Long-Term Stable Transferred Organic Photoactive Layer-Based Photodiode with Controlled Wetting through Interface Stabilization.

The stamping transfer process, which provides a precise patterning of the target material without the limitation of an underlying layer, has attracted significant attention for large-scale roll-to-roll fabrication. Despite the need to minimize the peeling energy, expressed as the sum of adhesion energies, for a simple transfer process, many studies have not considered this effect. In this study, we introduced a wetting coefficient related with adhesions between polymers for the transfer design of organic photosensitive materials. We observed a difference in adhesion between polymer blends depending on the surface energy of the mold. We designed high-surface-energy polyurethane acrylate to enable a residue-free transfer process. The transfer process significantly contributed to the device stability through changes in dark currents, photocurrents, responsivity, and detectivity over time, compared to spin coating. In particular, the detectivity was maintained over 95% after 360 h, and no burn-in loss of internal resistance was observed in the device with a transferred active layer. X-ray photoelectron spectroscopy showed that a large interfacial change between poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) and poly(4,8-bis[(2-ethylhexyl)oxy]benzo[1,2- b:4,5- b']dithiophene-2,6-diyl- alt-3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4- b]thiophene-4,6-diyl):[6,6] phenyl C71 butyric acid methyl ester obtained through spin coating occurred owing to solution penetration, whereas the transfer process provided a constant interface owing to morphology stabilization. Therefore, the transfer process with optimized adhesion properties can improve the device operation durability without burn-in loss, enabling a cost-effective fabrication of organic optoelectronic devices.