How antisolvent miscibility affects perovskite film wrinkling and photovoltaic properties

Seul-Gi Kim,Jeong-Hyeon Kim,Fabian Panzer,Yu Zhong,Konstantin Schötz,Philipp Ramming,Sven Huettner,Seok Joon Kwon,Nam-Gyu Park

doi:10.1038/s41467-021-21803-2

Seul-Gi Kim, Jeong-Hyeon Kim + Show 7 more

Open Access

https://doi.org/10.1038/s41467-021-21803-2

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Abstract

Charge carriers’ density, their lifetime, mobility, and the existence of trap states are strongly affected by the microscopic morphologies of perovskite films, and have a direct influence on the photovoltaic performance. Here, we report on micro-wrinkled perovskite layers to enhance photocarrier transport performances. By utilizing temperature-dependent miscibility of dimethyl sulfoxide with diethyl ether, the geometry of the microscopic wrinkles of the perovskite films are controlled. Wrinkling is pronounced as temperature of diethyl ether (TDE) decreases due to the compressive stress relaxation of the thin rigid film-capped viscoelastic layer. Time-correlated single-photon counting reveals longer carrier lifetime at the hill sites than at the valley sites. The wrinkled morphology formed at TDE = 5 °C shows higher power conversion efficiency (PCE) and better stability than the flat one formed at TDE = 30 °C. Interfacial and additive engineering improve further PCE to 23.02%. This study provides important insight into correlation between lattice strain and carrier properties in perovskite photovoltaics.

Highlights

Charge carriers’ density, their lifetime, mobility, and the existence of trap states are strongly affected by the microscopic morphologies of perovskite films, and have a direct influence on the photovoltaic performance
We extend a scope of the study to the investigation of the effects of the microscopic wrinkles on the charge carrier dynamics with timecorrelated single-photon counting (TCSPC) coupled with fluorescence lifetime imaging microscopy (FLIM) and photoconductive atomic force microscope
The cross-sectional profile of the microscopic wrinkles can be represented as a sinusoidal curve with a wavelength (λ) and an amplitude (A). λ is estimated by calculating the governing characteristic periodic length scales from the 2D Fourier transform of optical microscope images (Supplementary Fig. 1) and A by calculating the average height difference between the hill and the valley such that A =/2

Summary

Introduction

Charge carriers’ density, their lifetime, mobility, and the existence of trap states are strongly affected by the microscopic morphologies of perovskite films, and have a direct influence on the photovoltaic performance. We report a simple and yet effective experimental approach to control and optimize the microscopic geometry of the wrinkles of perovskite thin films to maximize the photovoltaic performances, as well as long-time durability.

Results

Conclusion