Visible-to-ultraviolet photon upconversion in poly(vinyl alcohol) films and unusual quenching by boric acid treatment

Abstract The photophysical characteristics of pyrene derivatives and Ir-complex pairs in nonstretched (NS-) and stretched (S-) poly(vinyl alcohol) (PVA) films are investigated. The NS-PVA film exhibits air-stable visible-to-ultraviolet (UV) photon upconversion when 1-pyrenebutyric acid is used as an emitter. The photophysical changes observed in the S-PVA films reveal that boric acid treatment unexpectedly quenches the upconverted UV emission.