Nanoscale Engineering of Ladder-Like Polysilsesquioxane Dielectric Surfaces Enables High-Performance Flexible Electronics

Achieving high-performance flexible organic thin-film transistors (OTFTs) operating at low voltages is vital for next-generation electronics. Here, we report a novel ladder-like polysilsesquioxane (LPSQ) dielectric with nanoscale functionalities (long alkyl chains and epoxy groups) that simultaneously enhance organic semiconductor (OSC) self-assembly and dielectric performance. Alkyl chains promote chain-on crystallization of C10-DNTT, while epoxy groups boost dielectric polarization and enable UV photopatterning. This yields an ultralow interface trap density of 6.00 × 10¹¹ cm^-2 and record-high hole mobility of 15.55 cm²/V·s at 5 V. The resulting OTFTs show excellent stability (threshold shift < 1 V over 200 min) and robust flexibility on PET substrates. Moreover, leveraging the dielectric's patternability, fully solution-processed flexible logic circuits (inverters and NAND/NOR gates) with voltage gains of up to 37.2 at 5 V are demonstrated. This work provides a molecular design strategy for high-k LPSQ dielectrics toward practical low-voltage flexible electronics.