Platinum octaethylporphyrin (PtOEP) may be used as a fluorescent dye in the fabrication of polymer- and silica-based oxygen sensors. It is used as a red triplet emitting material with high external quantum yields for OLEDs. PtOEP is used as a dopant in host materials like CBP and Alq3. Its red emission is near 650 nm depending on host material and processing conditions.