Highly Emissive and Color-tunable Perovskite Crosslinkers for

Applications of Polymer, Composite, and Coating Materials

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Highly Emissive and Color-tunable Perovskite Crosslinkers for Luminescent Polymer Networks Yumeng Xin, Wei Shen, Zhengtao Deng, and Jiuyang Zhang ACS Appl. Mater. Interfaces, Just Accepted Manuscript • DOI: 10.1021/acsami.8b08054 • Publication Date (Web): 02 Aug 2018 Downloaded from http://pubs.acs.org on August 2, 2018

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ACS Applied Materials & Interfaces

Highly Emissive and Color-tunable Perovskite Crosslinkers for Luminescent Polymer Networks Yumeng Xin1, Wei Shen,2 Zhengtao Deng,2 Jiuyang Zhang1* 1

School of Chemistry and Chemical Engineering, Southeast University, Nanjing,

211189, PR China; Jiangsu Hi-Tech Key Laboratory for Biomedical Research, 211189, Nanjing, PR China 2

Department of Biomedical Engineering, College of Engineering and Applied

Sciences, Nanjing National Laboratory of Microstructures, Nanjing University, Nanjing, Jiangsu 210093, PR China KEYWORDS: Perovskites, Tunable emission, Luminescent, Crosslinkers, Network ABSTRACT: Emissive crosslinkers are of special interest for polymer science due to their

ability

to

endow

polymer

networks

with

luminescent

properties.

Methylammonium lead halide perovskite nanoparticles (MAPbClxBr3-x NPs) are extensively explored for optical and optoelectronic applications. In this work, MAPbClxBr3-x NPs with crosslinkable and polymerizable ligands are successfully prepared as new emissive crosslinkers for polymer networks. Commercially available reagent, 2-aminoethyl methacrylate hydrochloride (AMHCl), can act as ligands to stabilize MAPbBr3 NPs in solution. Compared with traditional ligands (oleic acid (OA) and oleylamine (OAm)), AMHCl retains the architecture of perovskite effectively and afford the polymerizable groups (vinyl) on the surface of perovskites. The as-prepared MAPbClxBr3-x NPs can be served as crosslinkers in the radical

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polymerization of (meth)acrylates by UV-light to form polymer networks. Meanwhile, such crosslinkable emitters exhibit bright luminescence and color-tunability at room temperature, attributed by unique halide exchange of perovskites between CH3NH3Br and AMHCl, which provides the polymer networks with varied emissive bands. These perovskite-crosslinked networks showed high air stability, water stability and prominent photoluminescence quantum yields (PLQYs). Based on these excellent properties, white light emitting diodes (LEDs) were successfully fabricated from these perovskite-crosslinked composites with color coordinate values at (0.316, 0.315), very close to the standard coordinates of white light. This work elucidates a new and convenient technique to convert nanocrystals into luminescent crosslinkers to build functional polymeric networks for technological applications. ■ INTRODUCTION

Luminescent polymer networks have received lots of interest due to the combination of flexible polymers and luminescence for various applications, including displays, coating and bioimaging materials.1-3 In fabrication of luminescent polymer networks, the most challenging issue is the difficulty in control over the dispersion of luminescent units in the network, which usually leads to aggregation and poor luminescent behaviors, especially for those with inorganic emitters (for example: lanthanide salts).4 The modification of monomers5-7 or crosslinkers8-9 with luminescent groups can avoid the inhomogeneity among the networks and luminescent molecules, while this method requires tedious synthesis and typically applies for organic emitters. Only a few modified inorganic emitters have been reported to be covalently attached with polymer networks, such as CdSe quantum dots.10-11 With the ability of crosslinking, the applications of CdSe quantum dots have


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been broadly extended to biomedicine, luminescent elastomers and optical devices.12-13 To meet the increasing technological demands, finding new compatible inorganic emitters by convenient methods is very urgent in polymer science. Among various emitters, hybrid organic-inorganic lead halide perovskites have attracted great attention due to their excellent performance including tunable emission spanning the whole visible range, narrow-band emission as well as high photoluminescence quantum yields (PLQYs).14-18 However, the stability and degradation of perovskites severely limited their advanced applications.19 To improve the performance of the perovskites, the surface engineering of perovskites has been intensively explored.20-27 Liu and his coworkers reported that besides oleic acid (OA) and oleylamine (OAm), short ammonium ligands could also protect perovskite nanocrystals to induce various morphologies. This special ammonium salt can replace the traditional oleic acid and oleylamine which may lead to poor carrier injection and transportation of perovskites.28 Soranyel et al.29 in 2016 showed the water-resistant MAPbBr3

perovskite

nanoparticles

with

high

PLQYs

by

using

2-adamantylammonium bromide as the capping ligand on the nanocrystal surface. These studies strongly indicated the possibility of functional ammonium salts from surface engineering to create luminescent crosslinkers of perovskites.



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Scheme 1. Schematic illustration of the surface engineering of perovskite crystals and the formation of crosslinked networks. a) Precursor solution (PbBr2, MABr and AMHCl with different molar ratios dissolved in DMF solution). b) The formation of MAPbClxBr3-x crosslinkers with AMHCl as capping ligand. c) The formation of polymer networks with functionalized MAPbClxBr3-x NPs as crosslinkers under UV-light.

In this work, new luminescent crosslinkers were successfully created by surface engineering of MAPbClxBr3-x NPs with crosslinkable and polymerizable methacrylic ammonium

ligands

(2-aminoethyl

methacrylate

hydrochloride

(AMHCl),

commercially available salts). AMHCl can not only enhance the stability of perovskite NPs in solution, but also afford the polymerizable groups on the surface of perovskites (Scheme 1). The resulted MAPbClxBr3-x NPs can be served as the crosslinkers in the radical polymerization of (meth)acrylates by 365 nm UV-light with the

photoinitiators

(diphenyl(2,4,6-trimethylbenzoyl)phosphine

oxide

(TPO)).

Specially, these as-prepared emissive crosslinkers exhibited high luminescence and color-tunability due to the desirable characteristics of narrow-band emission and unique halide exchange in perovskites. These functionalized emitters are successfully applied as crosslinkers for (meth)acrylates to fabricate colorful networks with high air


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stability, water stability and prominent quantum yields (as high as 65.9%). Based on these excellent properties, we further explore the application of these crosslinked networks in white light emitting diodes (LEDs) with color coordinate values at (0.316, 0.315) and color temperate at 6436.32 K, very close to the standard coordinates of white light. This work provides a new and convenient technique to convert perovskite nanocrystals into luminescent crosslinkers to build functional polymeric networks for technological applications, such as wide-color gamut display devices and liquid crystal display (LCD) backlight utilization.

■ RESULT AND DISCUSSION Precursor solution were prepared by mixing 2-aminoethyl methacrylate hydrochloride, methylammonium bromide and lead bromide in DMF with molar ratio of CH3NH3Br : AMHCl : PbBr2 at 1.22:0.80:1. The AMHCl attached perovskites were prepared by dropping the precursor solutions (50 µL) into a vigorously stirred toluene or bulk monomer solution (1 mL). Strong blue-green emission (Figure 1a1 and 1a2) emerged immediately after the injection under the UV illumination (365 nm). This phenomenon indicated that the MAPbCl0.60Br2.40 NPs have been successfully formed in solution by using AMHCl as capping ligands which can help to control the size of nanocrystals and disperse them in non-selective solvent (such as toluene and bulk monomer) through the surface functionalization. One controlled trial by forming the MAPbBr3 perovskite NPs without ligands in bulk butyl methacrylate (BMA) solution, the solution is turbid and yellow (Figure S1) indicated that the nanoparticles were aggregated without ligands. This control experimental confirmed that the AMHCl not only provided the polymerizable ligands on surface of perovskite NCs, but also enhanced the stability of emissive perovskites in BMA solution, which was critically



important for the following in situ polymerization.

Figure 1. a) Photos of MAPbCl0.60Br2.40 crosslinkers obtained from bulk BMA solution under ambient room light (left) and UV illumination (right). b) Fourier transform infrared (FTIR) spectra of MAPbCl0.60Br2.40 crosslinkers, AMHCl and MABr. c) Transmission electron microscopy (TEM) image of MAPbCl0.60Br2.40 crosslinkers obtained from bulk BMA solution. d) X-ray diffraction (XRD) patterns of MAPbCl0.60Br2.40 crosslinkers obtained from bulk BMA solution. MAPbBr3 crystals were obtained with oleylamine and oleic acid as ligands from toluene. Fourier transform infrared (FTIR) spectroscopy was used to demonstrate the attachment of AMHCl on the surface of MAPbCl0.60Br2.40 crosslinkers (Figure 1b). Crosslinker powders were washed by butanol several times to ensure the removal of residual AMHCl ligands before FTIR. MAPbCl0.60Br2.40 crosslinkers with AMHCl 6 ACS Paragon Plus Environment

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ligands exhibit characteristic absorptions at 1722 cm−1, 1295 cm−1 and 1166 cm−1, that are attributed to the C=O, C-O and C-N stretching and bending vibration of AMHCl ligands, respectively. Figure 1c shows a transmission electron microscopy (TEM) image of MAPbCl0.60Br2.40 crosslinkers obtained from emissive bulk BMA solution, similar as the typical MAPbBr3 NPs obtained in toluene by using oleic acid and oleylamine.30 The MAPbCl0.60Br2.40 crosslinkers have an average diameter of 4.7 nm with a well size distribution and show the excellent dispersion of crosslinkers in bulk monomer solution. The X-ray diffraction (XRD) patterns of MAPbCl0.60Br2.40 crosslinkers (Figure 1d) obtained from bulk BMA solution show that the nanoparticles have a well-defined three-dimensional structure. The featured peaks at 15.10o, 21.40o, 30.42o, 34.12o, 43.52o and 46.32o are assigned to the {100}, {110}, {200}, {210}, {220} and {300} lattice planes of a MAPbX3 structure (Table S5), respectively, indicating the cubic crystals, similar as previous reports.30 X-ray photoelectron spectroscopy (XPS) (Figure S6, S7, S8 and S9) showed peaks at 138.1 eV and 142.9 eV (Pb 4f), 401.6 eV (N 1s), 67.9 eV (Br 3d) and 197.6 eV (Cl 2p) of MAPbCl0.60Br2.40 crosslinkers clearly indicated the existence of Pb, N, Br and Cl elements, respectively.30 And the atomic ratios of Br and Cl for the MAPbClxBr3-x crosslinker powders obtained from BMA solution were measured by XPS measurement (Table S2) according to the method in previous report.46 The content of Cl ion in the MAPbClxBr3-x crosslinker NPs is slightly different than the reported Cl/Br atomic ratio was calculated based on the stoichiometry of the MAPbClxBr3-x in BMA solution (Table S1).



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Figure 2. Photos of color-tunable MAPbClxBr3-x crosslinkers formed in bulk BMA solution under a) ambient room light and b) UV illumination. c) Normalized PL spectra of MAPbClxBr3-x crosslinkers formed in bulk BMA solution. d) Normalized absorption spectra of MAPbClxBr3-x crosslinkers formed in bulk BMA solution. (a1/b1: MAPbCl0.83Br2.17;

a2/b2:

MAPbCl0.72Br2.28;

a3/b3:

MAPbCl0.60Br2.40;

a4/b4:

MAPbCl0.48Br2.52; a5/b5: MAPbCl0.36Br2.64) Interestingly, the emissive wavelength of the prepared perovskite-crosslinkers could be conveniently tuned via controlling the feeding ratio of CH3NH3Br and the ligand AMHCl. Due to the unique halide exchange in perovskite,30-35 the absorption 8 ACS Paragon Plus Environment

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and photoluminescence wavelength can be finely tuned from 407 nm to 515 nm by varying the molar ratios of anions (Br and Cl). The preparation of MAPbClxBr3-x crosslinkers with different emissive bands was addressed using a 1:2 molar ratio between the lead bromide (PbBr2) and ammonium salts (CH3NH3Br/AMHCl molar ratio is shown in Table S1). Strongly different color-emission (Figure 2a and 2b) was observed immediately under the UV illumination (365 nm) after the injection of precursor solution. As shown in Figure 2c and 2d, the normalized photoluminescence (PL) spectra and absorption spectra of MAPbClxBr3-x crosslinkers formed in bulk monomer solution demonstrated the successful fabrication of brightly luminescent and color-tunable MAPbClxBr3-x crosslinkers (from 451 nm to 515 nm) at room temperature by fine-tuning the molar ratio between CH3NH3Br and AMHCl. The normalized PL spectra of these bulk BMA solutions have a very narrow full width at half-maximum (FWHM) ranging from 22 to 26 nm (more details were shown in Table S3). Other Cl-substituted MAPbClxBr3-x crosslinkers obtained from bulk BMA solution have a similar size to MAPbCl0.60Br2.40 (Figure S3). The ligand concentration would not affect the size of the resulted emitters.21 On the other hand, other Cl-substituted MAPbClxBr3-x crosslinkers have similar XRD patterns to MAPbCl0.60Br2.40 crosslinkers (Figure S2). As the amount of chloride increases in perovskite nanoparticles, the 2θ angle signals value of XRD patterns slightly increased (Figure S2 and Table S5), which is attributed to the lattice expansion by substitution of smaller Cl ions, indicating that halides ions redistributed congeneric throughout the NPs as reported by other works.36



Figure

3.

Photos

of

transparent

disks

Page 10 of 24

(diameter:

3

cm)

from

MAPbClxBr3-x-crosslinked PBMA networks under a) ambient room light and b) UV illumination. c)

Normalized PL spectra of MAPbClxBr3-x-crosslinked PBMA

networks. d) Cross-sectional scanning electron microscope (SEM) image of MAPbCl0.60Br2.40-crosslinked PBMA networks. (a1/b1: MAPbCl0.83Br2.17; a2/b2: MAPbCl0.72Br2.28;

a3/b3:

MAPbCl0.60Br2.40;

a4/b4:

MAPbCl0.48Br2.52;

a5/b5:

MAPbCl0.36Br2.64) With the as-prepared MAPbClxBr3-x crosslinkers, poly(butyl methacrylate) (PBMA) networks can effectively be fabricated via the in situ radical polymerization. After obtaining the MAPbClxBr3-x crosslinkers in bulk BMA solution, TPO was irradiated by UV-light (365nm) to initiate the polymerization. After exposure under 10 ACS Paragon Plus Environment

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UV-light for 12 h, rigid solid and transparent PBMA networks with brightly luminescent and different colors were finally obtained (Figure 3a and 3b). The MAPbClxBr3-x crosslinkers could be also applied for networks of methyl methacrylate (MMA) (Figure S11) and butylacrylate (BA) (Figure S12). However, for styrene, only viscous liquid formed with no gelation during the photo polymerization due to the low polymerization rate to afford polymer networks.37-38 We also used the MAPbCl0.60Br2.40 crosslinker powder to fabricate the MAPbCl0.72Br2.28-crosslinked PBMA network. Comparing with the MAPbCl0.72Br2.28-crosslinked PBMA network fabricated by in situ polymerization, the MAPbCl0.72Br2.28-crosslinked PBMA network fabricated by using crosslinker powder have lower PLQYs (36.7%) (Figure S10 and Table S6). This was due to the tedious separation and preparation of perovskite, which may lead to aggregation and poor luminescent behaviors. The in situ formed polymer networks can also effectively overcome the issue of aggregation of inorganic crystals and retain the emissive features of MAPbClxBr3-x emitters. MAPbClxBr3-x crosslinkers are covalently attached and well dispersed in the crosslinked PBMA networks without large aggregation as indicated by cross-sectional SEM images (Figure 3d) and transmission electron microscopy (TEM) image (Figure S4). The MAPbCl0.60Br2.40 crosslinkers have an average diameter of 4.7 nm with a well size distribution and show the excellent dispersion of crosslinkers in PBMA networks, similar to the MAPbCl0.60Br2.40 crosslinkers obtained in bulk BMA solution. MAPbClxBr3-x-crosslinked PBMA networks with varied colors have the similar PL emission peaks with narrow FWHM to the corresponding MAPbClxBr3-x crosslinkers formed in bulk BMA solutions (more details were shown in Table S4). Importantly, high PL quantum yields (PLQYs) of MAPbClxBr3-x-crosslinked PBMA networks

were

observed,

reaching

as


excellent

as

65.9%


(MAPbCl0.72Br2.28-crosslinked PBMA networks), better than it (47.3%) of MAPbCl0.72Br2.28-PBMA composite with oleic acid (OA) and oleylamine (OAm) as capping ligands (Figure S16 and Table S10), indicating the enhanced performance when using AMHCl as capping ligands. Furthermore, comparing to the semitransparent MAPbCl0.72Br2.28-PBMA composite (OA and OAm as capping ligands), the MAPbCl0.60Br2.40-PBMA network from AMHCl ligands is transparent (Figure S16). This was possibly attributed by the faster crosslinking of monomers by AMHCl surface ligands on perovskites to avoid aggregation of MAPbClxBr3-x in the materials, which improved stability of perovskites during the polymerization.

Figure 4. a) Time-resolved PL decays and fitting curves of emissive bulk BMA solution and MAPbCl0.72Br2.28-crosslinked PBMA networks. b) Time-dependent PL intensity of the MAPbClxBr3-x-crosslinked PBMA networks in air. c) Normalized PL spectra of MAPbCl0.72Br2.28-crosslinked PBMA networks before and after immersing 12 ACS Paragon Plus Environment

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in water for 30 days. d) Photos of the MAPbClxBr3-x-crosslinked PBMA networks in water taken under UV-illumination. Air stability, water resistance and life time are crucial properties of methylammonium lead halide perovskite for their applications in light emitters for light-emitting diodes (LEDs).39-44 Our results indicated that covalent attaching of perovskites with polymer networks could largely improve the luminescent performance of the perovskites. The average photoluminescence (PL) time (τ1, τ2) of MAPbCl0.72Br2.28 crosslinkers formed in bulk butyl methacrylate (BMA) solution before and after polymerization were measured (Figure 4a and Table S7) by time-resolved PL spectra. τ1 is attributed to the intrinsic recombination while τ2 comes from surface state recombination. PL life time ((3.9 ns, 27.4 ns) and (4.3 ns, 37.5 ns)) were found for emissive bulk BMA solution and MAPbCl0.72Br2.28-crosslinked PBMA networks, respectively, showing the improved life time after crosslinking. The MAPbClxBr3-x-crosslinked PBMA networks in this work exhibit remarkable stability in air atmosphere and excellent water resistance. Figure 4b showed that the PL intensity of the MAPbCl0.72Br2.28-crosslinked poly(butyl methacrylate) (PBMA) networks could remain as high as 91% in air, for 30 days, and other MAPbClxBr3-x-crosslinked PBMA networks also exhibited the excellent stability in air atmosphere (Figure 4b and Table S8). PBMA with outstanding hydrophobic character protects the structure of MAPbClxBr3-x crosslinkers and retain the size, crystallinity and optical properties of MAPbClxBr3-x crosslinkers. Furthermore, immersing MAPbClxBr3-x-crosslinked PBMA networks in water, the PL intensity of MAPbCl0.72Br2.28-crosslinked PBMA networks could remain 72% for 60 hours (more details in Figure S13 and Table S9). Moreover, after immersing in water for one month, no change in peak shape of PL spectra (Figure 4c) was observed, exhibiting 13 ACS Paragon Plus Environment


the

high

stability

in

moisture

atmosphere.

Page 14 of 24

Figure

4d

showed

MAPbClxBr3-x-crosslinked PBMA networks are still strongly emissive after immersing in water for one month. The different polymer-water affinity determined the behaviors of water resistance.45 The polymer (polybutyly methacrylate) (PBMA) utilized in our work was similar to poly(methyl methacrylate) (PMMA). The water resistance of MAPbClxBr3-x-crosslinked PBMA networks in our work are poorer than MAPbBr3-polymer (polystyrene and polyvinyl chloride) composites. But our system showed better water-resistance than MAPbBr3-PMMA materials in the previous study due to the crosslinked network to possibly decrease water permeability.

Figure 5. a) Schematic illustration of the configuration of the prototype LED device (The LED device contains three parts: the KSF/adhesive composite was fabricated by blending red emissive rare-earth phosphor K2SiF6:Mn4+ (KSF) powder with UV-cured adhesive and curing under UV light for 1 h; MAPbCl0.36Br2.64-crosslinked PBMA networks film was placed between KSF/adhesive composite and blue LED; the blued LED serve as luminous source at the bottom of the LED device). b) Photos of 14 ACS Paragon Plus Environment

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MAPbCl0.36Br2.64-crosslinked PBMA networks film (1) and KSF composite film (2) and white LED (3) under UV-illumination. c) Emission spectrum of the constructed white LED. d) The color coordinates (gray dot) of obtained white LED in CIE diagram. The available brightly luminescent and color-tunable MAPbClxBr3-x-crosslinked PBMA networks with high PLQYs provide the opportunities to explore their application

in

emitters

for

prototype

LED

device.

We

choose

MAPbCl0.36Br2.64-crosslinked PBMA networks (Figure 5b1) with green emissive (PL emission peak at 521 nm) to demonstrate the property for white LED device. As shown

in Figure

5a, white

LED device

were fabricated

by combing

MAPbCl0.36Br2.64-crosslinked PBMA networks and red emissive rare-earth phosphor K2SiF6:Mn4+ (KSF) (with narrow FWHM in the range of 20 nm) composite as the color converters with a blue commercial blue LED (454 nm). The red emissive KSF composite (Figure 5b2) was fabricated by curving the mixture of KSF powder and UV-cured adhesive on the surface of quartz plate under UV-light (365 nm) for an hour. Figure 5b3 showed the successful fabrication of the WLED by the prepared MAPbCl0.36Br2.64-crosslinked PBMA networks and KSF composite, which was confirmed by the corresponding electroluminescence (EL) spectrum in Figure 5c. As shown in the CIE diagram of Figure 5d and Figure S14, the color coordinate value of obtained white LED is (0.316, 0.315) which approximate the standard coordinates of white light. The color temperature (CCT) of the white LED was achieved at 6436.32 K. The MAPbCl0.36Br2.64-crosslinked PBMA networks with narrow FWHM and high PLQYs in this work showing purer green color which are vital for the potential application in the field of wide-color gamut display devices and provide the possibility for liquid crystal display (LCD) backlight utilization. Moreover, different 15 ACS Paragon Plus Environment


Page 16 of 24

LEDs with varied colors were prepared by the same fabricating method of the white LED device (Figure S15). Green, blue and purple color LEDs were obtained by using different MAPbClxBr3-x-crosslinked PBMA networks. These results imply the potential of organic perovskite quantum dots (IPQDs) in broad lighting and display devices.

■ CONCLUSION

In summary, new emissive crosslinkers from MAPbClxBr3-x NPs was successfully and conveniently prepared to fabricate polymer networks. Commercially available reagent, 2-aminoethyl methacrylate hydrochloride (AMHCl), not only can be served as ligands to stabilize MAPbBr3 NPs in solution, but also afford the polymerizable groups (vinyl) on the surface of perovskites. The as-prepared MAPbClxBr3-x NPs act as crosslinkers in the radical polymerization of (meth)acrylates to fabricate various polymer networks. Such perovskite crosslinkers exhibit bright luminescence and color-tunability at room temperature, owing to unique halide exchange of MAPbClxBr3-x NPs by adjusting the molar ratios of CH3NH3Br and AMHCl, which finally provides the polymer networks with controllable emissive bands. Compared with the MAPbBr3-PBMA physical blending composite with oleic acid (OA) and oleylamine (OAm) as capping ligands, covalently crosslinked MAPbClxBr3-x-crosslinked polymer networks showed higher air stability, PLQYs, and better water resistance. With all these significant enhancement,

white

LED

was

fabricated

with

the

green

emissive

MAPbCl0.36Br2.64-crosslinked PBMA networks with color coordinate values at (0.316, 0.315) and color temperature at 6436.32 K. We believe this novel and convenient technique to convert perovskite nanocrystals into luminescent crosslinkers depicts


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new route to apply inorganic emitters into functional polymeric networks for advanced applications.

■ ASSOCIATED CONTENT

Supporting Information The Supporting Information is available free of charge on the ACS Publications website at DOI: Photos of MAPbBr3 and MAPbCl0.60Br2.40 crosslinkers in bulk BMA solution; precursor solution with different molar ratio of AMHCl, MABr and PbBr2; details of MAPbClxBr3-x crosslinkers; details of MAPbClxBr3-x-crosslinked PBMA networks; XRD patterns of MAPbClxBr3-x crosslinkers; signals of XRD patterns of MAPbClxBr3-x crosslinkers; signals of FTIR spectra; TEM images of MAPbClxBr3-x

crosslinkers;

normalized

absorption

spectra

of

MAPbClxBr3-x-crosslinked PBMA networks; XPS patterns of MAPbCl0.60Br2.40 crosslinkers; photos of MAPbCl0.60Br2.40-crosslinked PMMA networks; photos of MAPbCl0.60Br2.40-crosslinked PBA networks; photo of viscous liquid PBA without MAPbCl0.60Br2.40 crosslinkers; time-dependent PL intensity of MAPbClxBr3-x-crosslinked PBMA networks in water; CIE diagram of white LED; photos of MAPbBr3 in bulk BMA solution and PBMA composite; details of MAPbBr3-PBMA composite; normalized PL and absorption spectra of MAPbBr3-PBMA composite.

■AUTHOR INFORMATION

Corresponding Authors *E-mail: [email protected] 17 ACS Paragon Plus Environment


Notes The authors declare no competing financial interest.

■ACKNOWLEDGEMENTS

Funding for this work was provided by the National Natural Science Foundation of China (Grant No. 21504013, 21774020 and 51502130).

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Highly Emissive and Color-tunable Perovskite Crosslinkers for

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