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Qinying Pan. Portrait.

Qinying Pan

Postdoctoral fellow

Qinying Pan. Portrait.

Imidazole additives in 2D halide perovskites : impacts of -CN versus -CH3 substituents reveal the mediation of crystal growth by phase buffering

Author

  • Shuang Yu
  • Jie Meng
  • Qinying Pan
  • Qian Zhao
  • Tõnu Pullerits
  • Yingguo Yang
  • Kaibo Zheng
  • Ziqi Liang

Summary, in English

The unique sandwich structure and favorable crystallization kinetics have endowed two-dimensional (2D) halide perovskites with excellent ambient stability and facile film formation compared to those of their three-dimensional counterparts. However, the heterogeneous crystallization of multiple n-value phases during solution-casting of 2D perovskite thin films results in random and disordered crystalline alignment in conjunction with numerous lattice defects, all of which ultimately impair the device performance. Herein we demonstrate that highly ordered lattice arrangements in 2D lead halide perovskites, exemplified as a paradigm phenylethylamine (PEA) spacer, can be achieved using the 4,5-dicyanoimidazole (DCI) additive without any post-treatment. Electrostatic potential distribution mapping and X-ray photoelectron spectroscopy collectively confirm the Lewis acid-base interaction between -CN− units in DCI and Pb2+, which is conducive to homogeneous nucleation during perovskite crystallization. A sequence of in situ grazing-incident wide-angle X-ray scattering and high-resolution transmission electron microscopy characterization unravel the epitaxial growth of multi-phases that gradually buffer the internal lattice strain and consequently regulate the lattice orientation, which markedly leads to a reduction of trap density and a prolongation of carrier lifetime. The resulting planar solar cells based on 2D PEA2MA3Pb4I13 (n = 4) deliver an outstanding efficiency of ∼17.0% along with excellent operational stability.

Department/s

  • LTH Profile Area: Nanoscience and Semiconductor Technology
  • Chemical Physics
  • LTH Profile Area: Photon Science and Technology
  • NanoLund: Centre for Nanoscience

Publishing year

2022-06-07

Language

English

Pages

3321-3330

Publication/Series

Energy and Environmental Science

Volume

15

Issue

8

Document type

Journal article

Publisher

Royal Society of Chemistry

Topic

  • Inorganic Chemistry

Status

Published

ISBN/ISSN/Other

  • ISSN: 1754-5692