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Multicolor photoluminescence of a hybrid film via dualemitting strategy of inorganic fluorescent Au nanocluster and organic room-temperature phosphorescent copolymer Xi Wang, Yun Xu, Xiang Ma, and He Tian Ind. Eng. Chem. Res., Just Accepted Manuscript • DOI: 10.1021/acs.iecr.7b04759 • Publication Date (Web): 07 Feb 2018 Downloaded from http://pubs.acs.org on February 7, 2018
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Multicolor photoluminescence of a hybrid film via dual-emitting strategy of inorganic fluorescent Au nanocluster and organic room-temperature phosphorescent copolymer Xi Wang, Yun Xu, Xiang Ma* and He Tian* Key Laboratory for Advanced Materials and Institute of Fine Chemicals, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, China.
ABSTRACT: Achieving multicolor photoluminescence, especially white-light emission, under mild conditions based on hybrid organic-inorganic materials has attracted growing attention. A novel system, via histidine modified Au nanocluster (AuNC@histidine) with bluish green fluorescence and a 4-bromo-1,8-naphthalicanhydride derivative polymer (poly-BrNpA) with orange room-temperature phosphorescence (RTP) emission, were designed and prepared. White-light emission could be achieved by adjusting the proportions of the two components. The hydrogen bond made the RTP emission of such copolymer systems be enhanced through suppressing the nonradiative relaxation process by the well-formed and highly cross-linked network. By introducing fluorescence compounds
(AuNC@histidine)
which
was
insensitive
to
environmental
humidity,
this
fluorescence-phosphorescence dual-emitting hybrid system could also be used as a humidity responsive material, since the hydrogen bonds in poly-BrNpA chains could be broken by environmental humidity. The color switching could be well conducted in poly(vinyl alcohol) (PVA) matrix, which was good for forming a processable and humidity responsive film.
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1. INTRODUCTION
Over the last few decades, gold hybrid organic–inorganic materials have been fruitfully reported. Designing monolayer protected gold clusters has brought about a remarkable development in the field of functional materials, whose properties were dependent on the size and shape of metal nanoparticles1, 2. It is now possible to control the properties of metal particles by modifying their surfaces with a monolayer of organic molecules (ligands)3, 4. An attractive aspect of recent development is that gold nanoclusters (AuNCs) with size below 2 nm are endowed with fluorescence emission since they are almost somewhat molecule-like and possess interesting and size-dependent properties including optical absorption and quantized electrical charging5-8. Owing to their facile preparation, high photostability and easy functionalization, fluorescent AuNCs integrated into different host materials could be used as functional materials in chemical sensing and optical applications.
Among
various
photoluminescence
(PL)
materials,
pure
organic
room-temperature
phosphorescence (RTP) materials have also attracted growing attention because of their unique generation process and long-lived luminescence. RTP materials are mainly metal coordination complexes and crystallization-induced organic phosphorescence compounds9-15. However, it should be noted that the character of toxic organometallic compounds and strict growth conditions of crystallization restrict the development of RTP materials. Afterwards some metal-free amorphous RTP materials were reported. The usual method to obtain these materials was to embed pure organic phosphors into a polymer matrix16-19, steroidal compounds20, 21, the cavity of macrocycle hosts22-26, supramolecular gels27, 28, and so forth. As such, the partial preparation condition are limited with deuterium substitution, deuterium oxide as reactant and drop-casting then thermally annealing at high temperature under nitrogen atmosphere. Therefore, further explorations of a more facile 2
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strategy to get efficient pure organic amorphous RTP materials in air are necessary. We have recently reported
a
simple
metal-free
amorphous
phosphore
copolymer
which
exhibited
the
advantages of facile preparation and efficient RTP emission22.
Meanwhile, a part of strategies based on multiple component systems have been proposed to produce white-light emission. For example, a novel three component system consisting of gold cluster, riboflavin and rhodamine B genarating white-light emission via the energy transfer mechanism has been reported previously29. However, it is very rare to introduce fluorescent noble metal clusters into fluorescence-phosphorescence (F-P) hybrid system to realize tunable multicolor photoluminescence emission especially white-light one by humidity change.
Herein, after combining fluorescent AuNCs (AuNC@histidine) with bluish green fluorescence emission and RTP polymer with orange room-temperature phosphorescence emission (by a radical binary copolymerization employing acrylamide and a 4-bromo-1,8-naphthalicanhydride derivative, poly-BrNpA) into poly(vinyl alcohol) (PVA), the hybrid system could realize multicolor emission between red and green even white-light (CIE coordinates = 0.33, 0.32) by adjusting the ratio (Scheme 1). The hydrogen bond linking polymer chains help to immobilize the RTP phosphors and shield part of the phosphorescence from oxygen to certain degree. Through suppressing the nonradiative relaxation process by the well-formed and highly cross-linked network, the RTP emission of such copolymer systems could be enhanced30. In addition, a humidity responsive material has been constructed, since the hydrogen bonding between polymeric chains enhancing RTP emission could be broken by adding water. This new dual-emission hybrid material supplies a novel method to generate multicolor and humidity-responsive luminescence.
Scheme 1. Preparation of the poly-BrNpA-AuNC@histidine-PVA composite film. 3
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2. EXPERIMENTAL SECTION
Materials. All reagents are commercially available and used as supplied without further purification. Solvents were purified according to standard laboratory methods. The molecular structures were confirmed by using 1H NMR, 13C NMR and high-resolution ESI mass spectroscopy. The structures and synthesis of the key intermediates see in Supporting Information (SI).
Synthesis of 2-(4-aminobutyl)-6-bromo-1H-benzo [de]isoquinoline-1,3(2H)-dione. (1) The 2-(4-aminobutyl)-6-bromo-1H-benzo [de]isoquinoline-1,3(2H)-dione was synthesized according to literature procedure31.
Synthesis of N-(4-(6-bromo-1, 3-dioxo-1 H-benzo [de]isoquinolin-2(3H)-yl) butyl) acrylamide (2) and poly-BrNpA. (3) Both compound 2 and 3 were synthesized according to previous report22. Briefly, The compound 1 (0.50 g, 1.44 mmol, 1 eq) and triethylamine (0.22 g, 2.16 mmol, 1.5 eq) were dissolved in dried dichloromethane and cooled with ice-water baths. Acryloyl chloride (0.16 g, 1.73 mmol, 1.2 eq) was added dropwise with a syringe under an argon atmosphere. After removing
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the ice-water baths, the mixture was stirred for 5 h at room temperature. The solution was concentrated and purified by column chromatography (petroleum ether/ethyl acetate, 1/1, v/v) to afford a white solid (0.41 g, 71 % yield). The polymer was prepared by copolymerization of the compound 2 (0.050 g, 0.125 mmol, 1 eq) and
acrylamide
(0.443
g,
6.230
mmol,
50
eq)
by
a
radial
polymerization
with
2,2'-azobis(2-methylpropionitrile) (AIBN) (0.0021 g, 0.0125 mmol, 0.1 eq) as radical initiator at 65 ℃ under an argon atmosphere in DMF for 12 h. The resulting mixture was added into methanol to precipitate the polymeric materials. Precipitation was repeatedly washed with methanol to give purified polymers.
Preparation of AuNC@histidine. AuNC@histidine was synthesized according to the method reported by Chen et al32. Atomic gold clusters (Au10) were synthesized in a facile blending manner. Typically, an aqueous solution of HAuCl4 (1 mL, 10 mM) was mixed with an aqueous solution of histidine (3 mL, 0.1 M) in a small vial at room temperature. The color of the solution turned pale yellow immediately, indicating the formation of Au10 clusters. The mixture was incubated for 2 h for further characterization.
Preparation of poly-BrNpA-AuNC@histidine-PVA composite. The composite was prepared by mixing the PVA (0.14g, Mw=1750±50), polymer 3 (0.001 g, 0.0025 mmol) and AuNC@histidine (0-1400μl, 8.4mg/ml) in the deionized water (detailed data see Table S1), and then stirring for 15 minutes at room temperature. A centrifuge method was adopted to avoid bubbles and then stand for 1 hour. Such obtained PVA solution are smeared on glass to prepare PVA films by natural withering. Measurements and characterization. 1H NMR and
13
C NMR spectra were measured on a
Brüker AV-400 spectrometer. The electronic spray ionization (ESI) high-resolution mass spectra were tested on a Waters LCT Premier XE spectrometer. The UV–Vis measurements were collected 5
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on an Agilent Technologies Cary 60 UV–Vis spectrophotometer between 200 and 800 nm. Transmission electron microscopy (TEM) characterization was carried out by a JEOL JEM-2100 TEM under an accelerating voltage of 100 kV. Samples were prepared by applying two drops of the aqueous AuNC@histidine solution onto an ultrathin carbon coated copper TEM grid (200 mesh) which was produced by Zhongxingbairui Technology Corporation. Dual-emitting spectra, fluorescence spectra, RTP spectra, lifetime and Quantum yields were recorded on an HORIBA Fluoromax-4 spectrofluorometer. Poly-BrNpA was prepared via radical binary copolymerization by employing acrylamide and RTP phosphors 4-bromo-1,8-naphthalic anhydride, respectively.
3. RESULTS AND DISCUSSIONS
The characterization of AuNC@histidine. The gold cluster was characterized by UV–Vis, TEM and fluorescence spectra. UV-Vis spectroscopic studies were performed to obtain the individual absorption spectrum of AuNCs. UV-Vis spectra of HAuCl4 and AuNC@histidine were studied and shown in Figure 1a, which was similar with previous report32. Because of its molecular-like properties, AuNCs exhibited a broad absorption band around 265 nm. It was different from HAuCl4 which had a distinct peaks in its absorption spectrum at 320 nm, and from AuNPs which had a broad peaks of characteristic surface plasma resonance (SPR)33. All these experiments were conducted in aqueous solutions. TEM imaging was performed to obtain the crucial information on the dispersity and average particle size of the AuNC@histidine. But the fluorescent gold nanoclusters (AuNCs) size were less than 1nm, which were difficult to be captured with high power transmission electron microscope. The TEM images of the clusters were shown in Figure S2 (Supporting Information). The fluorescent spectroscopic studies were performed to depict the gold clusters emitters. This aqueous AuNCs solution emitted strong bluish green fluorescence (Figure 1b) under UV irradiation 6
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(at 365 nm), and the maximum emission was at 475 nm (Figure 1a) by 340 nm optical excitation. This was also supported by obtaining a green fluorescent solution when the solution of the gold cluster was exposed to the UV irradiation at 365 nm. And the aqueous AuNC solution reached a relatively high fluorescence quantum yield (QY) of 0.49%, while the QYs of other thiolated metal NCs rarely exceed 0.1%34.
Figure 1. a) The UV-Vis absorption spectra of HAuCl4 (black line) and AuNCs (AuNC@histidine) (red line); Photoluminescence spectrum of the AuNC@histidine in aqueous under λ=340 nm UV irradiation (dotted line); b) The photos of HAuCl4 (left) and AuNC@histidine (right) under sunlight and UV light (365nm) (10-3M); c) The UV-vis absorption spectra (black line) and RTP spectrum (dotted line) of poly-BrNpA in the amorphous solid state; d) Photographs of the solid powder of poly-BrNpA under 365nm UV light (above) and sunlight (below), respectively.
The characterization of poly-BrNpA. A radical binary copolymerization according to literature procedure was used in the preparation of poly-BrNpA, employing acrylamide and a 4-bromo-1,8-naphthalic anhydride derivative (the ratio of the two monomers was 50:1)22, 30. 7
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The spectroscopic RTP emission studies of poly-BrNpA were thoroughly performed. A strong emission peak at 580nm excited under UV irradiation of 365nm at room temperature had a quantum yield of 7.1% (shown in Figure 1c). The fluorescence emission of these phosphors was weak and negligible due to the heavy atom effect of the bromo moieties. Supported by the above information, an orange phosphorescent amorphous solid powder was obtained. The hydrogen bond linking polymer chains might immobilize the RTP phosphors and shield part of the phosphorescence from oxygen quencher to certain degree. Through suppressing the nonradiative relaxation process by the well-formed and highly cross-linked network, the RTP emission of such copolymer systems could be effectively enhanced30. Besides, the hydrogen bonding between BrNpA polymer chains enhancing RTP emission could be broken by adding water, thus led to the phosphorescence quenching22.
The fluorescence spectra of aqueous AuNC@histidine-PVA and AuNC@histidine-PVA composite film. The optical properties of the AuNC@histidine in solution and PVA matrix were thoroughly examined. AuNC@histidine in aqueous solution revealed a general luminescent behavior, showing that the wavelength of the emission light increased along with the wavelength of the excited light increase (Figure 2a). The maximum emission wavelength is 505nm with irradiated excitation at 400 nm. A dispersion of AuNC@histidine in an aqueous PVA solution had similar luminescent properties. The λmax was also at 505 nm (excited at 400nm). However, it occurred a certain loss of emission intensity about 90% of the original (Figure 2b).
For the PVA film of AuNC@histidine, its character was quite different from the solution state (Figure 2c). A hypsochroic shift of λmax from 505nm to 495nm was observed compared with the dispersion in solution state. With the increase of excitation wavelength, the blue shift was more obvious (the maximum hypsochroic shift was about 70nm with the excitation wavelength at 300nm). As PVA chains were soluble in aqueous solution, the AuNC@histidine was well dispersed in 8
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solution. Along with the volatilization of water, the hydrogen bond between the PVA chains would generate gradually. The hydrogen bond could not only fix the gold clusters, but also made the distance shorter, resulting in a hypsochroic shift of luminescence. Besides, the luminous intensity occurred a further loss of emission intensity to about 80% of the original.
Figure 2. Photoluminescence spectra of a) the AuNC@histidine in aqueous solution; b) the aqueous AuNC@histidine-PVA; and c) the AuNC@histidine-PVA composite film under UV 9
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irradiation with the excitation wavelength of 300nm-450nm (with the wavelength difference between the neighbored spectra 10 nm). The red dots show the variation trends of λmax of the emission.
White-light emission of the triadic film. To explore the interplay and color change between poly-BrNpA
and
AuNC@histidine,
we
prepared
a
novel
triadic
film
poly-BrNpA-AuNC@histidine-PVAs with different molar proportions of the two luminophors (specific data see Table S1). The adopted ratios (w/w) of poly-BrNpA/AuNC@histidine were 1:0, 1:0.84, 1:1.68, 1:2.52, 1:3.36, 1:4.2, 1:5.06, 1:5.88, 1:6.72, 1:7.56, 1:8.4, 1:9.24, 1:10.08, 1:10.08, and 0:11.76, respectively. By mixing different ratios of poly-BrNpA and AuNC@histidine, the change of PL spectra and CIE coordinates were tested and shown in Figure 3a.
The intramolecular FRET of a complex is often due to the inclusion between different luminophores, resulting in enhanced emission of the energy acceptors (long-wavelength emitting luminophores)35. It was almost unmanageable by adjusting the proportion of the luminophores to reduce the fluorescence quenching of the donors and sensitize the fluorescence enhancement of the acceptor. This is one of the challenges to generate white-light emission. Interestingly, the system reported in this research had little FRET phenomenon basically. The efficiency of FRET was very sensitive to the distance between the donor and the acceptor36. PVA not only formed hydrogen bonding but also enwrapped the luminophores when the water in the system evaporated, extending the space between two AuNC@histidine and poly-BrNpA. Moreover, the overlap between the absorption spectrum of poly-BrNpA and emission spectrum of AuNC@histidine was much less than 30% (in Figure 3c)37. So, with the addition of the AuNC component, the phosphorescent intensity of poly-BrNpA remained almost unchanged. Besides, a series of films based on multi-component systems have been prepared (Figure 3d). In 10
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particular, when the ratios of poly-BrNpA/AuNC@histidine was 1:1.68, the PL could be tuned for white-light emission. Its calculated CIE coordinates (0.33, 0.32) from the PL spectra was much closed to the pure white-light emission (0.33, 0.33), which was interesting and important for their potential applications in lighting devices and display media (Figure 3b).
Figure 3. a) The PL spectra of the dual-emission films of different proportions of poly-BrNpA (a’) and AuNC@histidine (b’) under λ=340 nm UV irradiation: The ratios of a’/b’= 0:11.76 (Ⅰ), 1:10.92 (Ⅱ), 1:10.08 (Ⅲ), 1:9.24 (Ⅳ), 1:8.4 (Ⅴ), 1:7.56(Ⅵ), 1:6.72(Ⅶ), 1:5.88 (Ⅷ), 1:5.06 (Ⅸ), 1:4.2 (Ⅹ), 1:3.36 (Ⅺ), 1:2.52 (ⅩⅡ), 1:1.68 (ⅩⅢ), 1:0.84 (ⅩⅣ), 1:0 (ⅩⅤ) (from above to below, in the ambient humidity:~70%-80%) b) Calculated CIE coordinates from the PL spectra of the PVA composite films shown in (a); c) Overlaps between the emission spectrum of donors and absorption spectrum of acceptors; d) The luminescence photos of dual-emission films of different proportions (under λ=365 nm UV irradiation), aqueous solutions on the quartz plates (above) and the according dried films (below), respectively.
PVA matrix in the triadic film. The hydrogen bond in polyacrylamide played more important 11
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role in suppressing the non-radiative relaxation and quenching of triplet state of some phosphors, which made them highly phosphorescent at ambient condition22. However, when the humidity is greater than 60%, the amorphous powder based on polyacrylamide would cause the collapse of the material, which was not good for the color switching (by drying/wetting). PVA matrix with abundant hydroxyl groups could effectively form hydrogen bonds with any water soluble materials (with AuNC@histidine and poly-BrNpA)38. Moreover, PVA was a good oxygen barrier39. These advantages make PVA a good matrix. This color switch could be stabilized in poly(vinyl alcohol) (PVA) matrix, and a more stable cycle could be carried out. The PVP and PAM matrix were also tested, whose properties of those films were not good (showed in Figure S6, S7).
Humidity response of the triadic film. To the best of our knowledge, the hydrogen bonds in poly-BrNpA chains could be broken by environmental humidity, while the fluorescence system (AuNC@histidine) could still generate stable and unchanged emission. Based on this nature of the two luminophor, a humidity responsive material combining the dual-emission of fluorescent Au nanoclusters and RTP copolymer were successfully prepared. In detail, a suitable proportion was selected from Table S1 (the ratio of poly-BrNpA/AuNC@histidine = 1:0.84), which was used to conduct the test for moisture response. As shown in Figure 4a, along with the increase of water volume, the RTP intensity gradually decreased to one fourth of the original level. But the intensity of fluorescence emission maintained. This phenomenon was distinct enough to be perceived by the naked eye when irradiated with 365 nm light (Figure 4d). The CIE coordinates also exactly demonstrated that the luminescence of this system changed from red (humidity = 10%) to white-light (humidity = 40%) and finally to green light (humidity = 90%) (Figure 4b, Table S2). Moreover, the core RTP unit of the poly-BrNpA-AuNC@histidine-PVAs could be increased or decreased, which could be repeated over many cycles, alternating between 10% and 90% (Figure 12
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4c).
Figure 4. a) The PL spectra changes under different humidity (from 10%-90%); b) Calculated CIE coordinates from the PL spectra changes under different humidity shown in (a); c) Reversibility of the humidity stimulated RTP spectrum of the ternary system. Changes in the RTP intensity at 590 nm along with changes in humidity. Humidity of 10% and 90% were alternated every 2h; d) The luminescence photos of dual-emission films in different humidity (under λ=365 nm UV irradiation).
Conclusions. In summary, a novel hybrid system poly-BrNpA-AuNC@histidine-PVA with adjustable
luminescence
was
constructed
via
combining
fluorescent
Au
nanocluster
AuNC@histidine with bluish green fluorescence and RTP polymer poly-BrNpA with orange room-temperature phosphorescence emission into PVA. When the ratios of poly-BrNpA with orange room-temperature phosphorescence emission and AuNC@histidine with bluish green fluorescence emission was 1:1.68, a white-light emission could be obtained with calculated CIE coordinates as (0.33, 0.32). In addition, we had demonstrated a novel strategy to create a humidity responsive hybrid material and its functional film devices, due to the specific responses of phosphorescent and 13
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fluorescent materials to the change of microenvironment. Their humidity responsiveness was thoroughly investigated. Employing such humidity-responsive properties, this material could be potentially used in the field of anti-counterfeiting and biological imaging by time resolved techniques in future. Supporting Information Preparation routine of poly-BrNpA, 1H and
13
C NMR of the intermediates, the TEM spectra of
AuNC@histidine, the different mole proportions of triadic system and calculated CIE coordinates, calculated CIE coordinates from the PL spectra changes under different humidity, the excitation spectrum of poly-BrNpA, the absorption spectrum of poly-BrNpA/AuNC@histidine in different humidity, hydrogen bonding between components, the luminescence photos of dual-emission films of different proportions and conditions, the luminescence photos of dual-emission PAM films of different proportions, the luminescence photos of dual-emission PVP films. These material are available free of charge via the Internet at http://pubs.acs.org. AUTHOR INFORMATION
Corresponding Author *E-mail: X. M., maxiang@ecust.edu.cn & tianhe@ecust.edu.cn
Notes The authors declare no competing financial interest. ACKNOWLEDGMENT We gratefully acknowledge financial support the financial support from NSFC/China (21788102, 21722603, 21421004 and 21476075), Programme of Introducing Talents of Discipline to 14
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Universities (B16017), the Innovation Program of Shanghai Municipal Education Commission and the Fundamental Research Funds for the Central Universities (222201717003). REFERENCES
(1) Hostetler, M. J.; Wingate, J. E.; Zhong, C. J.; Harris, J. E.; Vachet, R. W.; Clark, M. R.; Londono, J. D.; Green, S. J.; Stokes, J. J.; Wignall, G. D.; Glish, G. L.; Porter, M. D.; Evans, N. D.; Murray, R. W. Alkanethiolate Gold Cluster Molecules with Core Diameters from 1.5 to 5.2 nm: Core and Monolayer Properties as a Function of Core Size. Langmuir, 1998, 14, 17-30. (2) Kelly, K. L.; Coronado, E.; Zhao, L. L.; Schatz, G. C. The Optical Properties of Metal Nanoparticles: The Influence of Size, Shape, and Dielectric Environment. J. Phys. Chem. B 2003, 107, 668-677. (3) Templeton, A. C.; Wuelfing, W. P.; Murray, R. W. Monolayer-Protected Cluster Molecules. Acc. Chem. Res. 2000, 33, 27-36. (4) Agasti, S. S.; You, C.-C.; Arumugam, P.; Rotello, V. M. Structural Control of the Monolayer Stability of Water-Soluble Gold Nanoparticles, J. Mater. Chem. 2008, 18, 70-73. (5) Akamatsu, K.; Deki, S. Characterization and Optical Properties of Gold Nanoparticles dispersed in Nylon 11 Thin Films, J. Mater. Chem. 1997, 7, 1773-1777. (6) Zheng, J.; Nicovich, P. R.; Dickson, R. M. Highly Fluorescent Noble-Metal Quantum Dots, Annu. Rev. Phys. Chem. 2007, 58, 409-431. (7) Cui, M.;
Zhao, Y.; Song, Q. Synthesis, Optical Properties and Applications of
Ultra-Small Luminescent Gold nanoclusters, Trac-Trend. Anal. Chem. 2014, 57, 73-82.
15
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(8) Han,
S.;
Zhang,
Z.;
Li,
S.;
Qi,
L.;
Xu,
G.
Page 16 of 21
Chemiluminescence
and
Electrochemiluminescence Applications of Metal Nanoclusters, Sci. China Chem. 2016, 59, 794-801. (9) Wu, W. H.; Sun, J. F.; Cui, X. N.; Zhao, J. Z. Observation of the Room Temperature Phosphorescence of Bodipy in Visible Light-harvesting Ru(II) Polyimine Complexes and
Application
as
Triplet
Photosensitizers
for
Triplet–Triplet-Annihilation
Upconversion and Photocatalytic Oxidation, J. Mater. Chem. C, 2013, 1, 4577-4589. (10) Yang, X. G.; Yan, D. P. Strongly Enhanced Long-Lived Persistent Room Temperature Phosphorescence Based on the Formation of Metal-Organic Hybrids, Adv. Opt. Mater. 2016, 4, 897-905. (11) Bolton, O.; Lee, K.; Kim, H.-J.; Lin, K. Y.; Kim, J. Activating Efficient Phosphorescence from Purely Organic Materials by Crystal Design, Nat. Chem. 2011, 3, 205-210. (12) Gong, Y.; Zhao, L.; Peng, Q.; Fan, D.; Yuan, W. Z.; Zhang, Y.; Tang, B. Z. Crystallization-Induced Dual Emission from Metal- and Heavy Atom-Free Aromatic Acids and Esters, Chem. Sci. 2015, 6, 4438-4444 (13) Gong, Y.; Chen, G.; Peng, Q.; Yuan, W. Z.; Xie, Y.; Li, S.; Zhang, Y.; Tang, B. Z. Achieving
Persistent
Room
Temperature
Phosphorescence
and
Remarkable
Mechanochromism from Pure Organic Luminogens, Adv. Mater. 2015, 27, 6195-6201. (14) Liu, Y.; Zhan, G.; Liu, Z.W.; Bian, Z. Q.; Huang, C. H. Room-Temperature Phosphorescence from Purely Organic Materials, Chin. Chem. Lett. 2016, 27, 1231-1240. (15) Yang, X. G. Yan, D. P. Long-Afterglow Metal-Organic Frameworks: Reversible Guest-Induced Phosphorescence Tunability. Chem. Sci. 2016, 7, 4519-4526. 16
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(16) Lee, D.; Bolton, O.; Kim, B. C.; Youk, J. H.; Takayama, S.; Kim, J. Room Temperature Phosphorescence of Metal-Free Organic Materials in Amorphous Polymer Matrices, J. Am. Chem. Soc. 2013, 135, 6325-6329. (17) Kwon, M. S.; Lee, D.; Seo, S.; Jung, J.; Kim, J. Tailoring Intermolecular Interactions for Efficient Room-Temperature Phosphorescence from Purely Organic Materials in Amorphous Polymer Matrices, Angew. Chem. Int. Ed. 2014, 53, 11177-11181. (18) Jin, P.; Guo, Z.; Chu, J.; Tan, J.; Zhang, S.; Zhu, W. Screen-Printed Red Luminscence Copolymer
Film
Containing
Cyclometalated
Iridium(III)
Complex
as
a
High-Permeability Dissolved-Oxygen Sensor for Fermentation Bioprocess. Ind. Eng. Chem. Res. 2013, 52, 3980-3987. (19) Guo, R.; Yan, D. P. Ordered Assembly of Hybrid Room-Temperature Phosphorescence Thin Films Showing Polarized Emission and The Sensing of VOCs. Chem. Commun. 2017, 39, 5408-5411. (20) Hirata, S.; Totani, K.; Zhang, J.; Yamashita, T.; Kaji, H.; Marder, S. R.; Watanabe, T.; Adachi, C. Efficient Persistent Room Temperature Phosphorescence in Organic Amorphous Materials under Ambient Conditions, Adv. Funct. Mater. 2013, 23, 3386-3397 (21) Katsurada, Y.; Hirata, S.; Totani, K.; Watanabe, T.; Vacha, M. Photoreversible On–Off Recording of Persistent Room-Temperature Phosphorescence, Adv. Opt. Mater. 2015, 3, 1726-1737. (22) Chen, H.; Yao, X. Y.; Ma, X.; Tian, H. Amorphous, Efficient, Room-Temperature Phosphorescent Metal-Free Polymers and Their Applications as Encryption Ink, Adv. Opt. Mater. 2016, 4, 1397-1401.
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(23) Ma, X; Cao, J.; Wang, Q.; Tian, H. Photocontrolled Reversible Room Temperature Phosphorescence (RTP) Encoding β-Cyclodextrin Pseudorotaxane, Chem. Commun. 2011, 47, 3559-3561. (24) Chen, H.; Xu, L.; Ma, X.; Tian, H. Room Temperature Phosphorescence of 4-Bromo-1,8-Naphthalic Anhydride Derivative-Based Polyacrylamide Copolymer with Photo-Stimulated Responsiveness, Polym. Chem. 2016, 7, 3989-3992. (25) Gong, Y.; Chen, H.; Ma, X.; Tian, H. A Cucurbit[7]uril Based Molecular Shuttle Encoded by Visible Room-Temperature Phosphorescence, ChemPhysChem 2016, 17, 1934-1938. (26) Guo, R.; Yan, D. P. Layered Host-Guest Long-Afterglow Ultrathin Nanosheets: High-Efficiency Phosphorescence Energy Transfer at 2D Confined Interface. Chem. Sci. 2017, 8, 590-599. (27) Wang, H.; Wang, H.; Yang, X.; Wang, Q.; Yang, Y. Ion-Unquenchable and Thermally “On–Off” Reversible Room Temperature Phosphorescence of 3-Bromoquinoline Induced by Supramolecular Gels, Langmuir 2015, 31, 486-491 (28) Chen, H.; Ma, X.; Wu, S.; Tian, H. A Rapidly Self-Healing Supramolecular Polymer Hydrogel with Photostimulated Room-Temperature Phosphorescence Responsiveness, Angew. Chem. Int. Ed. 2014, 53, 14149-14152. (29) Maiti, D. K.; Roy, S.; Baral, A.; Banerjee, A. A Fluorescent Gold-Cluster Containing a New Three-Component System for White Light Emission Through a Cascade of Energy Transfer, J. Mater. Chem. C 2014, 2, 6574-6581. (30) Kwon, M. S.; Yu, Y.; Cobur, C.; Phillips, A. W.; Chung, K.; Shanker, A.; Jung, J.; Kim, G.; Pipe, K.; Forrest, S. R.; Youk, J. H.; Gierschner, J.; Kim, J. Suppressing Molecular
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Motions for Enhanced Room-Temperature Phosphorescence of Metal-Free Organic Materials, Nat. Commun. 2015, 6, 8947-8956. (31) Guo, P.; Chen, Q.; Liu T.; Xu, L.; Yang, Q.; Qian, X. Development of Unsymmetrical Dyads
As
Potent
Noncarbohydrate-Based
Inhibitors
against
Human
β-N-Acetyl-d-hexosaminidase, ACS Med. Chem. Lett. 2013, 4, 527-531. (32) Xi, Y.; Shi, M. M.; Zhou, R. J.; Chen, X. Q.; Chen, H. Z. Blending of HAuCl4 and Histidine in Aqueous Solution: a Simple Approach to the Au10 Cluster, Nanoscale 2011, 3, 2596-2601. (33) Zhou, R. J.; Shi, M. M.; Chen, X. Q.; Wang, M.; Chen, H. Z. Atomically Monodispersed
and
Fluorescent
Sub-Nanometer
Gold
Clusters
Created
by
Biomolecule-Assisted Etching of Nanometer-Sized Gold Particles and Rods, Chem. Eur. J. 2009, 15, 4944-4951. (34) Jin, R. Quantum sized, thiolate-protected gold nanoclusters, Nanoscale 2010, 2, 343-362. (35) Sanjoy, M.; Pakkirisamy, T. Organic White-Light Emitting Materials, Dyes Pigments 2014, 110, 2-27. (36) Chen, G.; Song, F.; Xiong, X.; Peng, X.
Fluorescent Nanosensors
Based
on Fluorescence Resonance Energy Transfer (FRET), Ind. Eng. Chem. Res. 2013, 52, 11228–11245. (37) Bryce, T. B.; Emily, S. W.; Zhang, S.; Michael Z. L.; Chu, J. A Guide to Fluorescent Protein FRET Pairs, Sensors 2016, 16, 1488-1511. (38) Hameed A. A.; Andrew P. M. Room-Temperature Phosphorescence from Films of Isolated Water-Soluble Conjugated Polymers in Hydrogen-Bonded Matrices, Adv. Funct. Mater. 2012, 22, 3824-3832. 19
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(39) Julien, G.; Pascal, W. W. C.; Agnès R.; Sandrine, T.; Jean, L. G. Photochemical Behavior of PVA as an Oxygen-Barrier Polymer for Solar Cell Encapsulation. RSC Adv. 2011, 1, 1471-1481.
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A novel triadic system poly-BrNpA-AuNC@histidine-PVA via histidine modified Au nanocluster embedded into a poly(vinyl alcohol) (PVA) matrix with bluish green fluorescence and 4-bromo-1,8-naphthalicanhydride
derivative
polymer
with
orange
a
room-temperature
phosphorescence coordinated in the matrix, were designed and prepared, which provided a new strategy in developing fluorescence-phosphorescence hybrid system with tunable multicolor emission property by humidity change.
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