Researchers Find Low-Frequency Lattice Phonons in Halide Perovskites Resulting in High Defect
A research group guided by Prof. Zhao Jin from the Physics Department, University of Science and Technology of China (USTC) of the Chinese Academy of Sciences (CAS) discovered low-frequency lattice phonons in halide perovskites leading to high defect tolerance toward electron-gap recombination with their independently-developed software, Hefei-NAMD. The study revealed in Science Advances.
Solar cells have been wildly utilized in various livelihood or industrial applications, while the effectivity and sturdiness of photovoltaic energy semiconductors still irritate producers.
Errors in semiconducting materials type electron-gap recombination facilities detrimental to photovoltaic conversion efficiency.
As early as the Fifties, the scientists Shockley, Read, and Hall proposed the well-known Shockley-Read-Hall (SRH) model through which error states in the bandgap form e-h recombination facilities. For decades, the abstract model has been tailored by many researchers in the semiconducting area.
Nevertheless, it doesn’t account for the electron-phonon coupling, which is the key for e-h recombination by nonradiative processes.
In this research, the scientists investigated the e-h recombination processes due to native level errors in methylammonium lead halide (MAPbI3) perovskites utilizing ab initio nonadiabatic molecular dynamics and taking components in count resembling electron-phonon interactions, energy levels, nuclear velocity, decoherence results and carrier focus.
They discovered that charge recombination in MAPbI3 was not enhanced no matter whether the errors introduce a deep band state, which meant the SRH principle lapsed.
These findings are vital in the future design of functional semiconducting supplies for photovoltaic energy conversion.