High Resolution Mapping of Two-Photon Excited Photocurrent in Perovskite Microplate Photodetector

Bin Yang; Junsheng Chen; Qi Shi; Zhengjun Wang; Marina Gerhard; Alexander Dobrovolsky; Ivan G Scheblykin; Khadga Jung Karki; Keli Han; Tõnu Pullerits

doi:10.1021/acs.jpclett.8b02250

High Resolution Mapping of Two-Photon Excited Photocurrent in Perovskite Microplate Photodetector

J Phys Chem Lett. 2018 Sep 6;9(17):5017-5022. doi: 10.1021/acs.jpclett.8b02250. Epub 2018 Aug 22.

Authors

Bin Yang^{1

2}, Junsheng Chen^{1

3}, Qi Shi³, Zhengjun Wang³, Marina Gerhard³, Alexander Dobrovolsky³, Ivan G Scheblykin³, Khadga Jung Karki³, Keli Han¹, Tõnu Pullerits³

Affiliations

¹ State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics (DICP) , Chinese Academy of Sciences , 457 Zhongshan Road , Dalian , Liaoning 116023 , China.
² University of the Chinese Academy of Sciences , Beijing 100039 , P. R. China.
³ Department of Chemical Physics and NanoLund, Chemical Center , Lund University , P.O. Box 124, 22100 Lund , Sweden.

PMID: 30124049
DOI: 10.1021/acs.jpclett.8b02250

Abstract

We fabricate photodetectors based on solution-processed single CH₃NH₃PbBr₃ microcrystals (MCs) and map the two-photon absorption (TPA) excited photocurrent (PC) with spatial resolution of 1 μm. We find that the charge carrier transport length in the MCs depends on the applied electric field, and increases from 5.7 μm for 0.02 V bias (dominated by carrier diffusion) to 23.2 μm for 2 V bias (dominated by carrier drift). Furthermore, PC shows strong spatial variations. Combining the PC mapping results with time-resolved photoluminescence microscopy, we demonstrate that the spatial distribution of PC mainly originates from the inhomogeneous distribution of trap-states across perovskite MCs. This suggests that there is still large margin for improvement of perovskite single crystal devices by better controlling of the traps.