CPOS Seminar: "Optimized Stamping Transfer Process for Efficient Organic Photodetectors with Enhanced Operational Stability"
Speaker: Woongsik Jang, Postdoctoral Researcher
School of Integrative Engineering, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul 06974, Republic of Korea / Nguyen Group, Center for Polymers and Organic Solids, UC Santa Barbara
The stamping transfer process has gained significant attention for large-scale roll-to-roll fabrication due to its process separability and process design flexibility. In this study, we report on a thermodynamically engineered transfer strategy that ensures residue-free printing of organic layers. By predicting the wetting coefficients and employing high-surface-energy polyurethane acrylate molds, we achieved systematic control over interfacial adhesion. An important finding in this work is the quantitative analysis of energy release rates as a function of temperature-dependent interfacial energy. This mechanical insight enabled the sequential integration of multiple-active layer design consisting of a single acceptor layer and a bulk-heterojunction layer (A/BHJ structure), which is fundamentally challenging to achieve via conventional solution processing. Unlike spin-coating, our dry-transfer approach preserves pristine interfacial integrity and enhances morphological stabilization. Compared to conventional spin coating, which suffers from interfacial degradation due to solution penetration, the transfer-printed organic photodetectors (OPDs) demonstrated superior morphology stabilization and interfacial integrity. Furthermore, the A/BHJ OPD achieved high performance, including excellent detectivity, reduced dark current, and rapid response times, driven by high hole injection barriers and suppressed trap sites. Finally, we demonstrated efficient wireless data communication using the OPDs, proving that optimized adhesion-controlled transfer processes can lead to highly durable and functional OPDs.
