Mixed-Solvent Polarity-Assisted Phase Transition of Cesium Lead Halide Perovskite Nanocrystals with Improved Stability at Room Temperature

Abstract

Cesium lead halide perovskite nanocrystals (NCs) have attracted enormous interest in light-emitting diode, photodetector and low-threshold lasing application in terms of their unique optical and electrical performance. However, little attention has been paid to other structures associated with CsPbBr3, such as CsPb2Br5. Herein, we realize a facile method to prepare dual-phase NCs with improved stability against polar solvents by replacing conventional oleylamine with cetyltrimethyl ammonium bromide (CTAB) in the reprecipitation process. The growth of NCs can be regulated with different ratios of toluene and ethanol depending on solvent polarity, which not only obtains NCs with different sizes and morphologies, but also controls phase transition between orthorhombic CsPbBr3 and tetragonal CsPb2Br5. The photoluminescence (PL) and defect density calculated exhibit considerable solvent polarity dependence, which is ascribed to solvent polarity affecting the ability of CTAB to passivate surface defects and improve stoichiometry in the system. This new synthetic method of perovskite material will be helpful for further studies in the field of lighting and detectors.

Competitive Displacement Triggering DBP Photoelectrochemical Aptasensor via Cetyltrimethylammonium Bromide Bridging Aptamer and Perovskite

“…The methyl functional groups were rocking at 905 cm –1 . The band at 622 cm –1 was from the wagging bending of N–H. , It is worth noting that a peak at 1051 cm –1 that originated from the C–N stretching vibrations in CTAB molecules was observed in CTAB@CH 3 NH 3 PbI 3 . The intensity of 2973, 1602, and 1464 cm –1 peaks increased after the addition of CTAB.…”

Shining Light on the Structure of Lead Halide Perovskite Nanocrystals

“…101−103 However, the rational usage of polar solvent in the colloidal synthesis or post-treatment can bring about some significant changes, such as improved optical properties, 104 controlled size and shape, 51,105 and phase transition. 106 For instance, introducing a suitable amount of water in the reaction of CsPbBr 3 NCs induces the formation of different morphologies, like spherical NCs, rectangular nanosheets, or NWs; 105 using toluene and ethanol with different ratios as the mixed solvent can change the size and morphologies of CsPbBr 3 NCs, as well as control the phase transition between the orthorhombic CsPbBr 3 and tetragonal CsPb 2 Br 5 . 106 The in-depth investigation on how polar solvent induces lattice distortion of CsPbI 3 NCs was conducted by Wan et al 51 The aberration corrected STEM (AC-STEM) technique can confirm the structural distortion.…”

“…The decomposition process driven by water or humid air can be divided into several steps. Like MAPbI 3 , the absorbing water molecules can form hydrous intermediate phases first, and then degrade to HI, CH 3 NH 2 , and PbI 2 . − Recently, various strategies, including surface modification, core–shell structure, and polymer capping, have been developed to avoid the rapid degradation of HPs when exposed to polar solvent. − However, the rational usage of polar solvent in the colloidal synthesis or post-treatment can bring about some significant changes, such as improved optical properties, controlled size and shape, , and phase transition . For instance, introducing a suitable amount of water in the reaction of CsPbBr 3 NCs induces the formation of different morphologies, like spherical NCs, rectangular nanosheets, or NWs; using toluene and ethanol with different ratios as the mixed solvent can change the size and morphologies of CsPbBr 3 NCs, as well as control the phase transition between the orthorhombic CsPbBr 3 and tetragonal CsPb 2 Br 5 …”

ABX3 inorganic halide perovskites for solar cells: chemical and crystal structure stability

“…A variable to take into account is the temperature, since the photoactive phases are favored at high values, as shown in Figure 4. However, at room temperature the most stable phase (orthorhombic) is photovoltaically inactive [6,83,84].…”

“…Modification of components A B or X has been the first route to follow to increase the chemical and structural stability of perovskites, either by the total or partial replacement of any of its components, or by doping that relaxes the structural stress. Efforts have also been focused on optimizing the processes for obtaining these structures, controlling heat treatment, grain size, and the use of both organic and inorganic additives [32, [84][85][86][87][88][89][90].…”