Spectroscopic Insight into Efficient and Stable Hole Transfer at the Perovskite/Spiro-OMeTAD Interface with Alternative Additives.
ACS APPLIED MATERIALS & INTERFACES 2021;
13:5752-5761. [PMID:
33470096 DOI:
10.1021/acsami.0c19111]
[Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A stable and efficient carrier transfer is a prerequisite for high-performance perovskite solar cells. With optimized additives, a significantly improved charge carrier transfer can be achieved at the interface of perovskite/2,2',7,7'-tetrakis-(N,N-di-4-methoxyphenylamino)-9,90-spirobifluorene (Spiro-OMeTAD) with significantly boosted photostability. Using time-dependent spectroscopic techniques, we investigated charge carrier and mobile-ion dynamics at the perovskite/Spiro-OMeTAD interface, where the Spiro-OMeTAD contains different bis(trifluoromethanesulfonyl)imide (TFSI) salts additives (Li-TFSI, Mg-TFSI2, Ca-TFSI2). The pristine response and the dynamic changes under continuous illuminations are presented, which is correlated to the different behaviors of mobile-ion accumulations at the perovskite/Spiro interface and ascribed to the improved hole mobilities in Spiro-OMeTAD, ultimately contributing to the favorable behaviors in solar cells. It is demonstrated that the hole mobility and conductivity of hole transport layers play an important role in suppressing mobile-ion accumulation at the interfaces of solar cells. With the engineering of mixed-cation mixed-halide perovskite, optimal engineering of additives in hole transport materials is an efficient strategy. Therefore, it should be emphasized for accelerating perovskite photovoltaic commercialization.
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