Epitaxial Growth of CsPbX₃ (X = Cl, Br, I) Perovskite Quantum Dots via Surface Chemical Conversion of Cs₂GeF₆ Double Perovskites: A Novel Strategy for the Formation of Leadless Hybrid Perovskite Phosphors with Enhanced Stability

Abstract

LHPs are emerging as highly efficient light emitters with a narrow full width at half-maximum (FWHM) and tunable emission throughout the visible region (400-700 nm). [3] In particular, all inorganic cesium lead halide (CsPbX 3 , X = Cl, Br, I) perovskite quantum dots (QDs) with near-unity photoluminescence quantum yields (PLQYs) in the blue, green, and red regions and high color purity have been regarded as highly efficient narrow-band phosphors for lighting and next-generation displays devices. [4] Despite their excellent optical properties together with their impressive performance in various lighting fields, LHPs have received criticism because of the toxicity of lead and the lack of long-term stability. [5] Concerning the environmental issues, tin-, bismuth-, and antimony-based analogs such as CsSnX 3 , [6] Cs 3 Bi 2 X 9 , [7] and Cs 3 Sb 2 X 9 , [8] were developed to replace the toxic lead complexes, but both the PLQYs and the stability failed to meet the requirements of practical applications. For example, CsSnX 3 suffers from a low PLQY (0.14% for CsSnBr 3 QDs); simultaneously, it is highly sensitive to oxygen, which subsequently results in severe photoluminescence (PL) quenching. [6] Recently, silverbismuth-based Cs 2 AgBiX 6 double perovskites have attracted wide attention owing to their relatively higher stability. [5a,9] Nevertheless, the PLQY (6.7% for Cs 2 AgBiCl 6 QDs) is still limited. [9a] Similarly, tin(IV)-based Cs 2 SnX 6 double perovskites Lead halide perovskites (LHPs) have received increased attention owing to their intriguing optoelectronic and photonic properties. However, the toxicity of lead and the lack of long-term stability are potential obstacles for the application of LHPs. Herein, the epitaxial synthesis of CsPbX 3 (X = Cl, Br, I) perovskite quantum dots (QDs) by surface chemical conversion of Cs 2 GeF 6 double perovskites with PbX 2 (X = Cl, Br, I) is reported. The experimental results show that the surface of the Cs

Low‐Dimensional Metal Halide Perovskite Photodetectors

“…Some other novel strategies were also explored for 0D MHPs, and, for example, Wei et al reported the epitaxial synthesis of CsPbX 3 /Cs 2 GeF 6 hybrid NCs by partial surface chemical conversion of Cs 2 GeF 6 double perovskite with PbX 2 . [60] In addition, some researchers focus on top-down approaches for the synthesis of 0D nanostructures. For example, Huang et al synthesized MAPbBr 3 NCs by mixing precursors, MABr and PbBr 2 , with two ligands-OA and OLA.…”

0D Cs3Cu2X5 (X = I, Br, and Cl) Nanocrystals: Colloidal Syntheses and Optical Properties

“…However, the intrinsic toxicity of Pb 2+ and instability against light, moisture and heat, greatly hamper their commercial applications. To address these issues, one feasible strategy is to replace lead with other divalent nontoxic ions (e.g., tin and germanium), or with heterovalent ions to form lead‐free double‐perovskite NCs . However, the limited stability of Sn 2+ and Ge 2+ ions, and the low emission efficiency of double perovskite NCs are still hurdles to their further development.…”

Self‐Assembly of Completely Inorganic Perovskite Nanocrystals with Improved Stability by Anchoring on Kaolinite Lamellae

“…The high‐resolution spectrum of Br − ions was decomposed into two Gaussian bands with binding‐energy peaks at 68.6 and 67.9 eV, corresponding to 3d 3/2 and 3d 5/2 core levels of Br − ions (Figure f). The atomic ratio of Cs/Pb/Br was constant at about 1:1:3, indicating the preservation of stoichiometry for CsPbBr 3 . The signal intensity of the Si and O elements cannot be considered evidence for interference by the Si substrate, but that of Al coincides with pure kaolinite (Figure g).…”