Visible-blind UV monitoring with a photochromic charge trapping layer in organic field-effect transistors

An alternative strategy is proposed to achieve visible-blind ultraviolet (UV) monitoring. By introducing photochromic spiropyran (SP) molecules into the dielectric as the charge trapping layer, organic field-effect transistor (OFET) memories show a selective response to UV light and are inert to visible light. The photoisomerization of SP from the ring-close to ring-open states under UV illumination modifies its electronic structure, which facilitates electron trapping into the charge trapping layer and accordingly induces the memory effect. UV exposure recording can be realized by cumulative and nonvolatile electron trapping, enabling potential applications of OFET memories for UV monitoring in wearable electronics.