Simultaneously Enhancing Charge Transport and Analyte Accessibility in Poly(3-hexylthiophene) Transistors via Highly π-π Stacking Nanowire Network for Ammonia Sensing

Abstract

Organic thin-film transistors (OTFTs) hold immense potential for ultrasensitive gas detection; however, their performance is fundamentally constrained by the trade-off between carrier mobility and analyte permeability. Herein, we resolve this dichotomy by engineering a long-range ordered P3HT nanowire percolation network via a kinetically controlled solvent-concentration-temperature ternary modulation strategy. This approach effectively enhances nanowire network continuity, thereby enabling efficient charge transport while preserving analyte-accessible diffusion pathways. Consequently, the optimized device achieves a six-fold enhancement in mobility and an exceptional ammonia (NH3) detection limit of 238 ppb, attributed to the unimpeded diffusion of analytes to the buried channel interface. Furthermore, to transcend the intrinsic non-linearity of physical adsorption kinetics, we integrate a gradient boosting regression algorithm, creating a "sensor-algorithm" initial proof-of-concept that enables precise, linearized quantitative analysis. This work provides a fundamental design principle for structuring soft electronic materials and demonstrates a versatile platform for low-power, intelligent environmental and health sensing applications.