All-Visible Light-Switchable Thin-Film Transistor

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.