Surface Ligand Management Aided by a Secondary Amine Enables Increased Synthesis Yield of CsPbI3 Perovskite Quantum Dots and High Photovoltaic Performance

Yao Wang; Jianyu Yuan; Xuliang Zhang; Xufeng Ling; Bryon W Larson; Qian Zhao; Yingguo Yang; Yao Shi; Joseph M Luther; Wanli Ma

doi:10.1002/adma.202000449

Surface Ligand Management Aided by a Secondary Amine Enables Increased Synthesis Yield of CsPbI₃ Perovskite Quantum Dots and High Photovoltaic Performance

Adv Mater. 2020 Aug;32(32):e2000449. doi: 10.1002/adma.202000449. Epub 2020 Jul 1.

Authors

Affiliations

¹ Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Soochow University, 199 Ren-Ai Road, Suzhou Industrial Park, Suzhou, 215123, P. R. China.
² Chemistry and Nanoscience Department, National Renewable Energy Laboratory, Golden, CO, 80401, USA.
³ Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201204, P. R. China.

PMID: 32609406
DOI: 10.1002/adma.202000449

Abstract

Lead-halide perovskite quantum dots (PQDs) or more broadly, nanocrystals possess advantageous features for solution-processed photovoltaic devices. The nanocrystal surface ligands play a crucial role in the transport of photogenerated carriers and ultimately affect the overall performance of PQD solar cells. Significantly improved CsPbI₃ PQD synthetic yield and solar-cell performance through surface ligand management are demonstrated. The treatment of a secondary amine, di-n-propylamine (DPA), provides a mild and efficient approach to control the surface ligand density of PQDs, which has an apparently different working mechanism compared to previously reported surface treatments. Using an optimal DPA concentration, the treatment can simultaneously remove both long-chain insulating surface ligands of oleic acid and oleylamine, even for unpurified PQDs with high ligand density. As a result, the electrical coupling between PQDs is enhanced, leading to improved charge transport, reduced carrier recombination, and a high power conversion efficiency approaching 15% for CsPbI₃ -PQD-based solar cells. In addition, the production yield of CsPbI₃ PQDs can be increased by a factor of 8. These results highlight the importance of developing new ligand-management strategies, specifically for emerging PQDs to achieve scalable and high-performance perovskite-based optoelectronic devices.

Keywords: CsPbI 3 quantum dots; di-n-propylamine; perovskite solar cells; surface ligand engineering.

Abstract

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