Molecular Anchoring Strategies for Enhanced Thermal Stability in Organic Field-Effect Transistors

Thermally stable organic transistors are crucial for ensuring reliable performance in diverse applications, including high-temperature environments and thermally demanding electronic systems. However, developing thermally stable organic semiconductors with excellent charge transport capability remains a great challenge. Here, a thermally stable and high-performance organic semiconductor, [1]benzothieno[3,2-<i>b</i>][1]benzothiophene (BTBT) derivative BTBT-PO8OP, is designed by incorporating a phenyl-anchored unit in the side chain. The highly ordered molecular arrangements in the BTBT-PO8OP films promotes strong intermolecular π-π interactions and efficient charge transport, enabling BTBT-PO8OP-based organic transistors to achieve a high mobility of 2.68 cm² V^-1 s^-1 and remarkable performance uniformity. Under thermal stress, the anchor-shaped side chain restricts molecular curling and contraction, maintaining the structural integrity of the molecules. Even at 145 °C, the phenyl anchor structure in BTBT-PO8OP-based organic transistors effectively mitigates side-chain curling, preserving molecular order and effective charge transport property, leading to superior thermal stability compared to mainstream small molecular material C8-BTBT. This work presents a promising material for thermally stable and high-performance organic transistors and demonstrates the potential of anchor-structure strategies in addressing the challenges of developing thermally stable organic semiconductors toward transistor-based applications.