The sensitivity of cathodic photoelectrochemical (PEC) biosensor is mainly limited by the weak photocurrent response of p-type semiconductors due to the intrinsic weak hole conduction and severe charge recombination. Herein, we developed an antenna-like strategy that can amplify 10-fold of the cathodic photocurrent without using of p-type semiconductor. Specifically, poly (3,4-ethyl-enedioxythiophene) (PEDOT) was used as photocathode to improve the migration of photo-generated electrons (e⁻) from the n-type S doped-Bi₂WO₆ (Bi₂WO_6-xS_x) photoanode through the external circuit and therefore an amplified cathodic photocurrent can be obtained toward such an antenna-like strategy. We further demonstrated that the antenna-like effect is originated from the super electrical conductivity of PEDOT photocathode and the facilitated charge separation of Bi₂WO_6-xS_x photoanode by S doping. As a proof of concept, a self-powered dual-photoelectrode cathodic PEC biosensor driven by visible light was fabricated for microRNA-141 detection. Importantly, the biological recognition occurred at the photocathode could advance the anti-interference capability of the biosensor and show outstanding performance for microRNA-141 detection with a low limit of detection (LOD) of 0.3 fM. The antenna-like strategy offers a new method to amplify the cathodic photocurrent for sensitively PEC analysis.

由于固有的弱空穴传导和严重的电荷重组，阴极光电化学（PEC）生物传感器的灵敏度主要受到 p 型半导体的弱光电流响应的限制。在这里，我们开发了一种类似天线的策略，可以在不使用 p 型半导体的情况下将阴极光电流放大 10 倍。具体来说，聚（3,4-亚乙基二氧噻吩）（PEDOT）被用作光电阴极，以改善光生电子（e ^-）从n型S掺杂的Bi ₂ WO ₆（Bi ₂ WO _{6- x} S _x）通过外部电路的光阳极，因此可以通过这种类似天线的策略获得放大的阴极光电流。我们进一步证明了类天线效应源于PEDOT光电阴极的超导电性和Bi ₂ WO _{6- x} S _{x的促进电荷分离。}S掺杂的光阳极。作为概念验证，制造了一种由可见光驱动的自供电双光电极阴极 PEC 生物传感器，用于检测 microRNA-141。重要的是，在光电阴极上发生的生物识别可以提高生物传感器的抗干扰能力，并在检测下限 (LOD) 为 0.3 fM 的情况下表现出出色的 microRNA-141 检测性能。类似天线的策略为放大阴极光电流以进行灵敏的 PEC 分析提供了一种新方法。