Flexible optoelectronic sensors: status and prospects

Different from conventional circuits made of bulky semiconductors, flexible electronics bring mechanical flexibility and remove form factor constraints from highly functional systems, which stimulates innovative applications. This leads to rapid progress in relevant fields such as displays, energy, robotics, biomedicine, etc., where flexible sensors play critical roles. Among the different types of sensors, optoelectronic sensors are relatively non-invasive, of high-speed nature, diverse, etc., and hence the advances in flexible photodetectors and systems are of importance and broad interest. However, at the device/system level, the mechanical, optical, and electrical functionalities must be carefully balanced, and thus a comprehensive and critical overview/discussion on the state-of-the-art materials, challenges, and prospects is required. In this review, we discuss, from both fundamental and application points of view, the principles of material selection, device design, and system integration within a flexible platform towards advanced optoelectronic sensing applications such as flexible imaging and biomimic vision systems, human-machine interaction, healthcare and biomedicine.