SYNTHESIS OF AN ACRYLIC COPOLYMER BEARING FLUORESCENT DYE PENDANTS AND CHARACTERIZATION AS A LUMINESCENCE CONVERSION MATERIAL IN FABRICATION OF A LUMINESCENCE CONVERSION LIGHT-EMITTING DIODE

Abstract A polymerizable arcyl group was incorporated into modified 4- N , N -diphenyl-9-(4- tert -butylphenyl)-1,8-naphthalimide (DBN), and the resulting compound (P-DBN) was copolymerized with methyl methacrylate (MMA) to obtain the corresponding copolymer (PMMA- co -DBN). A DBN/PMMA blend film underwent phase separation upon heating, while PMMA- co -DBN did not exhibit the phase separation problem under the same conditions. However, the fluorescence quantum yield ( Ф rel ) of P-DBN was much lower (65%) than that of free DBN, and the Ф rel of PMMA- co -DBN (36%) was lower still. The luminescent output power of a luminescence conversion light-emitting diode (LUCO LED), fabricated using PMMA- co -DBN, was not detectably changed during 288 h of operation at 20 mA, due to adequate stability of the copolymer under the experimental conditions.