Dresden 2020 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 45: Hybrid Perovskite and Photovoltaics I (joint session CPP/HL)

HL 45.10: Talk

Wednesday, March 18, 2020, 12:00–12:15, ZEU 260

Photodoping through local charge carrier accumulation in alloyed hybrid perovskites for highly efficient luminescence — •Sascha Feldmann, Stuart Macpherson, Satyaprasad Senanayak, Mojtaba Abdi-Jalebi, Jasmine Rivett, Guangjun Nan, Gregory Tainter, Tiarnan Doherty, Kyle Frohna, Emilie Ringe, Richard Friend, Henning Sirringhaus, Michael Saliba, David Beljonne, Samuel Stranks, and Felix Deschler — Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom

Metal-halide perovskites have emerged as exceptional semiconductors for optoelectronic applications. Substitution of the monovalent cations has advanced luminescence yields and device efficiencies. Here, we control the cation alloying to enhance optoelectronic performance through alteration of the charge carrier dynamics in mixed-halide perovskites. In contrast to single-halide perovskites, we find high luminescence yields for photo-excited carrier densities far below solar illumination conditions. Using time-resolved spectroscopy we show that the charge-carrier recombination regime changes from second to first order within the first tens of nanoseconds after excitation. Supported by microscale-mapping of the optical bandgap, electrically-gated transport measurements and first-principles calculations, we demonstrate that spatially-varying energetic disorder in the electronic states causes local charge accumulation, creating p- and n-type photo-doped regions, which unearths a strategy for efficient light emission at low charge-injection in solar cells and LEDs.