long alkyl chains from OA ligands, as well as additional two peaks at 1628 and 1573 cm-1 corresponding to asymmetric and symmetric stretching vibrations of carboxylic group (COO-). After ligand exchange, the peaks of the methylene (CH2) become more intense and three new peaks at 965 and 912 cm-1 corresponding to asymmetric and symmetric stretching vibrations of C-N+, and 3017 cm-1 belonging the bending vibration of C-N+ were observed (curve b). This indicates the successful replacement of OA with CTAB on UCNPs and formation of CTAB captured G-UCNPs. In the FTIR spectrum of CDs (curve b), several typical bands, including the stretching vibrations of C-H at 2923 cm-1 and 2850 cm-1, vibrational absorption band of C=O at 1635 cm-1 and bending vibrations of N-H at 1570 cm-1, were found to be ascribed to carboxylic and amino groups on the surface of CDs.51,54 Furthermore, we prepared two samples of G-UCNPs@CDs@mSiO2 and G-UCNPs@mSiO2 in the presence and absence of CDs for comparison. It can be seen

that

upon

encapsulation

of

both

G-UCNPs

and

CDs

into

G-

UCNPs@CDs@mSiO2, all characteristic bands from G-UCNPs and CDs (2923 cm-1, 2850 cm-1, 1635 cm-1, and 1570 cm-1) still existed, but a new symmetrical stretching 12 ACS Paragon Plus Environment

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vibration of Si-O-Si at ~1080 cm-1 was found to confirm the formation of a silica layer.55 However, G-UCNPs@mSiO2 was lack of a characteristic peak of 1570 cm-1 corresponding to CDs components (curve d). The FTIR results confirmed that CDs were successfully incorporated into the nanohybrids of G-UCNPs@CDs@mSiO2.

Figure 1. FTIR spectra of (a) OA-captured G-UCNPs, (b) CTAB-captured G-UCNPs, (c) CDs, (d) G-UCNPs@CDs@mSiO2 and (e) G-UCNPs@mSiO2. To further validate the chemical identity of each hybrid systems, Fig. 2 shows a comparative elemental analysis of G-UCNPs@CDs@mSiO2 and G-UCNPs@mSiO2 using XPS spectrum. Both G-UCNPs@CDs@mSiO2 and G-UCNPs@mSiO2 showed similar XPS peaks, including four strong peaks at 160.0 eV (Y3d), 302.0 eV (Y3p),


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685.0 eV (F1s), 1072.0 eV (Na1s), corresponding to NaYF4 host matrix in G-UCNPs56, two weak peaks at 285.0 and 532.0 eV corresponding to functional organic groups on the surface of G-UCNPs, and a peak at 103.2 eV corresponding to Si2p of SiO2. On the other hand, the inset of Fig. 2A (the magnified XPS spectra in 430~370 eV) showed that G-UCNPs@CDs@mSiO2 presented a distinct peak at 397.0 eV assigning to N1s from the CDs,57 which were absent from G-UCNPs@mSiO2. In addition, the C1s spectra of the two samples (Fig. 2B) gave further demonstration. As shown, the C1s spectrum of GUCNPs@CDs@SiO2 appeared two different peaks at 286.6 and 288.9 eV, which are associated with C-N and C=N/C=O, while only one peak corresponding to the C-C bond was observed in the C1s spectrum of G-UCNPs@SiO2, further confirming the presence of CDs on the shell of the G-UCNPs@CDs@SiO2 nanohybrids. Both FTIR and XPS results consistently confirm that the CDs are successfully incorporated into the mSiO2 shell to form the nanohybrids of G-UCNPs@CDs@mSiO2.


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Figure 2. XPS (A) survey and (B) C1s spectra of G-UCNPs@CDs@mSiO2 and GUCNPs@mSiO2. The inset (A) shows the magnified XPS spectra in 430~370 eV. Then, TEM was utilized to characterize the size and morphology of G-UCNPs, CDs, and G-UCNPs@CDs@mSiO2. As controls, G-UCNPs presented a uniform spherical structure with an average diameter of ~24 nm (Fig. 3A), while CDs presented as ultra-small nanoparticles with average size of 1~2 nm (small dark dots, Fig. 3B). Both G-UCNPs and CDs nanoparticles showed uniform size distributions without apparent aggregation and core-shell structures. Differently, while G-UCNPs@CDs@mSiO2 also exhibited highly monodispersed and uniform spherical shapes with a similar average diameter of ~38 nm (Fig. 3C), they clearly possessed an visible core-shell structure with


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mesoporous silica deposited on the surface of G-UCNPs (Fig. 3D). At the higher magnification, the average thickness of the mSiO2 shell was measured to be ~7 nm. In addition, G-UCNPs@mSiO2 exhibited similar size and morphology to the GUCNPs@CDs@mSiO2 (Fig. S1), indicating that the incorporation of CDs has no or little effect on the mSiO2 shell coating. Different from white G-UCNPs@mSiO2 powders without incorporation of CDs (inset in Fig. S1), G-UCNPs@CDs@mSiO2 powders showed an apparent pale yellow (inset in Fig. 3C) due to the incorporation of white GUCNPs (inset in Fig. 3A) into yellow CDs (inset in Fig. 3B), again demonstrating the successful incorporation of CDs into the G-UCNPs@CDs@mSiO2 nanohybrids, consistent with the aforementioned FTIR and XPS results.


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Figure 3. Representative TEM images of (A) G-UCNPs, (B) CDs, and (C-D) GUCNPs@CDs@mSiO2 at different resolutions. Inset optical images represent the solid powder of G-UCNPs, the aqueous dispersion of CDs, and solid powder of GUCNPs@CDs@mSiO2, respectively. Further, STEM was used to characterize the distribution of CDs in GUCNPs@CDs@mSiO2 and G-UCNPs@mSiO2 sample. In Fig. 4, a series of STEM images of the G-UCNPs@CDs@mSiO2 showed the elemental mapping for Y (blue), Yb (purple), C (red), N (green), and Si (pink), demonstrating the coexistence of these elements in the G-UCNPs@CDs@mSiO2. Si from mSiO2 was distributed at the outer shell, both Y and Yb elements from G-UCNPs were distributed at the inner core, and C and N elements from CDs were sandwiched between G-UCNPs core and mSiO2 shell, indicating the sandwiched core-shell structure of G-UCNPs@CDs@mSiO2 nanohybrids (the inset of Fig. 4).


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Figure 4. STEM images of G-UCNPs@CDs@mSiO2 to show different distribution maps of C, N, Si, Y, and Yb elements. An inset shows a representative 3D image of GUCNPs@CDs@mSiO2. To further determine whether CDs were buried in the mesopores of mSiO2 shells, nitrogen adsorption-desorption isotherms were used to analyze the mesostructured of G-UCNPs@CDs@mSiO2 and G-UCNPs@mSiO2. As shown in Fig. 5, both GUCNPs@CDs@mSiO2 and G-UCNPs@mSiO2 exhibited the type IV isotherms with a distinct adsorption step at relative pressure (p/po) of 0.40-0.80, indicating the


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mesoporous

structure

of

G-UCNPs@CDs@mSiO2

and

G-UCNPs@mSiO2.

G-

UCNPs@CDs@mSiO2 displayed the much smaller specific surface area (66.87 m2/g vs 148.75 m2/g) and total pore volume (0.194 cm3/g vs 0.259 cm3/g) than GUCNPs@mSiO2, probably because the CDs were incorporated into the mesopores of G-UCNPs@CDs@mSiO2 led to a more compact porous structure.

Figure 5. N2 adsorption-desorption isotherms of G-UCNPs@CDs@mSiO2 and GUCNPs@mSiO2. XRD data demonstrated a crystal phase of the synthesized G-UCNPs and a pure hexagonal phase NaYF4 of G-UCNPs (Fig. S2a). Besides, the incorporation of CDs and the coating of mSiO2 shell did not largely affect the crystal phase of G-UCNPs (Fig.


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S2c). Due to the presence of hexagonal NaYF4 phase, G-UCNPs@CDs@mSiO2 displayed a relatively high upconversion luminescent intensity. The UV-vis absorption spectrum of CDs solution (Fig. S3) showed two absorbance peaks: one peak at ~238 nm was ascribed to the blue-shifted π−π* transition of aromatic sp2 domains, while another peak at ~340 nm was ascribed to the two function groups of C=O (4.1 eV, 300 nm, n-p*) and C=N (2.9 eV, 421 nm, n-p*).58 Furthermore, at the maximum excitation of 350 nm, CDs solution exhibited a strong emission peak at 443 nm with a Stokes shift of 93 nm (Fig. S3), leading to 56.6% of QY (Quantum yield, Φ) (Fig. S4), consistent with the

values

reported

in

literature.54

Such

optical

properties

make

G-

UCNPs@CDs@mSiO2 good candidate for anti-counterfeiting luminescent inks. Subsequently, both DC and UC luminescent properties of CDs, G-UCNPs and GUCNPs@CDs@mSiO2 were tested. In the case of DC fluorescence tests, Fig. 6A showed that both CDs and G-UCNPs@CDs@mSiO2 exhibited an emission peak at 443 nm (blue light) under 350 nm excitation, while G-UCNPs did not present any peak, instead of a straight line. Such difference was also confirmed by the direct visual inspection of the three samples, among which CDs and G-UCNPs@CDs@mSiO2 20 ACS Paragon Plus Environment

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solutions showed bright blue luminescence under a 365 nm lamp, while G-UCNPs cyclohexane solution presented no DC luminescence. So, the presence of CDs gave rise

of

blue

downconversion

luminescence

in

the

G-UCNPs@CDs@mSiO2

nanohybrids. In parallel, UC luminescence tests in Fig. 6B showed that G-UCNPs and G-UCNPs@CDs@mSiO2 presented four common emission peaks at 408 nm, 521 nm, 544 nm and 654 nm with different intensities, and these peaks were attributed to the transitions of 2H9/2-4I15/2, 2H11/2-4I15/2, 4S3/2-4I15/2, and 4F9/2-4I15/2 of Er3+, respectively. While G-UCNPs and G-UCNPs@CDs@mSiO2 displayed bright green fluorescence under a 980 nm laser, G-UCNPs@CDs@mSiO2 decreased its luminescent intensity by 30% as compared to pure G-UCNPs. Besides, G-UCNPs@CDs@mSiO2 exhibits good photobleaching resistance property and luminescent stability by protecting CDs from destroying or quenching under acidic conditions (Fig. S5). Therefore, slight reduction of UC luminescence allows G-UCNPs@CDs@mSiO2 to possess stable dual-mode fluorescence from CDs and G-UCNPs.


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Figure 6. (A) Downconversion and (B) upconversion luminescent spectra of G-UCNPs, CDs and G-UCNPs@CDs@mSiO2. The upconversion luminescent spectra are normalized to the maximum intensity of 4S3/2-4I15/2 transition. The insets show the optical images of G-UCNPs cyclohexane dispersion (1.0 mg/mL), CDs (2.010-3 mg/mL), and G-UCNPs@CDs@mSiO2 aqueous (1.0 mg/mL) dispersions under (A) a 365 nm light and (B) a 980 nm laser, respectively. Generally speaking, highly secured barcodes should be able to generate plentiful coding combinations by realizing the multiple emission colors in a controllable way. Herein, by tailoring the type and concentration of lanthanide dopants in the NaYF4 core, two types of nanoparticles made of NaYF4: 10% Er3+, 2% Tm3+ and NaYF4: 25% Yb3+, 0.3% Tm3+ were prepared with respective red and blue UC luminescence. TEM images showed that the as-prepared NaYF4:10% Er3+, 2% Tm3+ (inset of Fig. 7A) and NaYF4:


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25% Yb3+, 0.3% Tm3+ nanoparticles (inset of Fig. 7C) had elliptic shapes with uniform size of 19 nm and 21 nm, respectively. Due to the low luminescent intensity, an inert NaYF4 layer was epitaxial grown onto the surface of the two UCNPs, respectively, which suppressed the surface defect-induced quenching effect and formed NaYF4: 10% Er3+, 2% Tm3+@NaYF4 and NaYF4: 25% Yb3+, 0.3%Tm3+@NaYF4 with enhanced luminescent intensity. The samples of NaYF4: 10% Er3+, 2% Tm3+@NaYF4 and NaYF4: 25% Yb3+, 0.3%Tm3+@NaYF4 were denoted as R-UCNPs and B-UCNPs, respectively. XRD patterns (Fig. S6) results showed that R-UCNPs and B-UCNPs contained pure hexagonal phase NaYF4 nanocrystals. R-UCNPs (Fig. 7A) and B-UCNPs (Fig. 7C) presented similar and uniform nanorod morphologies with average length/diameter of 36 nm/21 nm and 34 nm/23 nm, respectively. Different size and morphology of RUCNPs and B-UCNPs in comparison with the original core nanoparticles demonstrate the successful epitaxial growth of NaYF4 shell on the surface of R-UCNPs and BUCNPs. Upon incorporating both CDs and mSiO2 shell into R-UCNPs and B-UCNPs, both resultant R-UCNPs@CDs@mSiO2 (Fig. 7B) and B-UCNPs@CDs@mSiO2 (Fig. 7D) nanohybrids exhibited the sandwich-like core-shell architecture, where the average 23 ACS Paragon Plus Environment

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thickness of the mSiO2 shell was about 7 nm similar to G-UCNPs@CDs@mSiO2 (Fig. 3C).

More

importantly,

R-UCNPs@CDs@mSiO2

and

B-UCNPs@CDs@mSiO2

displayed dual-mode luminescent properties, as shown in the luminescent spectra (Fig. S7 A-C) and the optical images in aqueous dispersion (Fig. S7D), i.e. RUCNPs@CDs@mSiO2 displayed red upconversion emission under a 980 nm laser and blue DC emission under a 365 nm lamp (Fig. S7D), while B-UCNPs@CDs@mSiO2 exhibited blue upconversion emission under a 980 nm laser and blue DC emission under a 365 nm UV lamp (Fig. S7D).

Figure 7. TEM images of (A) R-UCNPs, (B) R-UCNPs@CDs@mSiO2, (C) B-UCNPs and (D) B-UCNPs@CDs@mSiO2. The insets in (A) and (B) showed the TEM images of


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the synthesized NaYF4: 10% Er3+, 2% Tm3+ and NaYF4: 25% Yb3+, 0.3% Tm3+ nanoparticles, respectively. The insets in (C) and (D) represented the schematic 3D images of R-UCNPs@CDs@mSiO2 and B-UCNPs@CDs@mSiO2, respectively. For anti-counterfeiting applications, we prepared different dual-mode luminescent inks by separately dispersing R-UCNPs@CDs@mSiO2, G-UCNPs@CDs@mSiO2, and B-UCNPs@CDs@mSiO2 into a mixture solvent of ethanol, water, and glycerol at 2:2:1 weight ratio. The experimental formulas to prepare the three inks were summarized in Table S1. Three inks contained different content of R-UCNPs@CDs@mSiO2, GUCNPs@CDs@mSiO2, and B-UCNPs@CDs@mSiO2 (0.80 wt% in Ink 1, 0.08 wt% in Ink 2, and 0.10 wt% in Ink 3) in order to achieve similar perceived UC fluorescence brightness, but different DC fluorescence brightness. The resultant inks are stable for several weeks with proper dynamic viscosity and surface tension for inkjet printing (measured by the method as discussed elsewhere,59 and the data were shown in Table S1). Fig. 8 showed that the CIE color coordinates of the UC fluorescence of Ink 1 (marked as R), Ink 2 (marked as G), and Ink 3 (marked as B) were (0.62, 0.32), (0.27, 0.69) and (0.13, 0.08), respectively, which appear as distinguishable green, red, and 25 ACS Paragon Plus Environment

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blue colors to naked eyes under 980 nm laser (as shown in inset of Fig. 8). The three coordinates were closely to the edge of the chroma regions and the triangle composed by the three coordinates can cover most of the chromaticity diagram, indicating the good turnability of the UC fluorescence. The DC fluorescence of Ink 1 (marked as r), Ink 2 (marked as g), and Ink 3 (marked as b) were (0.15, 0.08), (0.16, 0.14) and (0.16, 0.12), respectively. They all present blue DC fluorescence, but the brightness of the blue emission colors was different.

Figure 8. CIE color coordinates of UC luminescent (R, G, B, black point) and DC luminescent (r, g, b, white asterisk) of the three R-UCNPs@CDs@mSiO2, G-


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UCNPs@CDs@mSiO2, and B-UCNPs@CDs@mSiO2 inks. The insets show typical dual-mode optical images of three inks under 365 nm lamp and 980 nm laser. Different from stamp or screen printing, inkjet printing enables to produce more complex and high-resolution luminescent patterns. As a proof of concept, we used the three

dual-mode

luminescent

inks

made

of

R-UCNPs@CDs@mSiO2,

G-

UCNPs@CDs@mSiO2, and B-UCNPs@CDs@mSiO2 to create different complex, dualmode, fluorescent patterns on paper by inkjet printing. In Fig. S8, using Ink 1 (group a), the encrypted red and blue patterns of a rose flower can be clearly observed under the irradiation of 980 nm laser and 365 nm UV lamp, respectively, but this flower was invisible under daylight. Similarly, inkjet printing of Ink 3 (group b) enabled to produce an invisible pattern under daylight, but the encrypted dual-mode blue luminescent pattern of a logo of “Hunan University of Technology” under both 980 nm and 365 nm. To further challenge our technique, we constructed a QR code by inkjet printing of the three dual-mode luminescent inks into three different regions on a regular paper. It can be seen in group c that under 980 nm light excitation, a colorful QR code emitted distinct high-resolution red, green, and blue UC luminescence. Under a 365 nm UV 27 ACS Paragon Plus Environment

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light, while this QR code only presented blue DC luminescence, the careful visual inspection showed that the brightness of the blue DC luminescence in the area printed by Ink 1 was greater than the areas printed by Ink 2 and Ink 3. This could be attributed to the much higher concentration of R-UCNPs@CDs@mSiO2 in luminescent ink than G-UCNPs@CDs@mSiO2 and B-UCNPs@CDs@mSiO2 (Table 1).

Considering the color tunability of UC fluorescence (RGB) and different DC fluorescence brightness of Ink 1 with Ink 2 and Ink 3, we created three-dimension (3D) luminescent barcodes by separately printing of these three dual-mode luminescent inks. Compared with the traditional 2D barcodes which were usually encrypted information by using the space distribution of the ordinary black inks or single-mode fluorescence inks,43-45 the proposed dual-mode 3D barcodes provided huge information storage capacity and high level of anti-counterfeiting property. Similarly, the standard Code-93 rule was employed to build the barcodes, where each character was represented by 3 “bars” and 3 “spaces”, 1 to 4 modules wide. Fig. 9a defines the encoding terminology of the 3D luminescent barcodes. Briefly, the first dimensional code (1stD code) consists of


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the widths of the bars and spaces of the original barcode system, labeled “1”, “2”, “3” and “4”. Meanwhile, the UC emission color (2ndD code) and DC brightness (3rdD code) created another two dimension verified codes. The red, green and blue UC emission color were labeled as the numbers “1”, “2” and “3”, respectively. The DC fluorescence brightness can be divided into two levels as dim and bright, which were marked as “1” and “2”. The number “0” represents the case where no fluorescent ink was deposited. As compared to a very limited number of 55 possible combinations of bars and spaces for the conventional Code-93 system, our strategy is able to produce a much larger coding combinations for dual-mode luminescence barcodes, i.e. a total of 1485 possible combinations (N=33×55) can be used to generate 3D fluorescent barcodes of various widths and interspaces, different UC emission color and DC brightness. We construct a 3D encrypted system containing 34 characters (26 letters and 8 numbers) (Table S2) based on the defined encoding terminology of the 3D luminescent barcodes. As a conceptual example, three codes for letters “H”, “U” and “T” were designed by printing barcodes of various widths and interspaces with different dual-mode luminescent inks, as shown in Fig. 9b. In a decrypted step, firstly, three luminescent barcodes can be 29 ACS Paragon Plus Environment

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observed under the irradiation of a 980 nm laser. Based on the luminescent barcodes, the 1stD code was read out by the arrangement of the fluorescent “bars” and nonfluorescent “space”, and the 2ndD code judged by UC emission color. The information

112211   221120   211220  can be collected as two-dimensional matrixes of  ,  , and    , 302010   203010  302010  respectively. Then, another three barcodes can be obtained under a 365 nm lamp, which contains information of the same 1stD code and additional 3rdD code (DC brightness),

112211   221120   211220  and read out as two-dimensional matrixes of  ,  , and    , 101020  101020  101020  respectively. Combine the two results, the luminescent barcodes can be decrypted into

112211  three-dimensional (3D) matrixes of 302010  , 101020 

 221120   203010  , and   101020 

 211220  302010  (Fig. 9b).   101020 

For practical uses, we finally printed a standard Code-93 barcode containing the “Start”, “Data”, “Check” and “Stop” parts on a medicine packaging box (no background fluorescent) using the three dual-mode luminescent inks. The resultant barcodes can be read out by the corresponding luminescent images under a 980 nm laser and a 365 nm light (Fig. 9c). According to the width of fluorescent bars and spaces in the “Data”


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region, we can decrypt the first-dimension information of “HUT” from the fluorescent barcode image under a 980 nm laser. Then, considering the UC emission color arrangement, the second-dimension information of “UHV” was decrypted based on the predefined “2ndD Code”. Furthermore, the 3rdD code of “141” can be obtained by inspecting the blue brightness difference of the “bars” in the luminescent barcode images under a 365 nm lamp. This kind of 3D luminescent barcodes is believed to have wide applications in anti-counterfeiting package, which can be acted as an “authentication code” to track or certify the quality of products.


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Figure 9. (a) The encoding terminology of 3D luminescent barcodes, (b) a conceptual example to describe the design and the decryption of typical 3D luminescent barcodes, (c) inkjet printing a standard Code-93 barcode on a medicine packaging box for practical uses. 4. Conclusions


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In this work, we have successfully developed a new dual-mode fluorescent system made of UCNPs@CDs@mSiO2 nanohybrids with a sandwich-like core-shell structure. From structural design of viewpoint, by depositing mSiO2 shell onto UCNPs and CDs, the resultant UCNPs@CDs@mSiO2 nanohybrids achieved a well-defined sandwich-like core-shell structure, and the enclosing of mSiO2 shell enhanced photo-bleaching resistance property upon exposed to UV light and luminescent stability under acidic conditions, both contributing to highly sensitive luminescent emission. Secondly, by introducing both fluorescent UCNPs and CDs into the sandwich core-shell structure via non-covalent interactions, UCNPs@CDs@mSiO2 nanohybrids realized dual-mode photo-responsive fluorescence. Next, by tuning the core UCNPs of different UC luminescence, three different types of dual-mode luminescent UCNPs@CDs@mSiO2 nanohybrids were prepared to achieve RGB UC luminescence under the irradiation a 980 nm laser and blue DC luminescence under a 365 nm UV lamp. More importantly, the three UCNPs@CDs@mSiO2 nanohybrids were fabricated into water-based, environmental benign luminescent security inks, which were used for inkjet printing different, dual-mode, high-resolution, luminescent patterns (rose flower, a logo of 33 ACS Paragon Plus Environment

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“Hunan University of Technology” and a QR code) on a paper. All of these patterns were invisible in daylight, but display different UC/DC colors under a 980 nm laser and a 365 nm UV lamp, demonstrating high-security and information-hidden nature. Furthermore, by taking advantages of the color tunability of UC fluorescence (RGB) and the different DC fluorescence brightness of three inks, three-dimensional luminescent barcodes with high coding capacity can be readily realized by inkjet printing. The anticounterfeiting barcodes are highly secure and easy to authenticate using a portable device. Therefore, this dual-mode nanohybrid fluorescent system, combined with its facile preparation, is highly promising for developing next-generation anti-counterfeiting technology and products. Conflicts of interest: The authors declared no competing financial interest. Supporting Information: Electronic supplementary information (ESI) available, including all experimental details and characterizations by eight Figures and two tables. TEM, XRD, UV/vis, optical images were used to characterize and confirm the synthesis, chemical identities, structural morphologies, and luminescence of different UCNPs@CDs@mSiO2 and the control samples, as well as the construction of anti-counterfeiting fluorescent patterns on paper by inkjet printing. 34 ACS Paragon Plus Environment

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Acknowledgements: The financial support by the National Science Foundation of China (51874129 and 51874128), National Key Research and Development Program of China (No. 2018YFD0400705), the Science Foundation of Hunan Province (2018JJ3115 and 2019JJ60049) and Graduate Innovation Research Foundation of Hunan Province (CX2018B730) is gratefully acknowledged. References 1.

Smith, A. F.; Skrabalak, S. E. Metal Nanomaterials for Optical Anti-counterfeit Labels. J. Mater. Chem. C 2017, 5, 3207-3215.

2.

Fei, J.; Liu, R. Drug-laden 3D Biodegradable Label Using QR Code for Anti-counterfeiting of Drugs. Mater. Sci. Eng. C 2016, 63, 657-62.

3.

Kim, J.; Yun, J. M.; Jung, J.; Song, H.; Kim, J. B.; Ihee, H. Anti-counterfeit Nanoscale Fingerprints Based on Randomly Distributed Nanowires. Nanotechnology 2014, 25, 155303.

4.

Yoon, B.; Lee, J.; Park, I. S.; Jeon, S.; Lee, J.; Kim, J. -M. Recent Functional Material Based Approaches to Prevent and Detect Counterfeiting. J. Mater. Chem. C 2013, 1, 2388-2403.

5.

Singh, R.; Singh, E.; Nalwa, H. S. Inkjet Printed Nanomaterial Based Flexible Radio Frequency Identification (RFID) Tag Sensors for The Internet of Nano Things. RSC Adv. 2017, 7, 48597-48630.

6.

Cadarso, V. J.; Chosson, S.; Sidler, K.; Hersch, R. D.; Brugger, J. High-resolution 1D Moirés As Counterfeit Security Features. Light-Sci. Appl. 2013, 2, e86-e86.

7.

Park, I. Y.; Ahn, S.; Kim, Y.; Bae, H. S.; Kang, H. S.; Yoo, J.; Noh, J. Serial Number Coding and Decoding by Laser Interference Direct Patterning on the Original Product Surface for Anti-counterfeiting. Opt. Express 2017, 25, 14644-14653. 35 ACS Paragon Plus Environment

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8.

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Andres, J.; Hersch, R. D.; Moser, J. -E.; Chauvin, A. -S. A New Anti-counterfeiting Feature Relying on Invisible Luminescent Full Color Images Printed with Lanthanide-based Inks. Adv. Funct. Mater. 2014, 24, 5029-5036.

9.

Kumar, P.; Singh, S.; Gupta, B. K. Future Prospects of Luminescent Nanomaterial Based Security Inks: From Synthesis to Anti-counterfeiting Applications. Nanoscale 2016, 8, 14297-14340.

10. Meruga, J. M.; Cross, W. M.; Stanley May, P.; Luu, Q.; Crawford, G. A.; Kellar, J. J. Security Printing of Covert Quick Response Codes Using Upconverting Nanoparticle Inks. Nanotechnology 2012, 23, 395201. 11. Hu, L.; Fan, Y.; Liu, L.; Li, X.; Zhao, B.; Wang, R.; Wang, P.; El-Toni, A. M.; Zhang, F. Orthogonal Multiplexed Luminescence Encoding with Near-infrared Rechargeable Upconverting Persistent Luminescence Composites. Adv. Opt. Mater. 2017, 5, 1700680. 12. Liu, X.; Wang, Y.; Li, X.; Yi, Z.; Deng, R.; Liang, L.; Xie, X.; Loong, D. T. B.; Song, S.; Fan, D.; All, A. H.; Zhang, H.; Huang, L.; Liu, X. Binary Temporal Upconversion Codes of Mn2+-activated Nanoparticles for Multilevel Anti-counterfeiting. Nat. Commun. 2017, 8, 899. 13. Ramalho, J. F. C. B.; António, L. C. F.; Correia, S. F. H.; Fu, L. S.; Pinho, A. S.; Brites, C. D. S.; Carlos, L. D.; André, P. S.; Ferreira, R. A. S. Luminescent QR Codes for Smart Labelling and Sensing. Opt. Laser Technol. 2018, 101, 304-311. 14. Shikha, S.; Salafi, T.; Cheng, J.; Zhang, Y. Versatile Design and Synthesis of Nanobarcodes. Chem. Soc. Rev. 2017, 46, 7054-7093. 15. Tan, W.; Li, X.; Zhang, J.; Tian, H. A Photochromic Diarylethene Dyad Based on Perylene Diimide. Dyes Pigm. 2011, 89, 260-265. 16. Kobatake, S.; Imagawa, H.; Nakatani, H.; Nakashima, S. The Irreversible Thermo-bleaching Function of A Photochromic Diarylethene Having Trimethylsilyl Groups. New J. Chem. 2009, 33, 1362-1367. 36 ACS Paragon Plus Environment

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17. Sun, L. -W.; Shi, H. -Q.; Li, W. -N.; Xiao, H. -M.; Fu, S. -Y.; Cao, X.-Z.; Li, Z. -X. Lanthanum-doped ZnO Quantum Dots with Greatly Enhanced Fluorescent Quantum Yield. J. Mater. Chem. 2012, 22, 8221-8227. 18. Kshirsagar, A.; Jiang, Z.; Pickering, S.; Xu, J.; Ruzyllo, J. Formation of Photo-Luminescent Patterns on Paper Using Nanocrystalline Quantum Dot Ink and Mist Deposition. ECS J. Solid State Sc. 2013, 2, R87-R90. 19. Gao, M. L.; Wang, W. J.; Liu, L.; Han, Z. B.; Wei, N.; Cao, X. M.; Yuan, D. Q. Microporous Hexanuclear Ln(III) Cluster-Based Metal-Organic Frameworks: Color Tunability for Barcode Application and Selective Removal of Methylene Blue. Inorg. Chem. 2017, 56, 511-517. 20. Wang, Y. M.; Tian, X. T.; Zhang, H.; Yang, Z. R.; Yin, X. B. Anticounterfeiting Quick Response Code with Emission Color of Invisible Metal-Organic Frameworks as Encoding Information. ACS Appl. Mater. Inter. 2018, 10, 22445-22452. 21. Yang, Q. Y.; Pan, M. S.; Wei, C.; Li, K.; Du, B. B.; Su, C. Y. Linear Dependence of Photoluminescence in Mixed Ln-MOFs for Color Tunability and Barcode Application. Inorg. Chem. 2015, 54, 5707-5716. 22. Huo, J.; Hu, Z.; He, G.; Hong, X.; Yang, Z. High Temperature Thermochromic Polydiacetylenes: Design and Colorimetric Properties. Appl. Surf. Sci., 2017, 423, 951-956. 23. Ji, C. J.; Jiang, P. F.; Ye, X. F.; Chang, M. L.; Liu, F. H.; Shen, Y. Y.; Chen, D. C.; Nie, L. B. A Novel Suspension Detection of DNA Based on Quantum Dot Encoded Microbeads and Fluorescence Amplifying. Sci. Adv. Mater. 2019, 11, 680-684. 24. Fan, T.; Lv J.; Chen, Y.; Yuan, W.; Huang, Y. Random Lasing in Cesium Lead Bromine Perovskite Quantum Dots Film. J. Mater. Sci-Mater. El. 2019, 30, 1084-1088. 25. Ning, S.; Chen, H.; Zhang, S.; Cheng, P. A 2D Water-Stable Metal-Organic Framework for Fluorescent Detection of Nitroaromatics. Polyhedron 2018, 155, 457-463. 26. Zou, J. -Y.; Li, L.; You, S. Y.; Liu, Y. -W.; Cui, H. -M.; Cui, J. -Z.; Zhang, S. -W. Two 37 ACS Paragon Plus Environment

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Page 38 of 41

Luminescent Lanthanide(iii) Metal–Organic Frameworks as Chemosensors for HighEfficiency Recognition of Cr(vi) Anions in Aqueous Solution. Dalton Trans. 2018, 47, 15694-15702. 27. Zou, J. -Y.; Li, L.; You, S. -Y.; Cui, H. -M.; Liu, Y. -W.; Chen, K. -H.; Chen, Y. -H.; Cui, J. -Z.; Zhang, S. -W. Sensitive Luminescent Probes of Aniline, Benzaldehyde and Cr(VI) Based on A Zinc(II) Metal-Organic Framework and Its Lanthanide(III) PostFunctionalizations. Dyes Pigm. 2018, 159, 429-438. 28. Jiang, K.; Zhang, L.; Lu, J.; Xu, C.; Cai, C.; Lin, H. Triple-mode Emission of Carbon Dots: Applications for Advanced Anti-counterfeiting. Angew. Chem. Int. Ed. 2016, 55, 7231-7235. 29. Jiang, K.; Sun, S.; Zhang, L.; Lu, Y.; Wu, A.; Cai, C.; Lin, H. Red, Green, and Blue Luminescence by Carbon Dots: Full-color Emission Tuning and Multicolor Cellular Imaging. Angew. Chem. Int. Ed. 2015, 54, 5360-5363. 30. Liu, Y.; Zhou, L.; Li, Y.; Deng, R.; Zhang, H. Highly Fluorescent Nitrogen-doped Carbon Dots with Excellent Thermal and Photo Stability Applied as Invisible Ink for Loading Important Information and Anti-counterfeiting. Nanoscale 2017, 9, 491-496. 31. Zhu, L.; Yin, Y.; Wang, C. -F.; Chen, S. Plant Leaf-derived Fluorescent Carbon Dots for Sensing, Patterning and Coding. J. Mater. Chem. C 2013, 1, 4925-4932. 32. Kalytchuk, S.; Wang, Y.; Polakova, K.; Zboril, R. Carbon Dot Fluorescence-lifetimeencoded Anti-counterfeiting. ACS Appl. Mater. Inter. 2018, 10, 29902-29908. 33. Tan, H.; Xie, S.; Xu, J.; Feng, Y.; Zhang, C.; Zheng, J. Branched NaYF4:Yb, Er Upconversion Phosphors with Luminescent Properties for Anti-counterfeiting Application. Sci. Adv. Mater. 2017, 9, 2223-2233. 34. Tan, H.; Xie, S.; Li, N.; Tong, C.; Xu, L.; Xu, J.; Zhang, C. Synthesis and Characterization of NaYF4:Yb, Er Up-conversion Phosphors/poly(vinyl alcohol) Composite Fluorescent Films. Mater. Express 2018, 8, 141-148. 35. D. Gao, D.; Wang, D.; Zhang, X.; Feng, X.; Xin, H.; Yun, S.; Tian, D. Spatial Control of 38 ACS Paragon Plus Environment

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Upconversion Emission in A Single Fluoride Microcrystal via Excitation Mode and Native Interference Effect. J. Mater. Chem. C 2018, 6, 622-629. 36. Yao, W.; Tian, Q.; Wu, Wei. Tunable Emissions of Upconversion Fluorescence for Security Applications. Adv. Opt. Mater. 2019, 7, 1801171. 37. Fan, T.; Lu, J.; Lin, F.; Zhou, Z. Improved Luminescence in Water-Soluble Hollow LaF3: Eu3+ Nanoparticles by Introducing Li+ Ions. Mater. Res. Express 2016, 3, 045010. 38. Chang, M.; Hu, H.; Zhang, Y.; Chen, D.; Hu, H. Core-shell-core Heterostructural Engineering of Y2O3:Eu3+/MCM-41/YVO4:Eu3+ for Enhanced Red Emission and Tunable, Broadened-band Response to Excitation. J. Mater. Sci-Mater. El., 2017, 28, 16026-16035. 39. You, M.; Lin, M.; Wang, S.; Wang, X.; Zhang, G.; Hong, Y.; Dong, Y.; Jin, G.; Xu, F. Three-dimensional Quick Response Code Based on Inkjet Printing of Upconversion Fluorescent Nanoparticles for Drug Anti-counterfeiting. Nanoscale 2016, 8, 10096-10104. 40. Ma, Q.; Wang, J.; Li, Z.; Wang, D.; Hu, X.; Xu, Y.; Yuan, Q. Near-infrared-light-mediated High-throughput Information Encryption Based on the Inkjet Printing of Upconversion Nanoparticles. Inorg. Chem. Front. 2017, 4, 1166-1172. 41. Zhang, Y.; Zhang, L.; Deng, R.; Tian, J.; Zong, Y.; Jin, D.; Liu, X. Multicolor Barcoding in A Single Upconversion Crystal. J. Am. Chem. Soc. 2014, 136, 4893-4896. 42. Wang, M.; Xu, Y.; Tan, H.; Xu, L.; Zhang, C.; Xu, J. Multicolor Luminescent AntiCounterfeiting Barcode Based on Transparent Lanthanide-doped NaYF4/poly(vinyl alcohol) Nanocomposite with Tunable Full-color Upconversion Emission. Nanosci. Nanotechnol. Lett. 2018, 10, 365-372. 43. Li, D.; Tang, L.; Wang, J.; Liu, X.; Ying, Y. Multidimensional SERS Barcodes on Flexible Patterned Plasmonic Metafilm for Anticounterfeiting Applications. Adv. Opt. Mater. 2016, 4, 1475-1480. 44. Liu, K.; Tian, Y.; Li, Q.; Du, X.-Y.; Zhang, J.; Wang, C.-F.; Chen, S. Microfluidic Printing Directing Photonic Crystal Bead 2D Code Patterns. J. Mater. Chem. C 2018, 6, 2336-2341. 39 ACS Paragon Plus Environment

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Page 40 of 41

45. Li, R.; Zhang, Y.; Tan, J.; Wan, J.; Guo, J.; Wang, C. Dual-mode Encoded Magnetic Composite Microsphere Based on Fluorescence Reporters and Raman Probes as Covert Tag for Anticounterfeiting Applications. ACS Appl. Mater. Inter. 2016, 8, 9384-9394. 46. Xie, S.; Gong, G.; Song, Y.; Tan, H.; Zhang, C.; Li, N.; Zhang, Y.; Xu, L.; Xu, J.; Zheng, J. Design of Novel Lanthanide-doped Core-shell Nanocrystals with Dual Up-conversion and Down-conversion Luminescence for Anti-counterfeiting Printing. Dalton Trans. 2019, 48, 6971-6983. 47. Singh, S.K.; Singh, A.K.; Rai, S.B. Efficient Dual Mode Multicolor Luminescence in A Lanthanide Doped Hybrid Nanostructure: A Multifunctional Material. Nanotechnology 2011, 22, 275703. 48. Kumar, P.; Singh, S.; Gupta, B. K. A Novel Approach to Synthesise A Dual-mode Luminescent Composite Pigment for Uncloneable High-security Codes to Combat Counterfeiting. Chem-Eur. J. 2017, 23, 17144-17151. 49. Xu, S.; Yu, Y.; Gao, Y.; Zhang, Y.; Li, X.; Zhang, J.; Wang, Y.; Chen, B. Mesoporous Silica Coating NaYF4: Yb, Er@ NaYF4 Upconversion Nanoparticles Loaded with Ruthenium (II) Complex Nanoparticles: Fluorometric Sensing and Cellular Imaging of Temperature by Upconversion and of Oxygen by Downconversion. Microchim. Acta 2018, 185, 454-463. 50. Liu, Y.; Ai, K.; Lu, L. Designing Lanthanide-doped Nanocrystals with Both Up- and Downconversion Luminescence for Anti-counterfeiting. Nanoscale 2011, 3, 4804-4810. 51. Li, M.; Yao, W.; Liu, J.; Tian, Q.; Liu, L.; Ding, J.; Xue, Q.; Lu, Q.; Wu, W. Facile Synthesis and Screen Printing of Dual-mode Luminescent NaYF4:Er,Yb (Tm)/Carbon Dots for Anti-counterfeiting Applications. J. Mater. Chem. C 2017, 5, 6512-6520. 52. Ding, B.-B.; Peng, H.-Y.; Qian, H.-S.; Zheng, L.; Yu, S.-H. Unique Upconversion Coreshell Nanoparticles with Tunable Fluorescence Synthesized by A Sequential Growth Process. Adv. Mater. Interfaces 2016, 3, 1500649. 53. Wang, F.; Deng, R.; Liu, X. Preparation of Core-shell NaGdF4 Nanoparticles Doped with 40 ACS Paragon Plus Environment

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Langmuir

Luminescent Lanthanide Ions to Be Used as Upconversion-Based Probes. Nat. Protoc. 2014, 9, 1634-1644. 54. Zhu, S.; Meng, Q.; Wang, L.; Zhang, J.; Song, Y.; Jin, H.; Zhang, K.; Sun, H.; Wang, H.; Yang, B. Highly Photoluminescent Carbon Dots for Multicolor Patterning, Sensors, and Bioimaging. Angew. Chem. Int. Ed. 2013, 52, 3953-3957. 55. Du, G.; Song, Y.; Li, N.; Xu, L.; Tong, C.; Feng, Y.; Chen, T.; Xu, J. Cage-like hierarchically mesoporous hollow silica microspheres templated by mesomorphous polyelectrolyte-surfactant complexes for noble metal nanoparticles immobilization. Colloids Surf., A 2019, 575, 129-139. 56. Xu, X.; Li, W.; Zhou, W.; Tan, G.; Zheng, Y.; Hu, C.; Lei, B.; Zhang, X.; Liu, Y.; Zhuang, J. Preparation and Properties of Dual-mode Luminescent NaYF4:Yb,Tm@SiO2/Carbon Dot Nanocomposites. J. Mater. Chem. C 2018, 6, 10360-10366. 57. Kang, X.; Cheng, Z.; Li, C.; Yang, D.; Shang, M.; Ma, P. a.; Li, G.; Liu, N.; Lin, J. Core– shell

Structured

Up-conversion

Luminescent

and

Mesoporous

NaYF4:Yb3+/Er3+@nSiO2@mSiO2 Nanospheres as Carriers for Drug Delivery. J. Phys. Chem. C 2011, 115, 15801-15811. 58. Li, J. Y.; Liu, Y.; Shu, Q. W.; Liang, J. M.; Zhang, F.; Chen, X. P.; Deng, X. Y.; Swihart, M. T.; Tan, K. J. One-pot Hydrothermal Synthesis of Carbon Dots with Efficient Up-and Downconverted Photoluminescence for the Sensitive Detection of Morin in A Dual-readout Assay. Langmuir 2017, 33, 1043-1050. 59. Xie, S.; Tong, C.; Tan, H.; Li, N.; Gong, L.; Xu, J.; Xu, L,; Zhang, C. Hydrothermal Synthesis and Inkjet Printing of Hexagonal-phase NaYF4:Ln3+ Upconversion Hollow Microtubes for Smart Anti-counterfeiting Encryption. Mater. Chem. Front. 2018, 2, 19972005.


Upconversion nanoparticles@Carbon Dots@Meso-SiO2 Sandwiched

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