Near-Infrared-Driven Multiplexed, Self-Powered Photoelectrochemical Sensor for Portable and Reliable Detection of...

The development of near-infrared (NIR)-driven photoelectrochemical (PEC) sensors for on-site, multianalyte detection remains challenging owing to the limited NIR responsiveness of photoactive materials and the reliance on complex, externally powered conventional PEC systems. Herein, we report a fully integrated, self-powered multiplexed PEC sensing chip for the simultaneous detection of three steroid estrogens, namely, 17β-estradiol (17β-E2), diethylstilbestrol (DES), and ethinylestradiol (EE2) based on enhanced photoelectric performance of ytterbium (Yb)-doped Bi₂S₃ in the NIR region. The engineered NIR-responsive Yb-Bi₂S₃ photoanode is then coupled with a Prussian blue cathode to construct a spontaneously operating PEC cell, enabling self-powered sensing without an external power source. A spatially resolved sensing architecture is further designed, in which three independent photoanode regions are functionalized with distinct aptamers, while an additional unmodified region serves as a reference channel. This self-calibration strategy enables normalization of photocurrent signals against the reference, effectively minimizing fluctuations caused by variations in light intensity and environmental conditions and thereby improving detection accuracy and reproducibility. Equipped with a portable Bluetooth ammeter for smartphone readout, the sensor achieves low detection limits of 1.71 × 10^-3, 1.50 × 10^-3, and 1.20 × 10^-2 nM for 17β-E2, DES, and EE2, respectively. This work presents a versatile and field-deployable platform for on-site, multiplexed detection in environmental and food safety monitoring.