Buried Interface Modification for Reduced Open-Circuit Voltage Loss in Perovskite Solar Cells With Efficiency Exceeding 25.8%

Weiwei Sun; Kexiang Wang; Weifeng Liu; Yansheng Sun; Yukun Gao; Tingting You; Hong Lian; Xiaofeng Huang; Shuanglong Wang; Penggang Yin

doi:10.1002/cnl2.70042

Buried Interface Modification for Reduced Open-Circuit Voltage Loss in Perovskite Solar Cells With Efficiency Exceeding 25.8%

Weiwei Sun
, Kexiang Wang
, Weifeng Liu
, Yansheng Sun
, Yukun Gao
, Tingting You^*
, Hong Lian^*
, Xiaofeng Huang
, Shuanglong Wang^*
, Penggang Yin^*

^*Corresponding author for this work

Department of Chemistry

Research output: Journal Publications and Reviews › RGC 21 - Publication in refereed journal › peer-review

15 Citations (Scopus)

6 Downloads (CityUHK Scholars)

Abstract

In n–i–p perovskite solar cells (PSCs), the buried interface of the perovskite layer is crucial for boosting both performance and stability. Here, multifunctional small molecule potassium trifluoromethanesulfonate (TFSK) is employed as an interlayer to efficiently bridge SnO₂ and the buried perovskite film, simultaneously regulating interfacial energetics and morphology. This strategy provides several advantages: (1) TFSK passivates oxygen vacancy defects and surface hydroxyl groups on SnO₂, while also improving energy level alignment; (2) TFSK modification induces a loose and porous morphology in PbI₂, facilitating the diffusion of ammonium salts and promoting sufficient ionic reactions to high-quality FAPbI₃ films; (3) TFSK interacts strongly with perovskite through Lewis acid–base interaction (between S=O groups and uncoordinated Pb²⁺) and hydrogen bonding (between F⁻and formamidinium cations), significantly suppressing non-radiative recombination. Consequently, the quality of both SnO₂ and perovskite films is significantly improved, which greatly boosts the power conversion efficiency of small-size PSCs to 25.82%, with a high open-circuit voltage of 1.19 V, a minimal voltage loss of 0.341 V, and negligible hysteresis. Moreover, the optimized SnO₂/TFSK-based PSCs demonstrate improved storage, humidity, and thermal stability.

© 2025 The Author(s). Carbon Neutralization published by Wenzhou University and John Wiley & Sons Australia, Ltd.

Original language	English
Article number	e70042
Number of pages	10
Journal	Carbon Neutralization
Volume	4
Issue number	5
Online published	25 Aug 2025
DOIs	https://doi.org/10.1002/cnl2.70042
Publication status	Published - Sept 2025

Funding

This work was supported by the National Natural Science Foundation of China (No. 62305015 and No. 22005013). The authors acknowledge the facilities and the scientific and technical assistance of the Analysis & Testing Center, Beihang University.

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

SDG 7 Affordable and Clean Energy

Research Keywords

buried interface
hysteresis
open-circuit voltage loss
perovskite solar cells
stability

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This full text is made available under CC-BY 4.0. https://creativecommons.org/licenses/by/4.0/

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@article{ff25426d57864a86aae1253713b53606,

title = "Buried Interface Modification for Reduced Open-Circuit Voltage Loss in Perovskite Solar Cells With Efficiency Exceeding 25.8\%",

abstract = "In n–i–p perovskite solar cells (PSCs), the buried interface of the perovskite layer is crucial for boosting both performance and stability. Here, multifunctional small molecule potassium trifluoromethanesulfonate (TFSK) is employed as an interlayer to efficiently bridge SnO2 and the buried perovskite film, simultaneously regulating interfacial energetics and morphology. This strategy provides several advantages: (1) TFSK passivates oxygen vacancy defects and surface hydroxyl groups on SnO2, while also improving energy level alignment; (2) TFSK modification induces a loose and porous morphology in PbI2, facilitating the diffusion of ammonium salts and promoting sufficient ionic reactions to high-quality FAPbI3 films; (3) TFSK interacts strongly with perovskite through Lewis acid–base interaction (between S=O groups and uncoordinated Pb²⁺) and hydrogen bonding (between F− and formamidinium cations), significantly suppressing non-radiative recombination. Consequently, the quality of both SnO2 and perovskite films is significantly improved, which greatly boosts the power conversion efficiency of small-size PSCs to 25.82\%, with a high open-circuit voltage of 1.19 V, a minimal voltage loss of 0.341 V, and negligible hysteresis. Moreover, the optimized SnO2/TFSK-based PSCs demonstrate improved storage, humidity, and thermal stability. {\textcopyright} 2025 The Author(s). Carbon Neutralization published by Wenzhou University and John Wiley \& Sons Australia, Ltd.",

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author = "Weiwei Sun and Kexiang Wang and Weifeng Liu and Yansheng Sun and Yukun Gao and Tingting You and Hong Lian and Xiaofeng Huang and Shuanglong Wang and Penggang Yin",

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AU - Sun, Weiwei

AU - Wang, Kexiang

AU - Liu, Weifeng

AU - Sun, Yansheng

AU - Gao, Yukun

AU - You, Tingting

AU - Lian, Hong

AU - Huang, Xiaofeng

AU - Wang, Shuanglong

AU - Yin, Penggang

PY - 2025/9

Y1 - 2025/9

N2 - In n–i–p perovskite solar cells (PSCs), the buried interface of the perovskite layer is crucial for boosting both performance and stability. Here, multifunctional small molecule potassium trifluoromethanesulfonate (TFSK) is employed as an interlayer to efficiently bridge SnO2 and the buried perovskite film, simultaneously regulating interfacial energetics and morphology. This strategy provides several advantages: (1) TFSK passivates oxygen vacancy defects and surface hydroxyl groups on SnO2, while also improving energy level alignment; (2) TFSK modification induces a loose and porous morphology in PbI2, facilitating the diffusion of ammonium salts and promoting sufficient ionic reactions to high-quality FAPbI3 films; (3) TFSK interacts strongly with perovskite through Lewis acid–base interaction (between S=O groups and uncoordinated Pb²⁺) and hydrogen bonding (between F− and formamidinium cations), significantly suppressing non-radiative recombination. Consequently, the quality of both SnO2 and perovskite films is significantly improved, which greatly boosts the power conversion efficiency of small-size PSCs to 25.82%, with a high open-circuit voltage of 1.19 V, a minimal voltage loss of 0.341 V, and negligible hysteresis. Moreover, the optimized SnO2/TFSK-based PSCs demonstrate improved storage, humidity, and thermal stability. © 2025 The Author(s). Carbon Neutralization published by Wenzhou University and John Wiley & Sons Australia, Ltd.

AB - In n–i–p perovskite solar cells (PSCs), the buried interface of the perovskite layer is crucial for boosting both performance and stability. Here, multifunctional small molecule potassium trifluoromethanesulfonate (TFSK) is employed as an interlayer to efficiently bridge SnO2 and the buried perovskite film, simultaneously regulating interfacial energetics and morphology. This strategy provides several advantages: (1) TFSK passivates oxygen vacancy defects and surface hydroxyl groups on SnO2, while also improving energy level alignment; (2) TFSK modification induces a loose and porous morphology in PbI2, facilitating the diffusion of ammonium salts and promoting sufficient ionic reactions to high-quality FAPbI3 films; (3) TFSK interacts strongly with perovskite through Lewis acid–base interaction (between S=O groups and uncoordinated Pb²⁺) and hydrogen bonding (between F− and formamidinium cations), significantly suppressing non-radiative recombination. Consequently, the quality of both SnO2 and perovskite films is significantly improved, which greatly boosts the power conversion efficiency of small-size PSCs to 25.82%, with a high open-circuit voltage of 1.19 V, a minimal voltage loss of 0.341 V, and negligible hysteresis. Moreover, the optimized SnO2/TFSK-based PSCs demonstrate improved storage, humidity, and thermal stability. © 2025 The Author(s). Carbon Neutralization published by Wenzhou University and John Wiley & Sons Australia, Ltd.

KW - buried interface

KW - hysteresis

KW - open-circuit voltage loss

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KW - stability

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DO - 10.1002/cnl2.70042

M3 - RGC 21 - Publication in refereed journal

SN - 2769-3333

VL - 4

JO - Carbon Neutralization

JF - Carbon Neutralization

IS - 5

M1 - e70042

ER -

Buried Interface Modification for Reduced Open-Circuit Voltage Loss in Perovskite Solar Cells With Efficiency Exceeding 25.8%

Abstract

Funding

UN SDGs

Research Keywords

Publisher's Copyright Statement

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