Vacuum-Depositable Fluorinated Photoresist toward Organic Light-Emitting Diode (OLED) Patterning

In this letter, we report fluorinated photoresist (PR) formulations compatible with vacuum evaporation deposition, enabling fine pixel patterning for organic light-emitting diode (OLED) displays. Conventional solution-processable PRs, even when employing chemically orthogonal materials or passivation layers, must be created outside the vacuum chamber under ambient conditions, which risks degradation of sensitive organic semiconductor stacks. To address this limitation, we implemented vacuum-depositable PRs that can be applied within the same vacuum environment used for semiconductor layer deposition. The formulation consists of RF-SP, a spiropyran (SP) derivative that undergoes UV-induced photoisomerization to modulate solubility in fluorous solvents, and BNF-6, which functions as a diluent while enhancing the glass transition temperature and etch resistance. By tuning the RF-SP/BNF-6 ratio, the tone of PR patterns could be adjusted after development. This approach enabled successful photolithographic patterning of both electron-transport layers (ETLs) and emissive layers (EMLs), demonstrating strong potential for vacuum-based OLED fabrication.