Phase Regulation of CsPb₂Br₅/CsPbBr₃ Perovskite Nanocrystals by Doping with Divalent Cations: Implications for Optoelectronic Devices with Enhanced Stability and Reduced Toxicity

Abstract

Inorganic metal halide perovskites are generally considered as highly attractive materials for optoelectronic application devices. Unfortunately, Pb-based perovskite nanocrystals (NCs) are unstable because of their sensitivity to water, oxygen, light, and thermal treatment, which seriously limits their practical application. Herein, the dual-phase CsPb2Br5/CsPbBr3 NCs were synthesized first, and then the dual-phase M2+-doped CsPb2Br5/CsPbBr3 NCs (M = Ca2+, Sr2+, and Ba2+) with low toxicity were simply and rapidly prepared at room temperature based on the CsPb2Br5/CsPbBr3 NCs. The Sr2+-doped samples show outstanding stability and photoluminescence quantum yield due to the elimination of structural distortion and lattice contraction caused by the almost equal radii of Sr2+ (1.18 Å) and Pb2+ (1.19 Å). Interestingly, with the increase in M2+ concentration, the dual-phase quasi-2D tetragonal CsPb2Br5/CsPbBr3 NCs gradually transformed into single-phase 3D cubic Cs­(Pb/M)­Br3. These high-performance perovskite luminescent materials are expected to be used in light-emitting devices and other optoelectronic devices.

Synergistic binding between an engineered interface and functionalized ferrocene offers remarkable charge extraction efficiency in lead halide perovskites

“…The dual-phase existence of CPB NK-12 was further conrmed by TEM analysis, with lattice spacing values of 5.8 Å (100), 4.1 Å (110), and 2.9 Å (200) for cubic CPB, and 6.0 Å (110), 4.2 Å (200), 2.8 Å (300), and 3.2 Å (213) for tetragonal CP 2 B 5 . [67][68][69] The average sizes of CPB and CPB NK-12 calculated using the DLS number-size distribution were found to be ∼9 nm and ∼149 nm, respectively (Fig. S2a †).…”

Transition metal(ii) ion doping of CsPb2Br5/CsPbBr3 perovskite nanocrystals enables high luminescence efficiency and stability

“…Deng et al have recently synthesized dual phase Sb 3+ or Sr 2+ -doped CsPb 2 Br 5 /CsPbBr 3 NCs, both of which showed improved stability and high PLQYs. 21,22 Although the doping strategy has been briefly applied in inorganic perovskite NCs in order to mitigate the material degradation for luminous applications, 23 the material instability of perovskite NCs under water and heat conditions is still a great barrier for future applications. Therefore, it is highly desirable to develop universal strategies to enhance the reliability of perovskite NCs.…”

Enhanced emission efficiency in doped CsPbBr3 perovskite nanocrystals: the role of ion valence

“…32 The Sr 2+ doped dual-phase quasi-two dimensional tetragonal CsPb 2 Br 5 / CsPbBr 3 NCs showed high PLQY and outstanding stability. 33 Additionally, colloidal CsPbBr 3 perovskite NCs with heterovalent Bi 3+ ions were developed by an in situ doping approach.…”

“…32 The Sr 2+ doped dual-phase quasi-two dimensional tetragonal CsPb 2 Br 5 /CsPbBr 3 NCs showed high PLQY and outstanding stability. 33 Additionally, colloidal CsPbBr 3 perovskite NCs with heterovalent Bi 3+ ions were developed by an in situ doping approach. The PLQY of Bi 3+ -doped CsPbBr 3 NCs trended downward, but the incorporation of Bi 3+ precisely tuned their band structure and excited-state dynamics.…”