Optically switchable transistors by simple incorporation of photochromic systems into small-molecule semiconducting matrices.

The fabrication of multifunctional high-performance organic thin-film transistors as key elements in future logic circuits is a major research challenge. Here we demonstrate that a photoresponsive bi-functional field-effect transistor with carrier mobilities exceeding 0.2 cm2 V−1 s−1 can be developed by incorporating photochromic molecules into an organic semiconductor matrix via a single-step solution processing deposition of a two components blend. Tuning the interactions between the photochromic diarylethene system and the organic semiconductor is achieved via ad-hoc side functionalization of the diarylethene. Thereby, a large-scale phase-segregation can be avoided and superior miscibility is provided, while retaining optimal π–π stacking to warrant efficient charge transport and to attenuate the effect of photoinduced switching on the extent of current modulation. This leads to enhanced electrical performance of transistors incorporating small conjugated molecules as compared with polymeric semiconductors. These findings are of interest for the development of high-performing optically gated electronic devices. Organic thin-film transistors can be photomodulated by incorporating photochromic molecules, but the state-of-the-art suffers from poor charge transport. Here, the authors improve charge mobility by three orders of magnitude by blending small conjugated molecules into diarylethene.