Marangoni Flow Driven via Hole Structure of Soluble Acene–Polymer Blends for Selective Nitrogen Dioxide Sensing

Abstract

The correlations between semiconductor type and gas sensing properties in soluble acene/polymer blends have not yet been examined. Here, the phase separation mechanism in pseudo‐liquid phase blend film is investigated and an unusual solid‐state morphology that is effective for amperometric gas sensing performance is demonstrated. In 6,13‐bis(triisopropylsilylethynyl) pentacene (TIPS–pentacene)/poly(fluorine‐co‐triarylamine) (PTAA) blend, two phases are uniformly mixed, without being completely phase‐separated due to the similar solubility and surface tension. On the other hand, in 2,8‐difluoro‐5,11‐bis(triethylsilylethynyl) anthradithiophene (diF–TES ADT)/PTAA blend, the diF−TES ADT molecules are segregated both at the air–film, and film–substrate interfaces, and subsequently crystallized with a high degree of crystal perfection. In the meanwhile, Marangoni‐flow induces crater‐like via hole structure of PTAA at the middle layer. In situ measurement of (ultraviolet–visible) UV–vis absorption spectra and computational calculation reveal kinetics of liquid–solid–crystal transition in relation to the functional groups of soluble acene. Interestingly, flow driven hole structure of PTAA in diF–TES ADT/PTAA blend film allows the target NO2 gas to selectively penetrate the channel region, thereby enhancing sensitivity toward NO2, while decreasing affinity with other gases. The results provide protocols for fabricating highlperformance field‐effect transistors and gas sensors in a blending system.

An Organic Optoelectronic Synapse with Multilevel Memory Enabled by Gate Modulation

“…In this work, we report an optically switchable organic synapse based on a simple OFET structure with 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-Pen), a widely explored p-type semiconductor, , as the channel material (Figure a). TIPS-Pen molecules exhibit a two-dimensional “brick-wall” packing motif in the solid state, which facilitates efficient charge carrier transport.…”

Optimization of Gas-Sensing Properties in Poly(triarylamine) Field-Effect Transistors by Device and Interface Engineering

“…From the literature, it has been found that the amorphous polymer poly(triarylamine) (PTAA) can serve as an excellent active layer for OFET-based NO 2 sensors [ 14 , 15 ]. PTAA possesses the highest occupied molecular orbital (HOMO) level of −5.14 eV [ 16 ], enabling stable operation in ambient conditions.…”

“…However, the precise mechanism of gas detection requires further study, including investigations into gas dynamics (such as diffusion) and device physics. Continued research efforts are aimed at optimizing PTAA-based sensors, which involve the development of novel device structures, surface functionalization techniques, and integration with other materials or technologies to enhance overall sensor performance [ 11 , 14 , 17 , 18 ].…”