Resonance Raman and Excitation Energy Dependent Charge Transfer Mechanism in Halide-Substituted Hybrid Perovskite Solar Cells
Citations Over TimeTop 1% of 2015 papers
Abstract
Organo-metal halide perovskites (OMHPs) are materials with attractive properties for optoelectronics. They made a recent introduction in the photovoltaics world by methylammonium (MA) lead triiodide and show remarkably improved charge separation capabilities when chloride and bromide are added. Here we show how halide substitution in OMHPs with the nominal composition CH3NH3PbI2X, where X is I, Br, or Cl, influences the morphology, charge quantum yield, and local interaction with the organic MA cation. X-ray diffraction and photoluminescence data demonstrate that halide substitution affects the local structure in the OMHPs with separate MAPbI3 and MAPbCl3 phases. Raman spectroscopies as well as theoretical vibration calculations reveal that this at the same time delocalizes the charge to the MA cation, which can liberate the vibrational movement of the MA cation, leading to a more adaptive organic phase. The resonance Raman effect together with quantum chemical calculations is utilized to analyze the change in charge transfer mechanism upon electronic excitation and gives important clues for the mechanism of the much improved photovoltage and photocurrent also seen in the solar cell performance for the materials when chloride compounds are included in the preparation.
Related Papers
- → Organolead Halide Perovskite: New Horizons in Solar Cell Research(2014)709 cited
- → Halide-Dependent Electronic Structure of Organolead Perovskite Materials(2015)365 cited
- → Machine learning for halide perovskite materials(2020)118 cited
- → Aggregation of molecular halide perovskite Cs4PbX6: A first-principles investigation(2019)7 cited
- → Modifying Optoelectronic Properties of Molecular Halide Perovskite Cs4PbBr6 via Organic Ligands: A First-Principles Investigation(2021)