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

Abstract

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 cm 2 V À 1 s À 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 p-p 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.

Structure, transport and photoconductance of PbS quantum dot monolayers functionalized with a copper phthalocyanine derivative

“…[22] Such a device works similarly to an FET but instead of a gate voltage, light illumination is used to modulate the current flow. [23] Fig. 4 displays photocurrent measurements performed on PbS-Cu-4APc thin films with a stagescanning confocal microscope equipped with a 633 nm laser (for more details see the SI unit).…”

Electronic Properties of Optically Switchable Photochromic Diarylethene Molecules at the Interface with Organic Semiconductors

“…[4][5][6][7] Switching between the two isomers fundamentally changes the electronic properties of the molecules, e.g., the optical gap, molecular dipole moment, molecular electron affinity, and ionization energy. [8][9][10][11][12] . Using PCOMs in blends with organic semiconductors or as photo-addressable interlayer between an organic semiconductor and an electrode, the photo-induced switching can tune charge transport as well as charge injection (extraction) properties in photoswitchable devices.…”

“…[10] It was reported that this change in IE can be used to alter the current through the channel of organic field effect transistors (OFET) where DAE molecules were blended into the polymeric semiconductor poly(hexylthiophene) (P3HT). [12,13] Nevertheless, the energy level alignment (ELA) at the electrode/DAE as well as the organic semiconductor/DAE interfaces is not comprehensively understood. Particularly with respect to metal electrodes, the energy position of DAE frontier levels is yet unknown, and even the ability to photo-switch the molecules in proximity to the metal can questioned due to dipole selection rules.…”

Optical properties of gold nanoparticles decorated with furan-based diarylethene photochromic molecules

“…There is a growing interest toward molecular switches that can be reversely triggered between two well-defined forms by external optical and/or electrical stimuli due to their potential use as ultracompact 3D data storage [1][2] , heavy metal sensors [3][4][5] , elements of nano-scaled molecular-based flexible devices [6][7] and molecular machines [8][9] . To be implemented in a real device, photoresponsive organic molecules have to display: long-term thermal stability, good fatigue resistance, highly sensitive response to light irradiation, non-destructive readout capability and small structural changes during switching.…”