Color-tunable ultralong-lifetime room temperature phosphorescence using phenylalanine derivative doped poly(vinyl alcohol) films

Doping chromophores in polymer matrixes to deliver room temperature phosphorescence (RTP) is well established. However, there are few examples of polymer-based RTP materials with ultralong phosphorescent lifetimes (>4 s) and afterglow (>30 s) under ambient conditions. We report a series of ultralong-lived RTP films by doping Phenylalanine (Phe) derivatives in a poly (vinyl alcohol) (PVA) matrix. The phosphorescence lifetime and efficiency of these films can be increased by introducing pentaerythritol (PER), an effect that is attributed to enhanced hydrogen-bonding interactions. The Fmoc-L-Phe@PER/PVA film exhibits a phosphorescence lifetime of 4.42 s and an afterglow duration of 46 s. Co-doping the PVA system with (Rhodamine B and Sulforhodamine B sodium salt) fluorescent dyes allows an adjustment of the afterglow from blue to red and pink. These films have been successfully applied in flexible luminescent materials, silk-screen printing, and multicolor afterglow light-emitting diode (LED) arrays.