Overcoming HTL Limitations: Interfacial Engineering and n-Doped HTL-Free Architectures in Perovskite Photodetectors

Kai-Chun Chang^a, Shu-Yu Yang^a, Chieh-Ting Lin^a

^aDepartment of Chemical Engineering, National Chung Hsing University, 145 Xingda Road, Taichung, 402-27, Taiwan

NIPHO26
Proceedings of International Conference on Perovskite Thin Film Photovoltaics and Perovskite Photonics and Optoelectronics (NIPHO26)

Pavia, Italy, 2026 June 8th - 9th

Organizers: Giulia Grancini and Robert Hoye

Oral, Kai-Chun Chang, presentation 009
Publication date: 22nd April 2026

Perovskite photodetectors show tremendous promise, yet traditional hole transport layers such as PEDOT:PSS often induce interfacial defects and energy mismatches that limit device performance¹. To overcome these HTL-related bottlenecks, this study proposes a systematic device engineering approach. First, we demonstrate that de-doping PEDOT:PSS using DBU effectively mitigates interfacial issues and enhances initial device performance². To fundamentally eliminate HTL-induced instability, we further develop an HTL-free architecture based on MAPbI₃. Since the direct removal of the HTL compromises the intrinsic electron-blocking capability, we introduce an n-type doping strategy into the perovskite layer. This n-doping effectively induces favorable interfacial band bending, restoring charge selectivity, suppressing dark current³, and significantly boosting the performance of HTL-free devices. Finally, to extend the detection range to the near-infrared region, we implement this "HTL-free and n-doped" strategy in narrow-bandgap tin-lead perovskites. The optimized Sn-Pb photodetectors demonstrate a remarkably suppressed dark current and an outstanding ON/OFF ratio, achieving superior NIR sensing capabilities⁴. This work provides a robust pathway for designing high-performance perovskite photodetectors for NIR detection.

References:

[1] R. Wang, M. Mujahid, Y. Duan, Z. K. Wang, J. Xue and Y. Yang, Adv. Funct. Mater., 2019, 29, 1808843.

[2] Z. E. Shi, H. J. Hsieh, Y. Y. Hsu, H. W. Lin, B. H. Jiang, C. T. Lin and C. P. Chen, Adv. Opt. Mater., 2025, 13, e01522.

[3] H. Chen, Y. Zhan, G. Xu, W. Chen, S. Wang, M. Zhang, Y. Li and Y. Li, Adv. Funct. Mater., 2020, 30, 2001788.

[4] H. Li, Y. Gao, X. Hong, K. Ke, Z. Ye, S. Zhang, K. Shi, Z. Peng, H. Yan, M. C. Tang, Y. Yao, B. Z. Tang, G. Wei and F. Kang, InfoMat, 2025, 7, e12615.

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