Simulation-Guided Design of High-Performance, Low-Cost Organic Transistors

Organic semiconductors could enable new applications like flexible displays, transparent solar cells and biocompatible medical devices. However, their widespread adoption is hindered by performance limitations stemming from thin-film imperfections and inefficient charge injection. The vast design space, encompassing a myriad of materials and device geometries, presents a significant challenge to device optimization. To address this challenge, we employed large-scale simulations to identify design windows where device performance is less susceptible to variations in hard-to-control parameters. This approach, coupled with experimental validation, allowed us to systematically investigate the interplay between injection barriers, trap densities, dielectric capacitance, and device architecture in organic field-effect transistors (OFETs). Our methodology yielded two key breakthroughs. Firstly, we significantly broadened the selection of suitable electrode materials by identifying geometries that mitigate the detrimental impact of injection barriers. This facilitated the fabrication of fully-printed, high-performance all-organic OFETs on flexible substrates, achieving mobilities exceeding 5 cm²/Vs without requiring laborious optimization. Second, through device simulations, we identified geometries that enable the use of semiconductors with higher impurity concentrations. By understanding how dielectric capacitance modulates trap state filling, we demonstrated that a 2% impurity could be introduced without compromising performance, provided the optimal OFET geometry is employed. These results provide a pathway to accelerate device optimization by transitioning from empirical trial-and-error approaches to a design paradigm that is more resilient to non-ideal charge injection and material defects.