Broadband visible emissions from sol–gel-derived silica/poly(vinyl pyrrolidone) hybrids

Photoluminescence (PL) of poly(vinyl pyrrolidone) (PVP) and silica/PVP hybrid films was investigated. The transparent PVP film was found to exhibit bluish PL centered at approximately 440 nm in response to ultraviolet (UV) light excitation. This PL behavior was made good use of in preparing luminescent silica/PVP hybrid films with high thermal stability at temperatures up to 250 °C. Europium-doped hybrid films exhibited white PL upon UV excitation, resulting from mixing of broadband PVP emissions and 5D0 → 7F2 emissions of Eu3+. Emission colors could be finely tuned by changing excitation wavelengths.