The authors define thick-film OPVs as greater than 300 nm and describe advantages for scalable manufacturing, stronger near-infrared absorption, and improved mechanical robustness for flexible devices. They also chart the drawbacks: increased exciton recombination, unbalanced charge transport, and morphology control challenges across the film thickness.
Solutions are organized along the photovoltaic process. For exciton management, the review highlights molecular design of non-fullerene acceptors, judicious fluorinated additives, and tighter control of molecular packing to extend diffusion and aid dissociation in thicker layers.
For carrier transport, it details tactics to enhance and balance electron and hole mobilities, including promoting molecular planarity and crystallinity and engineering vertical phase separation that guides charges efficiently to electrodes without penalizing optical absorption.
To suppress recombination and aid extraction, the authors discuss side-chain engineering, solvent additive selection, and tuning polymer molecular weight to limit trap states and foster percolated pathways. Collectively, these approaches target thickness-tolerant architectures.
Reported outcomes include thick-film devices surpassing 19 percent efficiency, with some systems maintaining strong performance above 500 nm active layers. Stability strategies such as entropy-driven stabilization and crystallization-sequence control preserve 80-90 percent of initial efficiency after 1,000 hours of thermal aging.
Cost considerations feature low-cost polymer donors such as PTQ10 and TVT-based materials, alongside reduced material waste when processing thicker layers at scale. The piece also surveys machine learning tools that accelerate materials screening and device optimization for thickness-agnostic OPVs.
Published in Nano-Micro Letters on 23 Jul 2025, the review provides practical guidelines that connect lab breakthroughs to industrial fabrication, spanning molecular engineering through device-stack design and reliability testing.