Optoelectronic applications have been very popular for organic-inorganic hybrid metal halid perovskites (MHPs). MHPs were recently used to design cost-effective solar cells and solid-state lighting. The material promises many things, but there are still many questions about the nature and mobility charge carriers in MHPs. This requires further research.
Researchers at the University of Shanghai for Science and Technology have now reported photoinduced large-polaron transport and dynamics in organic and inorganic hybrid lead haide perovskite. They collaborate with Qingdao Institute of Bioenergy and Bioprocess Technology, Shanghai University and Shanghai Institute of Technical Physics.
The researchers experimentally identify the photocarriers-optical phonon coupling in CH3NH3PbI3 (MAPbI3) polycrystalline grains, by using optical-pump and terahertz-electromagnetic probe spectroscopy. The photoinduced charge carrier forms a quasi-particle, which is a polaron, due to the lattice distortion resulting from several lattice constants. The researchers calculate the scattering and effective mass of photogenerated polaronic carrier using the Drude Smith-Lorentz model. The large polaron mobility can be calculated based on the polaron mass enhancement and the presence or defects in the material.
Researchers also discovered that large polarons are formed in MAPbI3 to protect charge carriers against scattering due to polycrystalline grain boundaries and defects. This explains the long life span of photoconductivity. These findings are relevant to both fundamental researches as well as device applications. These results were published in Light: Science & Applications.
