Fluorescence spectroscopy-based study of balanced transport of charge carriers in hot-air-annealed perovskites

In-Wook Hwang; Yanliang Liu; Sung Heum Park

doi:10.1016/j.saa.2018.09.005

Fluorescence spectroscopy-based study of balanced transport of charge carriers in hot-air-annealed perovskites

Spectrochim Acta A Mol Biomol Spectrosc. 2019 Jan 15:207:68-72. doi: 10.1016/j.saa.2018.09.005. Epub 2018 Sep 4.

Authors

In-Wook Hwang¹, Yanliang Liu², Sung Heum Park²

Affiliations

¹ Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, Gwangju 500-712, South Korea. Electronic address: hwangiw@gist.ac.kr.
² Department of Physics, Pukyong National University, Busan 48513, South Korea; Hybrid Interface Materials Global Frontier Research Group, Pusan National University, Busan 46241, South Korea.

PMID: 30195929
DOI: 10.1016/j.saa.2018.09.005

Abstract

Using fluorescence spectroscopy, we investigate the transport of charge carriers in (p-i-n) planar perovskite (CH₃NH₃PbI_3-xCl_x) solar cells with the structure ITO/PEDOT:PSS/perovskites/PCBM/Ca/Al, in which the perovskite morphology is optimized by moisture pretreatment (MPT) and the hot-air-annealing process (HAAP). After annealing with hot air, the electron transport time of the perovskites is shortened by a factor of 3.6 (from 28.8 to 7.9 ns), eventually leading to balanced transport of electrons and holes (characterized by the fluorescence-decay time constants of 7.9 and 7.6 ns, respectively). These results are in good agreement with the observed increase in the photovoltaic conversion efficiency.

Keywords: Charge carrier transport; Fluorescence; Perovskite; Solar cell; Time-resolved.