Weak Near‐Infrared Light Visualization Enabled by Smart Multifunctional Optoelectronics
Pengqing Bi, Jianqiu Wang, Zhihao Chen, Zelong Li, Cheng Tan, Jiawei Qiao, Jiangbo Dai, Tao Zhang, Jiajia Gao, Wei Peng Goh, Chengkun Lyu, Changyun Jiang, Xiaotao Hao, Jianhui Hou, Le Yang
Abstract
Abstract Visualizing weak NIR light is critical for sensing, imaging, and communication, but remains challenging due to inefficient detection and upconversion (UC) mechanisms. A smart NIR‐to‐visible photon‐UC organic optoelectronic device is reported that integrates photodetection, light‐emitting diode (LED), and photovoltaic capabilities to enable clear visualization of weak NIR light. The programmable device has continuous photodetection monitoring of the incident NIR intensity. When the incident intensity falls below a preset threshold, the LED function is automatically triggered to compensate for the UC emission, amplifying the visualization. The smart multifunctional device uses a carefully designed ternary bulk heterojunction sensitizer doped with rubrene:DBP as the emitter. It demonstrates high UC efficiency (>1.5%) for upconversion from 808 to 608 nm, allowing NIR visualization without external power under strong illumination. It also shows excellent NIR photodetection with photoresponsivity of 0.35 A W −1 at 800 nm and specific detectivity reaching 10¹ 2 –10¹ 3 Jones, enabling sensitive detection under low‐light conditions. It also exhibits a low turn‐on voltage (0.9 V) and luminance exceeding 1200 cd m − 2 at 5 V, ensuring energy‐efficient light compensation. Furthermore, it achieves >10% power conversion efficiency, enabling sustainable self‐powered operation. This multifunctional, high‐performance system offers great potential in sensing, energy harvesting, and display technologies.