All‐Visible Light‐Switchable Thin‐Film Transistor

Abstract Stimuli‐responsive organic thin‐film transistors (TFTs), such as light‐switchable TFTs, are key components for multifunctional optoelectronics beyond Moore. However, the modulation of the light‐switchable TFTs output developed so far requires the use of ultraviolet (UV) light, despite the latter triggers photooxidation and degradation of the molecular materials and hybrids thereof. Herein, an all‐visible light‐switchable TFT is reported whose current output can be reversibly interconverted between two different states by non‐coherent and low‐power (<1 mW cm⁻²) visible light. The light‐sensitive material is assembled by blending CdS quantum dots (QDs) coated by photochromic diarylethene (DAE) molecules with a semiconducting p‐type poly[2,5‐(2‐octyldodecyl)‐3,6‐diketopyrrolopyrrole‐alt‐5,5‐(2,5‐di(thien‐2‐yl)thieno[3,2‐b]thiophene)] (DPP‐DTT). For the first time, triplet energy transfer (TET) at the organic‐inorganic interface between photochromic molecules and QDs is exploited to drive light‐switchable TFTs devices, enabling DAEs reversible photoisomerization when exposed to 405 nm and 515 nm visible light. Significantly, the conversion efficiency of DAEs via all‐visible‐light switching is comparable to that achieved under UV light irradiation, while the light switching fatigue resistance of the devices displayed a radical improvement. The work provides a new pathway to realize all‐visible‐light activated devices for future design of advanced digital optoelectronics in the context of next‐generation data storage technologies and neuromorphic computing.