Development of light emitting devices using artificial photonic synthesis model dendrimers

聚合物激光器件作为下一代通信光纤受到了广泛关注。本文以光敏树枝状大分子为研究对象，通过分子内能量转移激发发色团（发射中心），采用组合方法合成了新型光敏树枝状大分子，并通过分支单元的蒽和核心单元的二萘嵌苯的直接偶联反应，研究了光敏树枝状大分子的放大自发辐射（ASE）。荧光测量结果表明，蒽基团的激发导致了芘的核发射，这表明含有这些树枝状大分子的旋涂聚苯乙烯薄膜被脉冲Nd：YAG激光的三次谐波（355 nm）激发。具有内壳蒽的树枝状聚合物的发射带的半高宽随着泵浦能量的增加而减小（FWHM=47 nm）。光谱变窄的原因是放大的自发辐射。同时，发射光谱几乎没有改变的树枝状大分子没有内壳蒽生色团（FWHM = 84 nm）。这些结果表明，放大的自发辐射的能量转移效率的影响。

Polymer laser devices attracted considerable attention for the next generation optical fiber for communications. In this works, we focused attention on photosensitized dendrimers as a novel polymer laser medium and measured amplified spontaneous emission (ASE) by chromophores (emission center) excitation through intramolecular energy transfer.Novel photosensitized dendrimers were synthesized by combinatorial method employing direct coupling reactions of anthracene of branch units and perylene of a core unit. The fluorescence measurement with these dendrimers revealed that excitation of the anthracene groups led to the perylene core emissions, indicating efficient energy transfer should be involved.Spin-coated polystyrene thin films containing those dendrimers were excited by the third harmonic of pulsed Nd: YAG laser (355 nm). The full width at half maximum of emission band of dendrimers having inner shell anthracene was decreased with increasing pumping energy (FWHM=47 nm). The spectral narrowing were attributed to the amplified spontaneous emission. Meanwhile, the emission spectra were hardly changed in the dendrimers without inner shell anthracene chromophores (FWHM = 84 nm). These results suggested that amplified spontaneous emission is affected by the energy transfer efficiency.