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Vol. 18 (2026)

Enhancing Ultraviolet Stability and Operational Durability of Perovskite Photodetectors by Incorporating Chlorine into Thermally-Switchable Tautomeric Passivators

https://doi.org/10.1007/s40820-025-02015-5
Yong Wang
Yunnan Key Laboratory for Micro/Nano Materials & Technology, School of Materials and Energy, Yunnan University, Kunming 650500, People’s Republic of China
Guangsheng Liu
Yunnan Key Laboratory for Micro/Nano Materials & Technology, School of Materials and Energy, Yunnan University, Kunming 650500, People’s Republic of China
Feng Lin
Yunnan Key Laboratory of Electromagnetic Materials and Devices, School of Materials and Energy, Yunnan University, Kunming 650091, People’s Republic of China
Yuqin Hu
Yunnan Key Laboratory for Micro/Nano Materials & Technology, School of Materials and Energy, Yunnan University, Kunming 650500, People’s Republic of China
Niu Lai
Yunnan Key Laboratory for Micro/Nano Materials & Technology, School of Materials and Energy, Yunnan University, Kunming 650500, People’s Republic of China
Junhong Lv
Yunnan Key Laboratory for Micro/Nano Materials & Technology, School of Materials and Energy, Yunnan University, Kunming 650500, People’s Republic of China
Shuming Ye
Yunnan Key Laboratory for Micro/Nano Materials & Technology, School of Materials and Energy, Yunnan University, Kunming 650500, People’s Republic of China
Jie Yang
Yunnan Key Laboratory for Micro/Nano Materials & Technology, School of Materials and Energy, Yunnan University, Kunming 650500, People’s Republic of China
Rongfei Wang
Yunnan Key Laboratory for Micro/Nano Materials & Technology, School of Materials and Energy, Yunnan University, Kunming 650500, People’s Republic of China
Feng Qiu
Yunnan Key Laboratory for Micro/Nano Materials & Technology, School of Materials and Energy, Yunnan University, Kunming 650500, People’s Republic of China
Yu Yang
Yunnan Key Laboratory for Micro/Nano Materials & Technology, School of Materials and Energy, Yunnan University, Kunming 650500, People’s Republic of China
Wenhua Zhang
Yunnan Key Laboratory of Electromagnetic Materials and Devices, School of Materials and Energy, Yunnan University, Kunming 650091, People’s Republic of China
Chong Wang
Yunnan Key Laboratory for Micro/Nano Materials & Technology, School of Materials and Energy, Yunnan University, Kunming 650500, People’s Republic of China

Corresponding Author: Chong Wang

cwang@ynu.edu.cn

Nano-Micro Letters, Vol. 18 (2026), Article Number: 178

Abstract

UV-absorbing additives have recently been demonstrated to be effective interfacial modifiers that simultaneously enhance the UV stability and crystallization of halide perovskite. However, the underlying mechanisms concerning UV absorption, defect passivation, and efficacy optimization of these additives remain unresolved. Herein, two UV tautomeric absorbers (UV320 and UV327) are selected as defect-passivators for perovskites. The keto–enol tautomeric evolution processes and corresponding defect passivation performance/mechanism of both the original molecules and their tautomers are thoroughly compared and elucidated through experimental characterizations and density functional theory calculations. The additional carbonyl (–C=O) groups generated through the keto–enol tautomeric process triggered by the Cl atom in UV327 ultimately provide superior chemical coordination and enhanced defect-passivation capability compared to the original counterparts. Moreover, the versatility of K-UV327 is further demonstrated by its optimization of SnO2 film quality, interfacial energy band alignment, charge extraction efficiency, and defect state suppression. The photodetector optimized by UV327’s tautomer achieves an ultralow dark current density of 3.22 × 10−10 A cm−2, an enhanced linear dynamic range of 94.14 dB, and a fast response time of 23.35/26.19 μs. Notably, unencapsulated devices maintain a stable response at 3900 Hz following 300 h exposure to 40% ± 5% relative humidity and 30 h UV irradiation.


Highlights:
1 The tautomeric UV absorbers (UV320/UV327) in perovskites reveal keto–enol tautomerism, generating extra –C=O groups to enhance defect passivation.
2 The Cl atom in UV327 drives tautomerism, providing superior –C=O coordination, which optimizes SnO2 energy bands/charge extraction, resulting in a dark current of 3.22 × 10−10 A cm−2 and a response time of 23.35/26.19 μs.
3 Unencapsulated devices maintained 3900 Hz response after 300 h humidity (40 ± 5% RH) and 30 h UV stress, with 94.14 dB linear dynamic range.

Keywords

Perovskite photodetector Tautomer passivator Surface defect passivation Ultraviolet absorbent
Wang, Yong, Guangsheng Liu, Feng Lin, Yuqin Hu, Niu Lai, Junhong Lv, Shuming Ye, Jie Yang, Rongfei Wang, Feng Qiu, Yu Yang, Wenhua Zhang, and Chong Wang. 2026. “Enhancing Ultraviolet Stability and Operational Durability of Perovskite Photodetectors by Incorporating Chlorine into Thermally-Switchable Tautomeric Passivators”. Nano-Micro Letters 18 (January):178. https://doi.org/10.1007/s40820-025-02015-5.
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