Progress of Proximity Sensors for Potential Applications in Electronic Skins

Recently, electronic skins and flexible wearable devices have been developed for widespread applications in medical monitoring, artificial intelligence, human–machine interaction, and artificial prosthetics. Flexible proximity sensors can accurately perceive external objects without contact, introducing a new way to achieve an ultrasensitive perception of objects. This article reviews the progress of flexible capacitive proximity sensors, flexible triboelectric proximity sensors, and flexible gate-enhanced proximity sensors, focusing on their applications in the electronic skin field. Herein, their working mechanism, materials, preparation methods, and research progress are discussed in detail. Finally, we summarize the future challenges in developing flexible proximity sensors.