Light Intensity Switches Photocurrent Polarity via Surface States in Single-Component Semiconductors
- 1Southeast University
Abstract
Understanding and regulating photocurrent generation in semiconductors, particularly the control of polarity, is central to photoelectrochemical (PEC) system design. While engineered heterojunctions enable wavelength-dependent polarity switching, they require complex architectures. Light intensity, by contrast, is far more readily tuned but has long been limited to modulating photocurrent magnitude. Herein, we report that surface states, which participate in photoinduced carrier transfer, can mediate light-intensity-dependent photocurrent polarity reversal in single-component semiconductors of both n- and p-type (e.g., carbon nitride, CdTe quantum dots, and BiOI). Mechanism studies reveal that in the photocurrent switching potential (E ps ) region, where the built-in potential is attenuated, surface state occupation, dictated by illumination intensity, governs the direction of charge transfer. This surface-state-mediated mechanism establishes light intensity as an orthogonal dimension for adaptive photoresponsivity, bypassing the need for heterojunction engineering. As a proof of concept, a dopamine PEC biosensor built on this principle achieves exceptional selectivity without conventional biorecognition units, where photocurrent polarity itself serves as the recognition dimension.
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BibTeX
@misc{li2026light,
title = {{Light Intensity Switches Photocurrent Polarity via Surface States in Single-Component Semiconductors}},
author = {Wang Li and Kaiqing Wu and Hong Yang and Qiushi Ruan and Sicheng Liang and Kaiyuan Wang and Songqin Liu and Haibin Zhu and Yanfei Shen and Yuanjian Zhang},
howpublished = {ChemRxiv},
year = {2026},
month = oct,
doi = {10.26434/chemrxiv-2024-h0b3g/v4},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv-2024-h0b3g/v4},
note = {CC BY},
}
RIS
TY - UNPB
TI - Light Intensity Switches Photocurrent Polarity via Surface States in Single-Component Semiconductors
AU - Wang Li
AU - Kaiqing Wu
AU - Hong Yang
AU - Qiushi Ruan
AU - Sicheng Liang
AU - Kaiyuan Wang
AU - Songqin Liu
AU - Haibin Zhu
AU - Yanfei Shen
AU - Yuanjian Zhang
PY - 2026
DA - 2026/10/05
PB - ChemRxiv
DO - 10.26434/chemrxiv-2024-h0b3g/v4
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv-2024-h0b3g/v4
AB - Understanding and regulating photocurrent generation in semiconductors, particularly the control of polarity, is central to photoelectrochemical (PEC) system design. While engineered heterojunctions enable wavelength-dependent polarity switching, they require complex architectures. Light intensity, by contrast, is far more readily tuned but has long been limited to modulating photocurrent magnitude. Herein, we report that surface states, which participate in photoinduced carrier transfer, can mediate light-intensity-dependent photocurrent polarity reversal in single-component semiconductors of both n- and p-type (e.g., carbon nitride, CdTe quantum dots, and BiOI). Mechanism studies reveal that in the photocurrent switching potential (E ps ) region, where the built-in potential is attenuated, surface state occupation, dictated by illumination intensity, governs the direction of charge transfer. This surface-state-mediated mechanism establishes light intensity as an orthogonal dimension for adaptive photoresponsivity, bypassing the need for heterojunction engineering. As a proof of concept, a dopamine PEC biosensor built on this principle achieves exceptional selectivity without conventional biorecognition units, where photocurrent polarity itself serves as the recognition dimension.
ER -