Screen-printing Bi2S3 nanowires on silk fabrics for a flexible optical switch

The development of textile-based wearable devices has been a hot research topic in recent years. However, a fabric-supported optical switch has never been reported. Herein, a pair of interdigital silver electrodes and hydrothermally synthesized Bi2S3 nanowires (NWs) were screen-printed successively onto silk fabric to construct a silk fabric-based flexible optical switch. The device showed irradiation power-dependent light-on currents and was able to respond to blue, green and red light. A fast response/recovery time of less than 2 ms could be achieved. After 120 cycles of distortion or bending, the light-on current remained as high as >85%. Bi2S3 NW films with different patterns could be printed on top of the devices without significantly affecting their performance. It was also demonstrated that the system could be utilized to trigger the rotation of an electrical fan. This work may provide a facile approach for the preparation of a silk fabric-based optical switch for wearable electronics.