Mechanical Property Tunable P(LMA‐ <i>co</i> ‐EGDMA) Layer of Thin‐Film Encapsulation in Organic Solar Cell

Aiming to achieve in situ, compatible deposition of polymer films on the top electrode of organic solar cells (OSCs), a solvent-free polymerization system using lauryl methacrylate monomer is developed. The in situ polymerization at room temperature is initiated by UV light, and the effects of different cross-linking monomers and organic elastomer components ratios are systematically studied with device performance evaluation. Laser beam-induced current imaging is used to characterize the current distribution of the device when the polymer film is deposited on the top electrode. The relationship between the mechanical stress release process of the polymer film and the performance changes of the device during long-term storage is established, allowing for the evaluation and selection of the optimal polymerization system components at the device performance level. In this part of the study, higher cross-linking monomer content leads to more significant damage to the device electrodes due to film volume shrinkage, while organic elastomer materials effectively alleviate the mechanical stress caused by film shrinkage during polymerization. Combined with PHPS-derived inorganic layer materials, the multilayer barrier film exhibits excellent mechanical stress buffering.