Ultralong Room‐Temperature Phosphorescence from Amorphous Polymer Poly(Styrene Sulfonic Acid) in Air in the Dry Solid State

Abstract Polymer‐based room‐temperature‐phosphorescent (RTP) materials are attractive alternatives to low‐molecular‐weight organic RTP compounds because they can form self‐standing transparent films with high thermal stability. However, their RTP lifetimes in air are usually short (<≈0.4 s). Here, the simple organic amorphous polymer, poly(styrene sulfonic acid) (PSS), exhibits an ultralong RTP lifetime in air when desiccated. The maximum lifetime is 1.22 s, which is three times that of previously reported RTP amorphous organic polymers. The lifetime can be controlled by the PSS molecular weight and by the ratio of sulfonic acid groups introduced into the polymer. The dry polymers should enable unprecedented molecular engineering in organic molecule‐based optoelectronic devices because of the self‐standing and thermal stability attributes.