Highly Stable n–i–p Structured Formamidinium Tin Triiodide Solar Cells through the Stabilization of Surface Sn2+ Cations

Hu M, Risqi AM, Wu J, Chen L, Park J, Lee SU, Yun HS, Park BW, Brabec C, Seok SI (2023)

Publication Type: Journal article

Publication year: 2023

Journal

Advanced Functional Materials Wiley-VCH Verlag

DOI: 10.1002/adfm.202300693

Abstract

Improving the performance, reproducibility, and stability of Sn-based perovskite solar cells (PSCs) with n–i–p structures is an important challenge. Spiro-OMeTAD [2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenyl-amine)9,9′-spirobifluorene], a hole transporting material (HTM) with n–i–p structure, requires the oxygen exposure after addition of Li-TFSI [Lithium bis(trifluoromethanesulfonyl)imide] as a dopant to increase the hole concentration. In Sn-based PSC, Sn²⁺ is easily oxidized to Sn⁴⁺ under such a condition, resulting in a sharp decrease in efficiency. Herein, a formamidinium tin triiodide (FASnI3)-based PSCs fabricated using DPI-TPFB [4-Isopropyl-4′-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate] instead of Li-TFSI are reported as a dopant in Spiro-OMeTAD. The DPI-TPFB enables the fabrication of PSCs with an efficiency of up to 10.9%, the highest among FASnI3-based PSCs with n–i–p structures. Moreover, ≈80% of the initial efficiency is maintained even after 1,597 h under maximum power point tracking conditions. In particular, the encapsulated device does not show any decrease in efficiency even after holding for 50 h in the 85 °C/85% RH condition. The high efficiency and excellent stability of PSCs prepared by doping with DPI-TPFB are attributed to not only increasing electrical conductivity by acting as a Lewis acid, but also stabilizing Sn²⁺ through coordination with Sn²⁺ on the surface of FASnI3.

Authors with CRIS profile

Jianchang Wu Institute Materials for Electronics and Energy Technology (i-MEET) Christoph Brabec Institute Materials for Electronics and Energy Technology (i-MEET)

Involved external institutions

Ulsan National Institute of Science and Technology (UNIST) / 울산과학기술원

Korea, Republic of (KR)

How to cite

APA:

Hu, M., Risqi, A.M., Wu, J., Chen, L., Park, J., Lee, S.U.,... Seok, S.I. (2023). Highly Stable n–i–p Structured Formamidinium Tin Triiodide Solar Cells through the Stabilization of Surface Sn2+ Cations. Advanced Functional Materials. https://doi.org/10.1002/adfm.202300693

MLA:

Hu, Manman, et al. "Highly Stable n–i–p Structured Formamidinium Tin Triiodide Solar Cells through the Stabilization of Surface Sn2+ Cations." Advanced Functional Materials (2023).

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