Unveiling Ultrafast Carrier Extraction in Highly Efficient 2D/3D Bilayer Perovskite Solar Cells

• DOI: 10.1021/acsphotonics.2c00982
• Publication Date: 2022-10-21T17:16:33Z
• Authors: Mriganka Singh; I-Hung Ho; Anupriya Singh; Ching-Wen Chan; Jing-Wei Yang; Tzung-Fang Guo; Hyeyoung Ahn; Vincent Tung; Chih Wei Chu; Yu-Jung Lu
• Keywords: 02 engineering and technology; 0210 nano-technology; 01 natural sciences; 0104 chemical sciences

The development of multidimensional heterostructure (2D/3D) lead halide perovskites has emerged as an effective approach to enhancing the efficiency and long-term stability of perovskite solar cells (PSCs). However, a fundamental understanding of the working mechanisms, such as carrier extraction, and carrier transfer dynamics in the multidimensional perovskites heterostructures remains elusive. Here, we observe the ultrafast carrier extraction in highly efficient 2D/3D bilayer PSCs (power conversion efficiency of 21.12%) via femtosecond time-resolved pump–probe transient absorption spectroscopy (TAS). Notably, the formation of quasi-equilibrium states resulting in a subband absorption feature with an ultrafast lifetime of 440 fs was observed, and this feature is found only in 2D/3D perovskite heterostructure. The short-lived feature gives rise to the local electric-field-induced electroabsorption, resulting in an enhanced power conversion efficiency in 2D/3D PSCs. These findings can help comprehend the advanced working mechanism of highly efficient solar cells and other 2D/3D bilayer perovskite-based optoelectronic devices. ; The authors gratefully acknowledge the financial support of the National Science and Technology Council, Taiwan (NSTC 109-2112-M-001-043-MY3 (Y.J.L.), NSTC 110-2124-M-001-008-MY3 (Y.J.L.), NSTC 110-2124-MA49-009-MY3 (H.A.), and NSTC 111-2221-E-001-006 (C.W.C.)). This work was also supported by the Academia Sinica, Taiwan (AS-CDA-108-M08). V.T. is indebted to the support from the King Abdullah University of Science and Technology (KAUST) Office of Sponsored Research under Award (OSR-2018-CARF/CCF-3079). The data sets analyzed in this study are available from the corresponding author upon reasonable request.