Structural and optical properties of Sm(DBM)3Phen doped in poly(methyl methacrylate) (PMMA): An evidence for cascading energy transfer process

Sm(DBM)3Phen complexes have been synthesized and studied in detail. X-ray diffraction analysis of Sm(DBM)3Phen complex reveals crystalline behavior. An enhancement in the fluorescence intensity as compared to the Sm(Phen)3·2H2O and Sm(DBM)3·2H2O samples has been observed. Stark splitting of the Sm3+ emission bands has also been observed. The fluorescence decay time for Sm3+ (4G5/2 → 6H9/2 transition) is seen to increase from 221.6 μs in Sm3+ to 232.6 μs in presence of Sm(DBM)3·2H2O and to 260.6 μs in Sm(DBM)3Phen. Energy transfer from excited Phen to DBM and finally from DBM to Sm3+ is proposed as the cause of the above observations.