Enhancing thermal stability of solution-processed small molecule semiconductor thin films using a flexible linker approach

TL;DR

This paper introduces a flexible linker additive that enhances the thermal stability of solution-processed small molecule semiconductor thin films, significantly improving device longevity without compromising efficiency.

Contribution

A novel additive design employing flexible linkers to stabilize small molecule active layers in solution-processed organic electronic devices.

Findings

Additive inhibits active layer degradation under thermal stress.

Formation of more robust thin film microstructure with additive.

Applicable to various small molecule-based devices.

Abstract

Solution-processed organic photovoltaics (OPV) have recently reached the target 10% power conversion efficiency expected to signal their viable commercialization as an inexpensive and scalable energy conversion technology. However, obtaining devices with suitable long-term stability remains an unsolved challenge. Here we present a new strategy to improve the thermal stability of small-molecule-based bulk-heterojunction OPVs by including a custom additive specifically designed to interact with the device active layer components. Our results indicate that active layer degradation under continuous thermal stress can be inhibited due to the formation of more robust thin film microstructure with the additive present. Since our additive employs the identical semiconductor core used in the active layer, but linked by aliphatic chains into a flexible polymer, this straightforward strategy can reasonably be applied to stabilize a wide variety of semiconducting small molecules in solution-processed molecular OPVs, transistors and light emitting diodes.