Stable and Bright CsPbX₃ Nanocrystals in Metal–Organic Frameworks for White Light-Emitting Diodes

Abstract

The stability of metal halide perovskite (CsPbX3, X = Cl, Br, and I) nanocrystals (NCs) is crucial for their practical applications. In this paper, perovskite NCs were synthesized in situ in lead-based metal–organic frameworks (Pb-MOFs: [Pb2(1,3,5-HBTC)2(H2O)4]·H2O), and we obtained stable and bright luminescence composites with different colors. Namely, CsPbBr3@Pb-MOF composites were created by the in situ growth of CsPbBr3 crystals (NCs) on Pb-MOF, which had high ion resistance, bright photoluminescence (PL), and excellent stability. The composites still had bright luminescence after 11 months of storage. The PL intensity of green-emitting CsPbBr3@Pb-MOF composites was increased compared with as-prepared CsPbBr3 NCs. Bright and stable blue- and red-emitting CsPbX3@Pb-MOF composites were obtained by adjusting the amount of PbX2 (X = Cl, Br, and I) in the synthesis process. These CsPbX3 NCs were homogeneously distributed in Pb-MOF substrates. The growth of CsPbX3 NCs in Pb-MOFs prevented NC aggregation and decreased surface defects against nonradiative recombination during emitting. Thus, the PL lifetime and stability were improved. Furthermore, white light-emission diodes were prepared using three color CsPbX3@Pb-MOF composites with Commission Internationale de I’Eclairage color coordinates of (0.296, 0.316). This result provided an efficient way to overcome the limitation of chemical solution synthesis and improve the stability of CsPbX3 NCs.

Dual-Mode Luminous Lead-Free Cs3Cu2Cl5 Perovskite Embedded in UiO-66-NDC Nanoparticles for Multilevel Anti-Counterfeiting

“…Moreover, the functional groups of Cs 3 Cu 2 Cl 5 , UiO-66-NDC, and CCL 4 /UiO were investigated by Fourier transform infrared (FT-IR) spectroscopy, and the spectra are shown in Figure c. For the pure Cs 3 Cu 2 Cl 5 NCs, the absorption peaks observed at 1636 cm –1 (N–H), 1710 cm –1 (CO), 3444 cm –1 (N–H vibrations), 1464 cm –1 (−CH 2 vibrational), and 2852 and 2926 cm –1 (asymmetric C–H stretching) are ascribed to the long-chain organic ligand, , indicating the existence of oleic acid and oleylamine on the surface of the Cs 3 Cu 2 Cl 5 NCs. Notably, all of the absorption peaks corresponding to Cs 3 Cu 2 Cl 5 NCs were also observed in the spectrum of the CCL 4 /UiO nanocomposite, and the absorption bands originating from UiO-66-NDC were clearly observed in the composites as well, further verifying the successful embedment of the NCs in the UiO-66-NDC matrix.…”

CsPbX3 (X = Cl, Br, and I) Nanocrystals in Substrates toward Stable Photoluminescence: Nanoarchitectonics, Properties, and Applications

“…(g) XRD patterns obtained for Pb-MOFs and CsPbBr 3 @Pb-MOF. All panels are reproduced from ref . Copyright 2022 American Chemical Society.…”

“…79 Recently, we reported on the in situ synthesis of perovskite NCs in Pb-MOFs (CsPbBr 3 @Pb-MOF composites via the in situ growth of CsPbBr 3 NCs on Pb-MOFs) to attain improved stability and brightness as well as high ion resistance. 18 Figure 3a shows a schematic illustration of the detailed preparation process. Based on our previous results, it was obvious that compared to other MOFs, the white Pb-MOF powder matrix showed great potential for providing Pb 2+ sites for the in situ growth of the CsPbBr 3 NCs and enhancing the PL density of the CsPbBr 3 @ Pb-MOF composites.…”

“…Based on our previous results, it was obvious that compared to other MOFs, the white Pb-MOF powder matrix showed great potential for providing Pb 2+ sites for the in situ growth of the CsPbBr 3 NCs and enhancing the PL density of the CsPbBr 3 @ Pb-MOF composites. 18 Figure 3b shows a TEM image of this PbBr 3 @Pb-MOF composite demonstrating that the Pb-MOF matrix possesses irregular rectangular morphology. According to the higher-magnification TEM data obtained for CsPbBr 3 @Pb-MOF composites shown in Figure 3c to 3e, the homogeneous dispersion of CsPbBr 3 NCs on Pb-MOFs indicated that the Pb sites on Pb-MOFs were the key to attaining in situ growth of the CsPbBr 3 NCs (with an average particle size of about 5 nm).…”

Highly Stable CsPbBr3 Perovskite Nanocrystals Encapsulated in Metal–Organic Frameworks for White Light-Emitting Diodes

“…Metal–organic frameworks (MOFs) have widespread applications in catalysis, gas separation, photoreduction, and other fields for their ability to control the arrangement and chemistry of the guest molecules in their pores. Preliminary studies showed that the degradation of CsPbX 3 can be noticeably slowed down by embedding the perovskite NCs inside the MOF. − To further enhance the passivation efficacy, the pores of the MOF have to be sealed via a high temperature process so as to completely isolate the embedded NCs from the surroundings. However, common MOF materials like zeolitic imidazolate framework-8 (ZIF-8) usually decompose before melting when heated .…”