Phys.org July 17, 2024
To understand the transport of photoexcited charge carriers for designing next-generation light-harvesting devices an international team of researchers (Germany, UK) simultaneously probed the intrinsic out-of-plane charge-carrier diffusion and the nanoscale morphology of the organic–inorganic metal halide perovskite FA0.83Cs0.17Pb(I1−xClx)3 by pushing depth-sensitive terahertz near-field nanospectroscopy to extreme subcycle timescales. By analysing deep-subcycle time shifts of the scattered terahertz waveform after photoexcitation, they accessed the vertical charge-carrier dynamics within single grains. At all the measured locations, despite topographic irregularities, diffusion was homogeneous on the 100 nm scale, although it varied between mesoscopic regions. According to the researchers linking in situ carrier transport with nanoscale morphology and chemical composition could introduce a paradigm shift for the analysis and optimization of next-generation optoelectronics that are based on nanocrystalline materials… read more. TECHNICAL ARTICLE
Pump-induced near-field response of the perovskite film. Credit: Nature Photonics, 17 July 2024