Key Laboratory of Wide Band-Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi'an 710071, China.
Xi'an Mental Health Center, Xi'an 710061, China.
Anal Chem. 2023 May 16;95(19):7560-7568. doi: 10.1021/acs.analchem.3c00046. Epub 2023 May 3.
A semiconductor photoelectrochemical (PEC) aptamer sensor has been widely researched in recent years because of its broad application prospects. However, a universal PEC sensor has not been achieved, and its sensing mechanism based on a photogenerated carrier transfer process has yet to be elucidated. Herein, a novel hydrogen-treated TiO nanorod array one-dimensional (1D)/TiCO MXene two-dimensional (2D) (H-TiO/TiCO) PEC aptamer sensor is presented, which achieved a record detection range of 10-10 μg/L and a limit of detection (LOD) of 1 fg/L for microcystic toxins-LR detection. Besides, the PEC sensor can also test serotonin (5-HT), aflatoxin-B1, and prostate-specific antigen (PSA) with high performance by changing the aptamers, exhibiting favorable application universality. Furthermore, a new phenomenon of a switchable enhanced/suppressed photocurrent detection signal was discovered from H-TiO/TiCO PEC aptamer sensors through the variation of the length of the TiO nanorod. Meanwhile, it reveals that the steric hindrance effect determines the photogenerated hole transfer and depolarization processes, which is proposed for the first time as the predominant mechanism of the switchable enhanced/suppressed photocurrent signal for PEC sensors, giving possibilities to develop PEC sensors with higher efficiency.
近年来，半导体光电化学（PEC）适体传感器因其广泛的应用前景而受到广泛研究。然而，尚未实现通用的 PEC 传感器，其基于光生载流子转移过程的传感机制仍有待阐明。在此，提出了一种新型的氢处理 TiO 纳米棒阵列一维（1D）/TiCO MXene 二维（2D）（H-TiO/TiCO）PEC 适体传感器，该传感器在检测微囊藻毒素-LR 时实现了创纪录的检测范围 10-10μg/L 和检测限（LOD）为 1fg/L。此外，通过改变适体，该 PEC 传感器还可以测试血清素（5-HT）、黄曲霉毒素-B1 和前列腺特异性抗原（PSA），具有良好的应用通用性。此外，通过改变 TiO 纳米棒的长度，从 H-TiO/TiCO PEC 适体传感器中发现了一种开关式增强/抑制光电流检测信号的新现象。同时，首次提出空间位阻效应决定光生空穴转移和去极化过程，这被提议作为 PEC 传感器开关式增强/抑制光电流信号的主要机制，为开发更高效率的 PEC 传感器提供了可能性。
