[TuA4] Organic Devices

5:45 PM - 6:00 PM JST(8:45 AM - 9:00 AM UTC)

[TuA4-04] Enhanced Photogating Effect in Organic Phototransistors via Electrospun Nanofiber-Induced Geometric Trap Engineering

〇YUTO Aoki¹, Takao Someya¹, Tomoyuki Yokota¹ (1. Graduate School of Engineering, The University of Tokyo (Japan))

Organic phototransistors (OPTs) offer high photoresponsivity through the photogating effect, but face an inherent trade-off between sensitivity and electrical stability due to trap-induced hysteresis. We propose a novel "geometric trap engineering" approach using electrospun polyurethane (PU) nanofibers to overcome this limitation. Nanomesh organic phototransistors (NMOPTs) with nanofiber-modified substrates demonstrated up to 9.6-fold enhancement in threshold voltage shift (ΔVth) under illumination compared to planar devices, while maintaining low hysteresis in the dark. Systematic studies revealed that thinner fibers (500 nm diameter) produced 7.1× larger photoresponse than controls. This geometry-based strategy provides a universal approach applicable to both small-molecule (DNTT) and polymer (C16-IDTBT) semiconductors.