Fluorescent Microarrays of in Situ Crystallized Perovskite

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Fluorescent Microarrays of in-Situ Crystallized Perovskite Nanocomposites Fabricated for Patterned Applications by Using Inkjet Printing Yang Liu, Fushan Li, Lichun Qiu, Kaiyu Yang, Qianqian Li, Xin Zheng, Hailong Hu, Tailiang Guo, Chaoxing Wu, and Tae Whan Kim ACS Nano, Just Accepted Manuscript • DOI: 10.1021/acsnano.8b08582 • Publication Date (Web): 08 Feb 2019 Downloaded from http://pubs.acs.org on February 8, 2019

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Fluorescent Microarrays of in-Situ Crystallized Perovskite Nanocomposites Fabricated for Patterned Applications by Using Inkjet Printing

Yang Liu1, Fushan Li1,*, Lichun Qiu1, Kaiyu Yang1, Qianqian Li1, Xin Zheng1, Hailong Hu1, Tailiang Guo1, Chaoxing Wu2, and Tae Whan Kim2, *

1Institute

of Optoelectronic Technology, Fuzhou University, Fuzhou 350002, People’s Republic of China

2Department

of Electronic Engineering, Hanyang University, Seoul 133-791, Republic of Korea

Abstract Perovskite materials have exhibited promising potential for universal applications including backlighting, color conversion, and anti-counterfeiting labels fabricated using solution processes. However, owing to the tendency of those materials to have uncontrollable morphologies and to form large crystals, they cannot be utilized in discontinuous microminiaturization, which is crucial for practical optoelectronic applications. In this research, combining the effects of adding polyvinyl pyrrolidone (PVP), precisely controlling the inkjet printing technique, and using a post-processing procedure, we were able to fabricate in-situ crystallized perovskite-PVP nanocomposite microarrays with perfect morphologies. The viscosity of the perovskite precursor 1

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increased with the addition of PVP, eliminating the outward capillary flow that induces the coffee-ring effect. In addition, because of the presence of metallic bonds with the C=O groups in PVP and the spatial confinement of such a polymer, we were able to fabricate regulated CsPbBr3 nanocrystals capped with PVP and with a uniform size distribution. The as-printed patterns showed excellent homogeneity on a macro scale and high reproducibility on a micro scale; furthermore, those patterns were invisible in the ambient environment, compatible with flexible substrates, and cost efficient to produce, indicating that this technique holds promising potential for applications such as anti-counterfeiting labels. Keywords: perovskite nanocrystal; in-situ crystallization; inkjet printing; backlighting; anti-counterfeit label.

*Corresponding author: [email protected] (F. Li), [email protected] (T.W. Kim)

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For decades, solution-processed discontinuous microminiaturization has been attracting intense interest from researchers for its universal applications in full-color displays,1-3color painting,4 security labels,5 micro-lenses,6 and biological and chemical analyses.7 Inkjet printing, a non-contact mask-free material-effective technique that is compatible with multiple substrates, is the best candidate for such microminiaturization 3


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owing to its sophisticated ability to control size and location and to its reliable reproducibility with pre-designed patterns.8-15 Although inkjet printing is promising, the relative fluid kinetics and the drying process give rise to definite challenges, such as the need for multiple functional components, of which printable ink is an indispensable part. Recently, metal-halide perovskites have achieved tremendous success in solar cells and been extended to various applications, including light emitting diodes, photodetectors, lasers, and security labels, due to their impressive optoelectronic properties and facile solution-processability.16-25 In fact, the usefulness of a combination of inkjet printing and a perovskite material has been demonstrated; for example, perovskite films for solar cells have been printed with one-step and two-step methods.26-28 By using inkjet printing, Gu et al. fabricated in one chip perovskite singlecrystal arrays on large-scale and integrated perovskite microplates with red, green, and blue (RGB) emissions.29 Our group synthesized hybrid perovskite nanowires, microwires, networks, and islands by means of inkjet printing by using the proper solvent and controlling the crystal growth rate.30 In addition, through deposition on a pre-patterned substrate by using such a complicated technique as photolithography, perovskite arrays were successfully fabricated.31-33 However, these works are confined to morphologies with relatively large crystalline grains, which are beneficial for solar cells and photodetectors, but limit applications in fluorescent devices. To date, discontinuous microminiaturization of perovskite nanocrystals, which is definitely of 4


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great importance in optoelectronic applications, has not been explored. This can be attributed to the following two challenges: (1) In comparison with the dynamics of common spin coating, those of solutions and of crystallization in the inkjet printing process are quite different; that is, the thicker the precursor film is, the slower the evaporation rate is and the more restricted post-processing techniques, such as antisolvent film forming, are. (2) The intrinsic coffee-ring effect limits the morphology homogenization of inkjet-printed dots after total drying. Furthermore, inkjet printing of pre-synthesized perovskite quantum dots is a complicated, material-wasting, unstableink process. In this paper, for patterned fluorescent applications, we propose a facile strategy to fabricate discontinuous dot-constructed microminiaturized arrays of in-situ crystallized perovskite nanocomposites by using inkjet printing. We highlight the longchain polyvinyl pyrrolidone (PVP) additive to the perovskite precursor ink, which allows the realization of a reproducible spherical-cap-dot morphology and preferable perovskite crystallization. The viscosity of such ink increases with the addition of PVP, eliminating the outward capillary flow that induces the coffee-ring effect. Furthermore, because of the metallic bonds with the C=O groups in the PVP and the spatial confinement of such a polymer, regulated CsPbBr3 nanoparticles capped with PVP and exhibiting a uniform size distribution can be formed. Under UV light stimulation, these CsPbBr3/PVP nanocomposites emit bright green light with a fluorescent peak centered at 519 nm with a narrow full width at half maximum (FWHM) 5


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of 18 nm. Any well-designed patterns, such as the complicated logo of Fuzhou University, two-dimensional codes, and a honeybee pattern, can be fabricated easily based on this strategy. The as-printed patterns show homogeneous and bright fluorescence on a macro scale and a reproducible morphology on a micro scale; also, they are almost invisible in the ambient environment. In addition, the technique exhibits excellent compatibility with flexible substrates. Finally, the overall material cost per fluorescence image with 1000 dots is as low as 4.5 × 10-5 USA dollar. (See supplemental information.)

Results and Discussion Figure 1 depicts the in-situ crystallization process of perovskite nanocomposites fabricated by using the inkjet printing technique. The precursor ink for inkjet printing was prepared by adding cesium bromide (CsBr), lead bromide (PbBr2) and PVP into a solvent of dimethyl sulfoxide (DMSO). In this work, DMSO, which is characterized by a low evaporation rate and an outstanding dissolubility, was adopted as the solvent for ink preparation. Such an ink is transparent and stable in the ambient environment, without precipitation for several months, which is of great importance for industrialization (Figures 1a and S1). Then, the pre-prepared ink was inkjet printed on substrates via a high precision printer (Microfab JETLAB 2) equipped with a 60-μmdiameter piezoelectric-driven inkjet nozzle under stimulation by driving voltage waveforms (Figure S2) and with a motorized stage with an accuracy of 5 μm (Figure 6


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1b). After having been completely dried, each of the printed droplets represents a microscale fluorescent unit. The evaporation and the crystallization processes for a droplet are illustrated schematically in Figure 1c. Once the droplet reaches the substrate, the droplet forms a spherical cap in several microseconds, with the perovskite precursor and PVP long-chain molecules randomly distributed in it. Along with evaporation of DMSO, the PVP matrix shrinks and the residual precursor is divided by constructing many spatial barriers; then, the solutes in perovskite precursor are assembled in space. When the concentration of the perovskite precursor reaches its critical value for nucleation, CsPbBr3 nanocrystals are formed; these nanocrystals can be distinguished by their having a cubic lattice structure after final crystallization by vacuum drying at ambient temperature (Figure 1d). The in-situ synthesized CsPbBr3 nanocrystals are protected from deterioration originating from the ambient environment because they are capped with the PVP matrix. The high-resolution scanning electron microscopy (SEM) image and the corresponding particle-size distribution histogram (Figure 1e and Figure S3) confirm that PVP-capped rectangular CsPbBr3 nanocrystals with high crystallinity and a uniform size distribution (with a diameter of about 30 nm) are formed. The X-ray diffraction (XRD) spectra of pure PVP and the CsPbBr3/PVP nanocomposite, which are used as evidence for the crystallization of the perovskite nanocrystals, are shown in Figure 1f. The main diffraction peaks at 15.2º (100), 21.6º (110) and 30.5º (200) in the spectrum for the nanocomposite are identified as the characteristic peaks of CsPbBr3 nanocrystals, indicating that the CsPbBr3 nanocrystals are in a cubic phase, 7


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in contrast to the standard phase of CsPbBr3 (PDF#54-0752); this result is consistent with the results of other pioneering works.34, 35 In terms of fluorescent applications, perovskite crystals with smaller sizes are preferred because of their having higher fluorescent quantum yields. For the crystallization of halide perovskite materials, the final morphology is related to its nucleation and growth rate. Fast nucleation leads to a precursor concentration higher than the critical concentration for nucleation and produces a large number of nucleation agents; furthermore, the residual solutes for the following growth are consumed, thus yielding small particles. Slow nucleation, on the contrary, is liable to form a few embryonic seeds, resulting in the growth of larger crystals (Figure 2a).36-38 To date, several method, including the anti-solvent, designed growth template, and hightemperature annealing methods, have been developed to tailor the crystallization process.30, 39-41 Consequently, for perovskite-patterned fluorescent applications using the inkjet printing technique, a precursor ink that can achieve both high-quality printability and perovskite crystallization is desirable. Herein, we propose a strategy that fulfills the requirements for fabricating highquality perovskite-nanocrystal-based microminiaturized fluorescent arrays.

That

strategy uses the combined effects of using PVP as an additive, precisely controlling the inkjet printing technique, and using a post-processing procedure. We highlight the functionalities of the PVP polymer as an additive in tuning the printable properties of the ink, in controlling the perovskite crystallization process, and in determining the final 8


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morphology of the droplets. The CsPbBr3 precursor inks with PVP concentrations of 0, 100, 250, and 500 mg/ml have viscosities of 2.22, 7.66, 38.63, and 185.2 cP, respectively (Figure S4). For inks with PVP concentrations of 0 and 100 mg/ml, droplet formation and jetting stability can easily be realized; however, due to the intrinsically slow evaporation property of the droplets formed by using the inkjet printing technique, the crystal size is large and coffee-ring effects appear (Figures S5 and S6), even when substrate heating and vacuum drying are applied to accelerate the evaporation process. When the PVP concentration is raised to 250 and 500 mg/ml, however, the ink becomes unprintable (Figure S7). Considering that the viscosities of most polymer solutions decrease with increasing temperature, we tuned the nozzle temperature to improve the printability of the inks. For ink fabricated using 250 mg/ml of PVP, the viscosity decreased from 38.63 to 11.28 cP and a stable, single, flying droplet was obtained when the temperature was raised to 70°C (Figures S4b and S7). The 100×100 dot arrays with an interval of 200 μm were printed at nozzle temperatures of 30, 50 and 70°C. However, for temperatures of 30 and 50°C, the dot arrays were neither continuous nor uniform on a macro scale, indicating that the droplet formation and jetting was not stable. However, the morphologies of the perovskite arrays printed at a temperature of 70°C were perfect (Figure S8). Perfect perovskite crystallization and film morphology were obtained when we used a controllable post-processing procedure. The fluorescent pictures (Figures 2c19


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c6), along with the corresponding three-dimensional laser confocal microscope pictures (Figures 2d1-d6) and profile curves (Figures 2e1-e6) of the droplets evaporated in the ambient environment (about 20°C) and vacuum dried at 20, 30, 40, 50, and 60°C, showed CsPbBr3 crystals capped with the PVP matrix and droplet film morphology after final evaporation. If the droplets evaporate in the ambient environment at a slow solvent evaporation rate (with a boiling point of 189°C), the perovskite tends to form fewer, but larger, crystals, even with the addition of PVP. The reason could be that crystal nuclei appeared before the formation of the confined space constructed by PVP. Uniform, smooth dot profiles were obtained for droplets crystallized using vacuum drying at 20°C whereas the coffee-ring effect appeared when the substrate temperature was increased from 30 to 60°C. The following two factors originating from substrate heating may account for the mechanism behind such a coffee-ring effect. The acceleration of solvent evaporation with increasing temperature of the substrate leads to more vigorous capillary flow of the solution from the center to the periphery of the dot (Figure 2b); furthermore, the viscosity of the droplet decreases with rising temperature (Figure S4), most likely causing the PVP to be carried by the outward capillary flow. The spreading diameters of the droplets are almost identical, indicating that the wetting and the spreading properties of the droplets are insensitive to temperature (Figure S9). The reader should note that the temperature of the nozzle has minimal impact on the film’s morphology. After the droplet leaves the nozzle, thermal energy is consumed, and the temperature of the drop decreases to room temperature

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before it comes into contact with the substrate. The ensuing droplet capillary flow and film formation rely on the post process rather than nozzle heating. In order to clarify and confirm the mechanism of film formation, we studied the perovskite crystals and the morphologies of droplet films evaporated at different temperatures without vacuum drying. As expected, the coffee-ring effect worsened with increasing temperature (Figure S10), which is in agreement with the mechanism behind the formation of dot films. In addition, to demonstrate the advantage of this method, we prepared blue and red fluorescent dots by using inkjet printing and by partially replacing Br with Cl or I (Figure S11). The in-situ XRD curves recorded the evolution of CsPbBr3 nanocrystals capped with PVP matrix at temperatures from 25 to 300°C (Figure S12). The characteristic peaks of the nanocrystals were almost the same at temperatures below 150°C, indicating that the stabilities and the sizes were maintained in this temperature range. When temperature was increased to 200°C, the characteristic peaks became narrower, suggesting that the pre-synthesized CsPbBr3 nanocrystals capped with PVP matrix grew larger. The nanocrystals disappeared at 300°C, which was reflected by the disappearance of all the characteristic peaks. For the validation of the underlying confinement mechanism of the PVP on the surfaces of the CsPbBr3 nanocrystals, a comparison of the Fourier-transform infrared (FTIR) spectra of the PVP layer and the CsPbBr3/PVP nanocomposite are provided in Figure S13. The prominent absorption peak located at 1670 cm−1, corresponding to the 11


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functional C=O units in PVP, shifts to 1660 cm−1 for a polymer concentration of 250 mg/ml. This decrease in wave number for the C=O unit may be attributed to bond weakening as a result of back-bonding via partial lone pair electron donation from the oxygen in the PVP with Pb atoms on the surfaces of the CsPbBr3 nanocrystals and eventually passivates those surfaces.36 The X-ray photoelectron spectroscopy (XPS) spectra of the pure PVP matrix and the CsPbBr3 nanocrystals capped with the PVP matrix are shown in Figure S14. In comparison with the pure PVP matrix, the O1s peak shifts from 529.9 to 530.1 eV for the CsPbBr3/PVP nanocomposite, indicating bond interactions of the oxygen in the PVP with the perovskite nanocrystals, which is consistent with the FTIR results. In addition, XPS spectra of Cs, Pb and Br indicate the formation of CsPbBr3/PVP matrix further (Figure S15). The evolution of the photoluminescence (PL) spectra of the in-situ crystallization process for the CsPbBr3/PVP microarrays with 10000 PL units in total after inkjet printing is shown in Figure 3(a). The PL intensity of the CsPbBr3/PVP microarrays increases with time (1 min for one scanning turn). Such PL enhancement is attributed to the gradual consolidation of CsPbBr3 nanocrystals capped with PVP matrix.42 The final absorption and PL spectra of the CsPbBr3/PVP microarrays are shown in Figure 3(b). The as-synthesized CsPbBr3 nanocrystals capped with the PVP matrix exhibit an absorption peak at 509 nm and a PL peak centered at 519 nm. A Stokes shift from 509 nm to 519 nm exists between the emission and the band-edge absorption.43 In addition, the full width at half maximum (FWHM) of 18 nm suggests that the as-synthesized 12


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CsPbBr3 nanocrystals capped with the PVP matrix have a narrow size distribution. The time-resolved PL decay for the CsPbBr3 nanocrystals capped with the PVP matrix by using inkjet printing and for the CsPbBr3 crystals without the PVP additive, as well as the best fits to the corresponding tri-exponential fitting curves are depicted in Figure 3c. The average, the radiative, and the nonradiative PL lifetimes of CsPbBr3 nanocrystals capped with the PVP matrix are 38.74 ns, 60.2 ns, and 108.7 ns, respectively, and those of the CsPbBr3 crystals without the PVP additive are 45.45 ns, 483.5 ns, and 50.2 ns (Table S1). Compared to the CsPbBr3 crystals without PVP, for which the size histograms are shown in Figure S16, the average PL lifetime of the CsPbBr3 nanocrystals is shorter and the radiative rates are enhanced, which can be attributed to more efficient exciton recombination,41, 44 and is beneficial for fluorescent applications with PL quantum yield reaching 64.3 % (Table S1). The as-printed CsPbBr3/PVP microarrays are almost transparent (inset in Figure 3(d)) with a slight 10% decrease in the transmittance in visible spectral range (Figure 3(d)). To demonstrate the promising advantages of our strategy for large-scale, patterned and flexible applications, we present in Figure 4 in-situ inkjet-printed fluorescent CsPbBr3/PVP nanocomposite patterns constructed with a micro-scale dot array. In Figure 4a, the fluorescent image of the inkjet-printed macroscopic letters “FZU” is composed of green emission dot patterns with an interval distance of 200 μm and shows a homogeneous and bright fluorescence on a macro scale. Its enlarged fluorescence images and three-dimensional laser confocal microscope photographs demonstrate the 13


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excellent homogeneity and reproducibility of every single dot (Figures 4b-d). In addition, such a technique is suitable for any well-designed patterns, as was confirmed with the fluorescence images of the complicated logo of Fuzhou University and a honeybee pattern (Figures 4e, f). Furthermore, a two-dimensional code and bar code, composed of thousands of dot pixels, were realized and characterized with bright green fluorescence under UV light. All these patterns were transparent in the ambient environment, implying a promising application in anti-counterfeiting labels. The strategy also shows excellent compatibility with flexible substrates: the fluorescence images of the inkjet-printed logo of Fuzhou University on a flexible substrate and its local enlarged fluorescence image are identical with those of the logo on rigid substrates. This technique has also shown the prominent advantage of low fabrication cost. The overall material cost per fluorescence image with 1000 dots is estimated to be as low as approximately 4.5×10-5 USA dollar. (See Supplementary Note 1.)

Conclusions In conclusion, we were able to fabricate in-situ crystallized perovskitenanocomposite microarrays via inkjet printing by combining the effects of using a PVP additive, precisely controlling the inkjet printing process, and using a post-processing procedure. The viscosity of the perovskite precursor ink increased with the addition of PVP, which eliminated the outward capillary flow that induces the coffee-ring effect. In addition, owing to the metallic bonds with the C=O groups in PVP and the spatial 14


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confinement of the polymer, we were able to synthesize CsPbBr3 nanocrystals capped with PVP and with uniform size distribution. More importantly, this strategy can be extended to different color perovskite/PVP nanocomposites by introducing other halide components, such as I and Cl, into other space-confined polymers. The as-printed patterns showed excellent homogeneity on a macro scale and high reproducibility on a micro scale; moreover, they were invisible in the ambient environment, compatible with flexible substrates and cost-efficient to fabricate, indicating that this technique holds promise for applications such as anti-counterfeiting labels.

Experimental Section Chemicals: Cesium bromide (CsBr, 99.999%, Aladdin Reagent), PbBr2 (lead bromide, 99.999%, Aladdin Reagent), Polyvinylpyrrolidone (PVP, average Mw ~40,000 g mol-1, Sigma Aldrich), dimethyl sulfoxide (DMSO, 99.9%, Aladdin Reagent) were received and used without further purification. Device Fabrication: The perovskite CsPbBr3 precursor solution was prepared with a concentration of 0.1 M by dissolving 0.2-M CsBr and 0.1-M PbBr2 in DMSO solvent. The precursor solutions were stirred vigorously at 60°C for 12 h and then allowed to stand for 2 h. As a result, a CsBr-rich solution had formed, and the top transparent solution was decanted and filtered using a 0.22-μm polyvinyl difluoride syringe filter. For inkjet printing, 250 mg of PVP were added to the filtered precursors with different 15


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concentrations, and the resulting solutions were stirred vigorously at 60°C for 2 h. ITO-coated glass substrates were cleaned by ultrasonication successively in acetone, isopropanol and deionized (DI) water. The substrates were dried by using flowing nitrogen gas. The inkjet printing on the substrates was accomplished by using a Microfab JETLAB 2 printer equipped with a 60-μm-diameter piezoelectric-driven inkjet nozzle and a motorized stage with an accuracy of 5 μm. Characterization: The morphologies of the CsPbBr3/PVP microarrays were characterized by using a fluorescence microscope (Olympus, BX51M) and a threedimensional laser confocal microscope (Olympus, OLS4100). A Gmini300 unit was used to obtain high-resolution scanning electron microscope images to depict the CsPbBr3 nanocrystals. X-ray diffraction spectra were collected with an X'Pert PRO diffractometer (PANalytical). X-ray photoelectron spectroscopy (XPS) spectra were obtained using an ESCALAB 250 X-ray photoelectron spectrometer. Fourier-transform infrared (FTIR) spectra were recorded with a Nicolet 50 FTIR spectrometer at room temperature. The UV-Vis absorption spectra and the transmittance curves were acquired with a UV/Vis/NIR spectrophotometer (Shimadzu, UV-3600). The steadystate photoluminescence (PL) spectra were collected with a Hitachi F-4600 fluorescence spectrophotometer by exciting the samples using a Xe lamp coupled to a monochromator. Time-resolved PL measurements were performed using a fluorescence lifetime measurement system (HORIBA Scientific). The viscosities of the QD inks were obtained from a Brookfield Rotational Viscometer (DV2T) at room 16


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temperature. Supporting Information The Supporting Information is available free of charge on the ACS Publications website at DOI: xxx. Stability, viscosity evolution and spreading diameters of the inks, driving voltage of the nozzle, particle size distribution histogram for CsPbBr3 nanocrystals, PL spectra, PL microscope photographs, three-dimensional laser confocal microscope photographs, film thickness profiles, XRD curves, FTIR spectra, XPS spectra, and calculations of the radiative and the nonradiative lifetimes and cost in Figure S1-S16, Table S1 and Note S. Author information Yang Liu: 0000-0001-8809-0845 Fushan Li: 0000-0002-6074-2490 Chaoxing Wu: 0000-0002-1231-2699 Tae Whan Kim: 0000-0001-6899-4986

Acknowledgements This work was supported by the National Natural Science Foundation of China 17


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(U1605244) and by the National Key Research and Development Program of China (2016YFB0401305). This research was also supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2016R1A2A1A05005502).

Figure 1. In-situ crystallization of perovskite nanocomposites by inkjet printing. (a) Dissolution of the CsPbBr3/PVP composite ink in a solvent of DMSO for inkjet 18


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printing. (b) Inkjet printing process of the CsPbBr3/PVP composite ink. (c) Schematic illustrating the evaporation and the crystallization processes of the precursor ink. (d) CsPbBr3 nanocrystal lattice with a cubic crystal structure after final crystallization. (e) High-resolution scanning electron microscopy (SEM) image of the as-synthesized CsPbBr3 nanocrystals. (f) X-ray diffraction (XRD) curves of pure PVP and the CsPbBr3/PVP nanocomposite. The scale bar is 200 nm.

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Figure 2. Mechanistic investigation of the crystallization of the CsPbBr3 nanocrystals and the morphology of the inkjet-printed dots. (a) Schematic illustrating the crystallization process of the precursor ink under the conditions of faster nucleation and slower nucleation. (b) Schematic of the evaporation and the deposition processes for the droplet. (c1-c6) PL microscope photographs, (d1d6) three-dimensional laser confocal microscope photographs and (e1-e6) film thickness profiles of each single dot crystallized in an ambient environment and vacuum dried with substrate temperatures of 20, 30, 40, 50, and 60°C. (The scale bar is 50 μm)

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Figure 3. Optical properties of in-situ crystallized CsPbBr3/PVP nanocomposite microarrays. (a) Evolution of the photoluminescence (PL) spectra of CsPbBr3/PVP microarrays with time after inkjet printing. (b) Absorption and PL spectra of final CsPbBr3/PVP microarrays. (c) Time-resolved PL decays and corresponding tri-exponential fits for CsPbBr3/PVP fabricated and for the CsPbBr3 crystals without PVP using inkjet printing. (d) Transmittance spectra of ITO-coated glass substrates with and without inkjet printing of CsPbBr3/PVP microarrays (Inset: photographs of the CsPbBr3/PVP microarrays

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light).

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Figure 4. In situ, inkjet-printed, fluorescent CsPbBr3/PVP nanocomposite patterns with dot-constructed microarrays. (a) Typical fluorescent image of the inkjet-printed macroscopic letters “FZU” composed of green emission dot patterns, coupled with (b, c) a local enlarged fluorescence image and (d) a three-dimensional laser confocal microscope photograph. Fluorescence images of the complicated (e) Fuzhou University logo and (f) honeybee pattern. (g) Two-dimensional code and bar code composed of thousands of dot-pattern pixels. (h) Fluorescence images of the inkjet-printed Fuzhou University logo on a flexible substrate and its local enlarged fluorescence image. Panels (e) and (h) are 22


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adapted with permission colorized versions of the logo of the Fuzhou University.

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References 1.

Kim, T. H.; Cho, K. S.; Lee, E. K.; Lee, S. J.; Chae, J.; Kim, J. W.; Kim, D. H.;

Kwon, J.-Y.; Amaratunga, G.; Lee, S. Y.; Choi, B. L.; Kuk, Y.; Kim, J. M.; Kim, K. Full-Colour Quantum Dot Displays Fabricated by Transfer Printing. Nat. Photonics 2011, 5, 176-182. 2.

Liu, Y.; Li, F.; Xu, Z.; Zheng, C.; Guo, T.; Xie, X.; Qian, L.; Fu, D.; Yan, X.

Efficient All-Solution Processed Quantum Dot Light Emitting Diodes Based on Inkjet Printing Technique. ACS Appl. Mater. Interfaces 2017, 9, 25506-25512. 3.

Wood, V.; Panzer, M. J.; Chen, J. L.; Bradley, M. S.; Halpert, J. E.; Bawendi, M.

C.; Bulovic, V. Inkjet-Printed Quantum Dot-Polymer Composites for Full-Color AcDriven Displays. Adv. Mater. 2009, 21, 2151-2155. 4.

Bai, L.; Mai, V.; Lim, Y.; Hou, S.; Mohwald, H.; Duan, H. W. Large-Scale

Noniridescent Structural Color Printing Enabled by Infiltration-Driven Nonequilibrium Colloidal Assembly. Adv. Mater. 2018, 30, 1705667. 5.

Keller, K.; Yakovlev, A. V.; Grachova, E. V.; Vinogradov, A. V. Inkjet Printing of

Multicolor Daylight Visible Opal Holography. Adv. Funct. Mater. 2018, 28, 1706903. 6.

Zhou, X. T.; Peng, Y. Y.; Peng, R.; Zeng, X. Y.; Zhang, Y. A.; Guo, T. L.

Fabrication of Large-Scale Microlens Arrays Based on Screen Printing for Integral Imaging 3d Display. ACS Appl. Mater. Interfaces 2016, 8, 24248-24255.

24


Page 24 of 33

Page 25 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

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7.

Feng, W. Q.; Ueda, E.; Levkin, P. A. Droplet Microarrays: From Surface Patterning

to High-Throughput Applications. Adv. Mater. 2018, 30, 1706111. 8.

Bormashenko, E. Progress in Understanding Wetting Transitions on Rough

Surfaces. Adv. Colloid Interface Sci. 2015, 222, 92-103. 9.

Li, D. D.; Lai, W. Y.; Zhang, Y. Z.; Huang, W. Printable Transparent Conductive

Films for Flexible Electronics. Adv. Mater. 2018, 30, 1704738. 10. Minemawari, H.; Yamada, T.; Matsui, H.; Tsutsumi, J.; Haas, S.; Chiba, R.; Kumai, R.; Hasegawa, T. Inkjet Printing of Single-Crystal Films. Nature 2011, 475, 364-367. 11. Hu, G. H.; Albrow-Owen, T.; Jin, X. X.; Ali, A.; Hu, Y. W.; Howe, R. C. T.; Shehzad, K.; Yang, Z. Y.; Zhu, X. K.; Woodward, R. I.; Wu, T. C.; Jussila, H.; Wu, J. B.; Peng, P.; Tan, P. H.; Sun, Z. P.; Kelleher, E. J. R.; Zhang, M.; Xu, Y.; Hasan, T. Black Phosphorus Ink Formulation for Inkjet Printing of Optoelectronics and Photonics. Nat. Commun. 2017, 8, 278. 12. Jiang, H.; Kaminska, B. Scalable Inkjet-Based Structural Color Printing by Molding Transparent Gratings on Multilayer Nanostructured Surfaces. ACS nano 2018, 12, 3112-3125. 13. Kang, H.; Lee, G. H.; Jung, H.; Lee, J. W.; Nam, Y. Inkjet-Printed Biofunctional Thermo-Plasmonic Interfaces for Patterned Neuromodulation. ACS nano 2018, 12, 1128-1138.

25


ACS Nano 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

14. Kuang, M. X.; Wang, J. X.; Bao, B.; Li, F. Y.; Wang, L. B.; Jiang, L.; Song, Y. L. Inkjet Printing Patterned Photonic Crystal Domes for Wide Viewing-Angle Displays by Controlling the Sliding Three Phase Contact Line. Adv. Opt. Mater. 2014, 2, 34-38. 15. Han, W.; Lin, Z. Learning from "Coffee Rings": Ordered Structures Enabled by Controlled Evaporative Self-Assembly. Angew. Chem., Int. Ed. 2012, 51, 1534-46. 16. Brittman, S.; Luo, J. S. A Promising Beginning for Perovskite Nanocrystals: A Nano Letters Virtual Issue. Nano Lett. 2018, 18, 2747-2750. 17. Arora, N.; Dar, M. I.; Hinderhofer, A.; Pellet, N.; Schreiber, F.; Zakeeruddin, S. M.; Gratzel, M. Perovskite Solar Cells with Cuscn Hole Extraction Layers Yield Stabilized Efficiencies Greater Than 20%. Science 2017, 358, 768-771. 18. Abdi-Jalebi, M.; Andaji-Garmaroudi, Z.; Cacovich, S.; Stavrakas, C.; Philippe, B.; Richter, J. M.; Alsari, M.; Booker, E. P.; Hutter, E. M.; Pearson, A. J.; Lilliu, S.; Savenije, T. J.; Rensmo, H.; Divitini, G.; Ducati, C.; Friend, R. H.; Stranks, S. D. Maximizing and Stabilizing Luminescence from Halide Perovskites with Potassium Passivation. Nature 2018, 555, 497. 19. Chen, Q. S.; Wu, J.; Ou, X. Y.; Huang, B. L.; Almutlaq, J.; Zhumekenov, A. A.; Guan, X. W.; Han, S. Y.; Liang, L. L.; Yi, Z. G.; Li, J.; Xie, X. J.; Wang, Y.; Li, Y.; Fan, D. Y.; Teh, D. B. L.; All, A. H.; Mohammed, O. F.; Bakr, O. M.; Wu, T.; et al. All-Inorganic Perovskite Nanocrystal Scintillators. Nature 2018, 561, 88. 20. Veldhuis, S. A.; Boix, P. P.; Yantara, N.; Li, M. J.; Sum, T. C.; Mathews, N.; 26


Page 26 of 33

Page 27 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Nano

Mhaisalkar, S. G. Perovskite Materials for Light-Emitting Diodes and Lasers. Adv. Mater. 2016, 28, 6804-6834. 21. Zhang, C. Y.; Wang, B.; Li, W. B.; Huang, S. Q.; Kong, L.; Li, Z. C.; Li, L. Conversion of Invisible Metal-Organic Frameworks to Luminescent Perovskite Nanocrystals for Confidential Information Encryption and Decryption. Nat. Commun. 2017, 8, 1138. 22. Cao, Y.; Wang, N.; Tian, H.; Guo, J.; Wei, Y.; Chen, H.; Miao, Y.; Zou, W.; Pan, K.; He, Y. Perovskite Light-Emitting Diodes Based on Spontaneously Formed Submicrometre-Scale Structures. Nature 2018, 562, 249. 23. Lin, K.; Xing, J.; Quan, L. N.; de Arquer, F. P. G.; Gong, X.; Lu, J.; Xie, L.; Zhao, W.; Zhang, D.; Yan, C. Perovskite Light-Emitting Diodes with External Quantum Efficiency Exceeding 20 Per Cent. Nature 2018, 562, 245. 24. Gu, Z.; Huang, Z.; Li, C.; Li, M.; Song, Y. A General Printing Approach for Scalable Growth of Perovskite Single-Crystal Films. Sci. Adv. 2018, 4, eaat2390. 25. He, M.; Li, B.; Cui, X.; Jiang, B.; He, Y.; Chen, Y.; O'Neil, D.; Szymanski, P.; ElSayed, M. A.; Huang, J.; Lin, Z. Meniscus-Assisted Solution Printing of Large-Grained Perovskite Films for High-Efficiency Solar Cells. Nat. Commun. 2017, 8. 26. Hashmi, S. G.; Martineau, D.; Li, X.; Ozkan, M.; Tiihonen, A.; Dar, M. I.; Sarikka, T.; Zakeeruddin, S. M.; Paltakari, J.; Lund, P. D.; Gratzel, M. Air Processed Inkjet Infiltrated Carbon Based Printed Perovskite Solar Cells with High Stability and 27


ACS Nano 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Reproducibility. Adv. Mater. Technol. 2017, 2, 1600183. 27. Liang, C.; Li, P. W.; Gu, H.; Zhang, Y. Q.; Li, F. Y.; Song, Y. L.; Shao, G. S.; Mathews, N.; Xing, G. C. One-Step Inkjet Printed Perovskite in Air for Efficient Light Harvesting. Sol. RRL 2018, 2, 1700217. 28. Li, P. W.; Liang, C.; Bao, B.; Li, Y. N.; Hu, X. T.; Wang, Y.; Zhang, Y. Q.; Li, F. Y.; Shao, G. S.; Song, Y. L. Inkjet Manipulated Homogeneous Large Size Perovskite Grains for Efficient and Large-Area Perovskite Solar Cells. Nano Energy 2018, 46, 203-211. 29. Gu, Z. K.; Wang, K.; Li, H. Z.; Gao, M.; Li, L. H.; Kuang, M. X.; Zhao, Y. S.; Li, M. Z.; Song, Y. L. Direct-Writing Multifunctional Perovskite Single Crystal Arrays by Inkjet Printing. Small 2017, 13, 1603217. 30. Liu, Y.; Li, F. S.; Veeramalai, C. P.; Chen, W.; Guo, T. L.; Wu, C. X.; Kim, T. W. Inkjet-Printed Photodetector Arrays Based on Hybrid Perovskite Ch3nh3pbi3 Microwires. ACS Appl. Mater. Interfaces 2017, 9, 11662-11668. 31. Wang, G.; Li, D.; Cheng, H.-C.; Li, Y.; Chen, C.-Y.; Yin, A.; Zhao, Z.; Lin, Z.; Wu, H.; He, Q. J. S. a. Wafer-Scale Growth of Large Arrays of Perovskite Microplate Crystals for Functional Electronics and Optoelectronics. Sci. Adv. 2015, 1, e1500613. 32. Lee, W.; Lee, J.; Yun, H.; Kim, J.; Park, J.; Choi, C.; Kim, D. C.; Seo, H.; Lee, H.; Yu, J. W.; Lee, W. B.; Kim, D. H.. High-Resolution Spin-on-Patterning of Perovskite Thin Films for a Multiplexed Image Sensor Array. Adv. Mater. 2017, 29. 28


Page 28 of 33

Page 29 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

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33. Wu, J.; Ye, F.; Yang, W.; Xu, Z.; Luo, D.; Su, R.; Zhang, Y.; Zhu, R.; Gong, Q. J. C. o. M. Perovskite Single-Crystal Microarrays for Efficient Photovoltaic Devices. Chem. Mater. 2018, 30, 4590-4596. 34. Wang, H. C.; Lin, S. Y.; Tang, A. C.; Singh, B. P.; Tong, H. C.; Chen, C. Y.; Lee, Y. C.; Tsai, T. L.; Liu, R. S. Mesoporous Silica Particles Integrated with All-Inorganic CsPbBr3 Perovskite Quantum-Dot Nanocomposites (Mp-Pqds) with High Stability and Wide Color Gamut Used for Backlight Display. Angew. Chem., Int. Ed. 2016, 55, 79247929. 35. Protesescu, L.; Yakunin, S.; Bodnarchuk, M. I.; Krieg, F.; Caputo, R.; Hendon, C. H.; Yang, R. X.; Walsh, A. Kovalenko, M. V., Nanocrystals of Cesium Lead Halide Perovskites (Cspbx3, X = Cl, Br, and I): Novel Optoelectronic Materials Showing Bright Emission with Wide Color Gamut. Nano Lett. 2015, 15, 3692-3696. 36. Soltani, N.; Saion, E.; Erfani, M.; Rezaee, K.; Bahmanrokh, G.; Drummen, G. P. C.; Bahrami, A.; Hussein, M. Z. Influence of the Polyvinyl Pyrrolidone Concentration on Particle Size and Dispersion of Zns Nanoparticles Synthesized by Microwave Irradiation. Int. J. Mol. Sci. 2012, 13, 12412-12427. 37. Saidaminov, M. I.; Abdelhady, A. L.; Maculan, G.; Bakr, O. M. Retrograde Solubility of Formamidinium and Methylammonium Lead Halide Perovskites Enabling Rapid Single Crystal Growth. Chem. Commun. 2015, 51, 17658-17661. 38. Xiao, Z. G.; Kerner, R. A.; Zhao, L. F.; Tran, N. L.; Lee, K. M.; Koh, T. W.; 29


ACS Nano 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Scholes, G. D.; Rand, B. P. Efficient Perovskite Light-Emitting Diodes Featuring Nanometre-Sized Crystallites. Nat. Photonics 2017, 11, 108-115. 39. Chen, Y. N.; He, M. H.; Peng, J. J.; Sun, Y.; Liang, Z. Q. Structure and Growth Control of Organic-Inorganic Halide Perovskites for Optoelectronics: From Polycrystalline Films to Single Crystals. Adv. Sci. 2016, 3, 1500392. 40. Jeon, N. J.; Noh, J. H.; Kim, Y. C.; Yang, W. S.; Ryu, S.; Il Seol, S. Solvent Engineering for High-Performance Inorganic-Organic Hybrid Perovskite Solar Cells. Nat. Mater. 2014, 13, 897-903. 41. Malgras, V.; Tominaka, S.; Ryan, J. W.; Henzie, J.; Takei, T.; Ohara, K. Yamauchi, Y., Observation of Quantum Confinement in Monodisperse Methylammonium Lead Halide Perovskite Nanocrystals Embedded in Mesoporous Silica. J. Am. Chem. Soc. 2016, 138, 13874-13881. 42. Zhou, Q. C.; Bai, Z. L.; Lu, W. G.; Wang, Y. T.; Zou, B. S.; Zhong, H. Z. In Situ Fabrication of Halide Perovskite Nanocrystal-Embedded Polymer Composite Films with Enhanced Photoluminescence for Display Backlights. Adv. Mater. 2016, 28, 91639168. 43. Brennan, M. C.; Zinna, J.; Kuno, M. Existence of a Size-Dependent Stokes Shift in CsPbBr3 Perovskite Nanocrystals. ACS Energy Lett. 2017, 2, 1487-1488. 44. Li, Y. X.; Huang, H.; Xiong, Y.; Kershaw, S. V.; Rogach, A. L. Revealing the Formation Mechanism of CsPbBr3 Perovskite Nanocrystals Produced Via a Slowed30


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Down Microwave-Assisted Synthesis. Angew. Chem., Int. Ed. 2018, 57, 5833-5837.

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For Table of Contents Only Fluorescent Microarrays of in-Situ Crystallized Perovskite Nanocomposites Fabricated for Patterned Applications by Using Inkjet Printing Yang Liu1, Fushan Li1,*, Lichun Qiu1, Kaiyu Yang1, Qianqian Li1, Xin Zheng1, Hailong Hu1, Tailiang Guo1, Chaoxing Wu2, and Tae Whan Kim2, *

Perovskite materials have exhibited promising potential for universal applications including backlighting, color conversion, and anti-counterfeiting labels fabricated using solution processes. However, owing to the tendency of those materials to have uncontrollable morphologies and to form large crystals, they cannot be utilized in discontinuous microminiaturization, which is crucial for practical optoelectronic applications. In this research, combining the effects of adding polyvinyl pyrrolidone (PVP), precisely controlling the inkjet printing technique, and using a post-processing procedure, we were able to fabricate in-situ crystallized perovskite-PVP nanocomposite microarrays with perfect morphologies. The viscosity of the perovskite precursor increased with the addition of PVP, eliminating the outward capillary flow that induces the coffee-ring effect. In addition, because of the presence of metallic bonds with the C=O groups in PVP and the spatial confinement of such a polymer, we were able to fabricate regulated CsPbBr3 nanocrystals capped with PVP and with a uniform size distribution. The as-printed patterns showed excellent homogeneity on a macro scale and high reproducibility on a micro scale; furthermore, those patterns were invisible in 32


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the ambient environment, compatible with flexible substrates, and cost efficient to produce, indicating that this technique holds promising potential for applications such as anti-counterfeiting labels.

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Fluorescent Microarrays of in Situ Crystallized Perovskite

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