有机混合薄膜中的Frster能量转移

Frster Energy Transfer in Organic Blend Thin-Film

通过掺杂不同的染料有机电致发光器件可以得到不同颜色的光发射。掺杂小分子有机材料苝酸四甲酯perylene- 3,4,9,10 -tetracarboxylicacid(TMEP)到蓝色发光聚合物poly(N -vinyl carbazole)聚乙烯基咔唑(PVK),得到了很好的绿光发射。TEMP掺杂质量分数为0.01时,295. 5nm激发波长的荧光光谱可以明显观察到在420 nm处PVK和530 nm处TEMP的发射峰值;当TMEP掺杂质量分数达到0.050.10之间,器件的电致发光光谱和荧光光谱发射峰几乎完全被TEMP的绿光所占据。光谱的转移归因于从聚合物PVK到小分子有机材料TMEP的F -rster能量转移。荧光光谱中随着TMEP掺杂浓度的的增大发射峰值有明显的红移,这种现象被归因于在TMEP高浓度掺杂情况下激基缔合物的形成。激基缔合物的形成从TMEP在薄膜状态下与溶液状态下的荧光光谱的比较中得到证实。

The emission color of organic electroluminescent devices can be tuned by doping the active layer with certain dyes or other fluorescent molecules. We demonstrate the realization of green PLED by doping a blue light emitting polymer poly(N-vinyl-carbazole) (PVK) with a novel green light emitting molecule tetra-methylester of perylene-3,4,9,10-tetracarboxylicacid (TMEP). At TMEP 0.01 (mass ratio) doping concentration, excited by 295.5 nm, photoluminescence clearly show two emission peaks belonging to PVK and TMEP. For TMEP concentrations between 0.05\~0.10 (mass ratio) the photoluminescence (PL) and the electroluminescence (EL) spectrum of the TMEP/PVK blend are almost dominated by TMEP emission because of an excitation energy transfering from PVK to TMEP. The reason for the efficient energy transfering can be explained by the efficient Frster energy transfering from PVK to TMEP. PL spectra redshift with the increasing concentration of TMEP is due to the excimer formation. The difference between PL spectra of TMEP solution and PL spectra of TMEP solid film confirms the formation of excimer.