Perovskite Solar Cell‐Gated Organic Electrochemical Transistors for Flexible Photodetectors with Ultrahigh Sensitivity and Fast Response

Photodetectors (PDs) are the building block of various imaging and sensing applications. However, commercially available PDs based on crystalline inorganic semiconductors cannot meet the requirements of emerging wearable/implantable applications due to their rigidity and fragility, which creates the need for flexible devices. Here, a high‐performance flexible PD is presented by gating an organic electrochemical transistor (OECT) with a perovskite solar cell. Due to the ultrahigh transconductance of the OECT, the device demonstrates a high gain of ≈106, a fast response time of 67 µs and an ultrahigh detectivity of 6.7 × 1017 Jones to light signals under a low working voltage (≤0.6 V). Thanks to the ultrahigh sensitivity and fast response, the device can track photoplethysmogram signals and peripheral oxygen saturation under ambient light and even provide contactless remote sensing, offering a low‐power and convenient way for continuous vital signs monitoring. This work offers a novel strategy for realizing high‐performance flexible PDs that are promising for low‐power, user‐friendly and wearable optoelectronics.

光电探测器（PDs）是各种成像和传感应用的基石。然而，基于晶体无机半导体的市售光电探测器由于其刚性和易碎性无法满足新兴的可穿戴/可植入应用的要求，这就产生了对柔性器件的需求。在此，通过用钙钛矿太阳能电池对有机电化学晶体管（OECT）进行门控，展示了一种高性能的柔性光电探测器。由于OECT的超高跨导，该器件在低工作电压（≤0.6 V）下对光信号表现出约10⁶的高增益、67微秒的快速响应时间以及6.7×10¹⁷琼斯的超高探测率。由于超高的灵敏度和快速的响应，该器件可以在环境光下跟踪光电容积脉搏波信号和外周血氧饱和度，甚至提供非接触式遥感，为连续生命体征监测提供了一种低功耗且便捷的方式。这项工作为实现高性能柔性光电探测器提供了一种新策略，对低功耗、用户友好型和可穿戴光电子器件具有应用前景。