Atomic Insights of Stable, Monodispersed CsPbI3−xBrx (x = 0, 1, 2, 3) Nanocrystals Synthesized by Modified Ligand Cell. (26th May 2022)

• Record Type: Journal Article
• Authors: Ghorai, Arup; Mahato, Somnath; Srivastava, Sanjeev Kumar; Ray, Samit K.
• Is Part Of: Advanced functional materials. Volume 32:Number 32(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-05-26
• Subjects: atomic resolution TEM -- caesium lead halide perovskites -- colloidal syntheses -- density functional theory -- inverted perovskite solar cells; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.202202087
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: Synthesis of monodispersed, stable halide, and mixed halide perovskite nanocrystals by hot‐injection approach is still challenging due to the fast reaction kinetics and unrevealed ligand chemistry. The atomic scale imaging of perovskite nanocrystals using transmission electron microscopy (TEM) is also challenging because of their structural degradation due to high electron dose and soft nature of perovskites. Here, a novel technique is proposed to synthesize pure cubic phase, monodispersed, stable CsPbX3 (X = I/Br) nanocrystals by simply modifying ligand chemistry using olive oil, which also leads to realization of tuneable composition mixed halide perovskites by simple physical mixing. Here, the atomic scale images and the probable distribution of Cs, Pb, and I/Br atoms in single halide and mixed halide perovskites via high‐resolution TEM microscopy are presented. The estimated atomic distance (PbPb and PbI/Br) is strongly corroborated with the VESTA structure. Interestingly, the lattice constant ( d ‐value) of the synthesized nanocrystals is smaller (≈3%) than the theoretical predicted one, leading to a higher phase stability in laboratory ambient conditions (45–55% humidity, 300 K). The theoretical analysis using density functional theory enlightens the understanding of higher stability of CsPbI2 Br along with the maximum optical absorption in the visible regime, as a preferable material for the photovoltaic applications. Abstract : Here, colloidal synthesis of monodisperse cubic CsPbI3 nanocrystals by modifying ligand cell with high reproducibility using olive oil is proposed. Atomic scale imaging of single halide and mixed halide perovskite (CsPbBr x I3− x, x = 0, 1, 2, 3) nanocrystals for inverted perovskite solar cell, fabricated under ambient condition (45–55% humid condition), is presented.