Efficient persistent room temperature phosphorescence achieved through Zn2+ doped sodium carboxymethyl cellulose composites

Efficient room temperature phosphorescence (RTP) is rarely observed from rare metal or halogen free polymer materials. However, we have newly observed that Zn2+ doped sodium carboxymethyl cellulose emitting long-lasting phosphorescence at room temperature. It is ascribed to restricted molecular motions (RMM) from strong ionic band and abundant hydrogen bond in crystalline states. Such intermolecular and intramolecular interactions greatly rigidify the molecular conformation and drastically decrease the nonradiative deactivation channels of the triplet excitons, thus phosphorescent emission is greatly boosted at room temperature. The photoluminescence quantum yield and phosphorescence life time of Zn2+ doped carboxymethyl cellulose composites are up to 16.5% and 281 ms, respectively.