側鏈含螢光性染料共聚合物之合成與光學性質探討

Abstract

本實驗主要合成一系列以styryl dyes為基礎之發光單體，再與不同比例之MMA單體(1：20~100)，以AIBN為起始劑行自由基聚合反應，得到一系列之側鏈含螢光性染料共聚合物，並以紫外線光譜分析共聚合物的成分組成比，由一系列的UV-vis及PL光譜測量下發現，由於自身淬息( self-quenching )會隨著濃度的增加而增加，而使得螢光量子效率及螢光強度在發光單體5/MMA單體莫耳比為(1：60~80)時達到最大值，另外，在導入不同取代基時發現，無論是在拉電子部份(benzothiazole)導入強拉電子基(-CN)；或是在推電子部份(NR2)之苯環上加入一推電子基(-CH3)，都會因推、拉電子相互作用加強，加強了charge separation，使得energy gap降低，而造成最大放射波長發生紅位移現象，而當取代基立體障礙較大時會使FWHM變窄。

Chromophores based on styryl dye moiety were synthesized. Free radical copolymerization of chromophores 5/methyl methacrylate(MMA) in molar ratios of 1/20、1/40、1/60、1/80and1/100were prepared. The copolymer composition were determined with UV-Visible spectroscopic analysis. The UV-Visible and PL spectra indicated that the self-quenching increased with increasing concentration of chromophre 5 in the copolymer compositions, leading to decreased fluorescence efficency(Φs/Φ0)、intensity of fluorescence and red shift ofλmax. In donor-acceptor chromophoric systems, the red shift ofλmax was observed which is due to strong donor-acceptor molecular interactions. Narrowing of FWHM was found when bulky side groups were introduced in the copolymer side chain.