"Photostability and External Quantum Yield of Perylene Diimide Derivatives: Effects of Carbon-Chain Length and photo-induced carbon interactions in the long carbon chain PDIs"

Perylene diimide (PDI) derivatives are promising candidates for organic opto-electronics due to their strong luminescence and structural flexibility. We investigated four PDIs (C3, C5, C8, C13) with varying carbon chain lengths to evaluate photostability and quantum yield (QY) under continuous 447 nm laser excitation. Films prepared by drop-casting were characterized using photoluminescence spectroscopy, and ATR-FTIR. Results show that longer-chain PDIs (C5, C8, C13) retained higher QY and displayed improved resistance to degradation, due to packing effects from extended carbon chains, which reduce aggregation and the photo-induced carbon chain interactions in long carbon PDIs. Shorter chain derivative (C3) suffered significant PL intensity loss. These findings highlight the importance of molecular design in developing stable, high-efficiency PDI-based optoelectronic devices.