Polymeric gel-mediated grain boundary self-healing for the fabrication of high-performance and durable organic thin-film transistors

Electrical degradation caused by grain boundaries in organic semiconductor (OSC) films is a prevalent issue that limits the large-area applications of organic electronics. Here, we report a polymer gel composed of polyethyleneimine and polydimethylsiloxane, which enables a of grain-boundary self-healing (GBSH) treatment within as-deposited OSC films by providing ionic conductivity across grain boundaries. The gel-based GBSH treatment demonstrates universal efficacy across a variety of OSC-based films for enhancing the operational performance of OTFTs. Typically, it enhances the field-effect mobilities of p -type rubrene-based and n -type PTCDI-C8-based OTFTs by 43 times and 25 times, respectively, while increasing their on/off ratio by 14.2-fold and 7.9-fold, respectively. Moreover, the GBSH treatment enables the enhanced stability of OTFTs under ambient conditions. The field-effect mobility of rubrene-based OTFTs, which decreased by 64 % within 11 days, was reduced to only a 29 % decrease over 90 days following the GBSH treatment. Additionally, the GBSH treatment mitigates the adverse impact of grain boundary anisotropy on device uniformity. The coefficient of variation for the field-effect mobility of rubrene-based OTFT arrays was reduced from 95 % to 13 % following the GBSH treatment, satisfying the industry standard for silicon-based devices. Moreover, the GBSH treatment is a post-fabrication process that is easy to implement. By conveniently depositing the gel onto OSC films via either spin-coating or drop-casting, it enables the in-situ repair of damaged grain boundaries within operational devices, thereby restoring device performance beyond that of freshly fabricated devices. The GBSH strategy represents a significant advancement toward high-performance organic electronics tailored for large-area applications.