Multifunctional l-tryptophan derivative induced surface passivation for lateral perovskite photodetectors

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2023-03, Vol.459, p.141602, Article 141602
• Main Authors: Wang, Yadong, Niu, Guosheng, Cao, Xiaofei, Yang, Zhichao, Dong, Yuan, Feng, Guitao, Liu, Yingliang, Wang, Jizheng, Cao, Shaokui
• Format: Article
• Language: English
• Subjects: l-tryptophan ethyl ester hydrochloride; Perovskite photodetector; Stability; Surface passivation
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2023.141602

•A multifunctional molecule l-TEEH is used to treat the surface of perovskite film.•The l-TEEH passivates the uncoordinated ions and halide vacancies of perovskite film.•The optimized photodetector exhibits the improved photovoltaic performances.•The bilayer l-TEEH/perovskite device has the reliable imaging capability. Organic-inorganic hybrid perovskites have already been employed as promising light-sensitive materials for high-performance photodetectors (PDs) due to their intriguing optoelectronic features. Nonetheless, such perovskite-based PDs often suffer from low sensitivity, high dark current and inevitable degradation. In this work, a novel multifunctional molecule l-tryptophan ethyl ester hydrochloride (l-TEEH) was used to treat the surface defects of triple-cation mixed halide perovskite film. It is found that the modulator with multiple functional groups can effectively passivate the uncoordinated ions (Pb2+ and I-) and halide (I and Cl) vacancies of the perovskite film. Owing to the reduced defects, the dark current of the pristine perovskite PD significantly decreases from ∼ 10-9 A to ∼ 10-11 A after the l-TEEH treatment. Moreover, the perovskite PD with the l-TEEH treatment exhibits a large photoresponsivity (1.27 A/W) and an ultrahigh on/off ratio (∼9 × 103). More impressively, the optimized device shows excellent stability in air with a relative humidity of 40–50 %. Furthermore, the reliable imaging capability of perovskite device with the l-TEEH treatment is also successfully demonstrated.