Grain Boundary Pinning Strategy for Enhanced Aggregate State in Organic Semiconductor Thin Films Toward Wide-Temperature-Range and Long-Term Stable Gas Sensors

초록

Flexible gas sensors based on organic semiconductors (OSCs) show great promise for diverse applications, yet their practical application is hindered by the limited operational and shelf stability of OSC-based gas sensors over a wide temperature range. Herein, we developed a universal grain boundary pinning strategy to cooperatively optimize the aggregate state stability, sensitivity, and selectivity of the ultrathin OSC film. By incorporating multi-functional Au nanoclusters into the OSC layer, the thermally activated molecular motion and grain boundary migration can be inhibited by the cooperative effect of strain-balancing and dipole-pi interactions. Consequently, the NH3 sensor based on 5 nm ultrathin film exhibits record stability over an extended shelf period (tested shelf life of one-year, theoretical shelf life of 14.8 years) and across a wide temperature range (RT-100 degrees C on polymer substrate, RT-180 degrees C on SiO2 substrate). The grain boundary pinning strategy is demonstrated to be universal across multiple OSC systems, underscoring its potential to enable robust, high-performance flexible gas sensors for widespread commercialization.

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