Optically controllable dual-gate organic transistor produced via phase separation between polymer semiconductor and photochromic spiropyran molecules

Arylazopyrazole-modulated stable dual-mode phototransistors

High-performance organic devices with dynamic and stable modulation are essential for building devices adaptable to the environment. However, the existing reported devices incorporating light-activated units exhibit either limited device stability or subpar optoelectronic properties. Here, we synthesize a new optically tunable polymer dielectric functionalized with photochromic arylazopyrazole units with a cis-isomer half-life of as long as 90 days. On this basis, stable dual-mode organic transistors that can be reversibly modulated are successfully fabricated. The trans-state devices exhibit high carrier mobility reaching 7.4 square centimeters per volt per second and excellent optical figures of merit, whereas the cis-state devices demonstrate stable but starkly different optoelectronic performance. Furthermore, optical image sensors are prepared with regulatable nonvolatile memories from 36 hours (cis state) to 108 hours (trans state). The achievement of dynamic light modulation shows remarkable prospects for the intelligent application of organic optoelectronic devices.

Interface Engineering in Organic Field-Effect Transistors: Principles, Applications, and Perspectives

Heterogeneous interfaces that are ubiquitous in optoelectronic devices play a key role in the device performance and have led to the prosperity of today's microelectronics. Interface engineering provides an effective and promising approach to enhancing the device performance of organic field-effect transistors (OFETs) and even developing new functions. In fact, researchers from different disciplines have devoted considerable attention to this concept, which has started to evolve from simple improvement of the device performance to sophisticated construction of novel functionalities, indicating great potential for further applications in broad areas ranging from integrated circuits and energy conversion to catalysis and chemical/biological sensors. In this review article, we provide a timely and comprehensive overview of current efficient approaches developed for building various delicate functional interfaces in OFETs, including interfaces within the semiconductor layers, semiconductor/electrode interfaces, semiconductor/dielectric interfaces, and semiconductor/environment interfaces. We also highlight the major contributions and new concepts of integrating molecular functionalities into electrical circuits, which have been neglected in most previous reviews. This review will provide a fundamental understanding of the interplay between the molecular structure, assembly, and emergent functions at the molecular level and consequently offer novel insights into designing a new generation of multifunctional integrated circuits and sensors toward practical applications.

Systematic variation of thiophene substituents in photochromic spiropyrans

A new synthetic method was developed to incorporate spiropyran into thiophene based materials via a conjugated pathway. As the number of thiophene units increased, the thermal decay rate of the reverse reaction decreased in methanol, thus increasing the half-life of merocyanine.

Development of molecular photoswitch with very fast photoresponse based on asymmetrical bis-azospiropyran

To study the effects of an extended bis-azo conjugated bridge with two different photochemical functions on a molecule in photochromic responses, a novel asymmetrical bifunctional bis-azo spiropyran photochromic dye was designed and synthesized. The obtained photoresponses were compared with symmetrical bifunctional bis-azo spiropyran analogues, and relative mono-azo and simple spiropyrans. Colourimetric behaviour, luminescence, and switching kinetics of all the dyes were studied. The largest molar absorption coefficient in merocyanine form, quickest response to light, and highest fluorescence quantum yield of the spiropyran form with a superior ratio of emission intensities of spiropyran to merocyanine form were achieved for the asymmetric bis-azospiropyran. Solvatochromic effect was studied to observe the solvent effects on non-irradiation colouration of the photochromic dyes. Furthermore, The molecular energy levels for optimized geometries of the synthesized bis-azospiropyrans and their probable photochemical products were obtained at the B3LYP/6-31G(d) level of theory.