Photocaged Perylene Diimide Precursor for Precise Solubility Control and High‐Quality Film Fabrication

Abstract The inherent contradiction between solubility and electronic properties remains a key challenge limiting the wide application of perylene diimides (PDIs). Here, a novel photocaged precursor strategy is proposed to realize precise solubility transitions by photo‐control and to prepare insoluble PDI films directly by irradiating the solution without additional thermal or chemical post‐processing. To this end, a specifically designed soluble PDI precursor, N, N’ ‐di‐5‐(dodecyloxy)‐2‐nitrobenzyl acetate‐3, 4, 9, 10‐perylenetetracarboxylic diimide, is synthesized by linking solubilizing chains to the imide ‐position via photocleavable o ‐nitrobenzyl (ONB) photocaged group. Upon irradiation at 365 nm, the ONB‐linker breaks effectively, removing the solubilizing chains precisely and yielding an insoluble PDI derivative. Spectroscopy results reveal that the photocleavable behavior is effective in both solution and solid states (>76% conversion within 600 s in solution). High‐quality insoluble PDI films with favorable flatness and continuity (surface roughness 2.8 nm) and promising conductivity (3.7 × 10 −2 S cm −1 after chemical doping) are prepared directly in solution by irradiation. This study establishes, for the first time, a universal and spatiotemporally controllable strategy for the direct preparation of insoluble PDI film, offering a new idea for balancing the solubility and charge transport properties, and a potential guideline for solution processing of high‐performance, low‐solubility organic semiconductors.