Polyphenylene vinylene is capable of electroluminescence, leading to applications in polymer-based organic light emitting diodes. PPV was used as the emissive layer in the first polymer light-emitting diodes. Devices based on PPV emit yellow-green light, and derivatives of PPV obtained by substitution are often used when light of a different color is required. In presence of even a small amount of oxygen, singlet oxygen is formed during operation, by energy transfer from the excited polymer molecules to oxygen molecules. These oxygen radicals then attack the structure of the polymer, leading to its degradation. Special precautions therefore have to be kept during manufacturing of PPV in order to prevent oxygen contamination.