We developed a series of highly efficient blue electroluminescent polymers with dopantâhost systems and molecular dispersion features by selecting 1,8-naphthalimide derivatives as the light blue emissive dopant units, choosing polyfluorene as the deep blue emissive polymer host and covalently attaching the dopant units to the side chain of the polymer host. The polymers' EL spectra exhibited both deep blue emission from the polymer host and light blue emission from the dopant units because of the energy transfer and charge trapping from the polymer host to the dopant units. By modifying the chemical structures of the dopant units, we controlled the energy transfer and charge trapping from the polymer host to the dopant units and consequently tuned the emission colors of the resulting polymers. Thermally annealed single-layer devices (ITO/PEDOT/polymer/Ca/Al) based on these polymers emitted deep blue light with a luminous efficiency of 2.89 cd Aâ1, a power efficiency of 2.01 lm Wâ1 and CIE coordinates (0.16, 0.17), or emitted sky-blue light with a luminous efficiency of 6.84 cd Aâ1, a power efficiency of 4.28 lm Wâ1 and CIE coordinates (0.15, 0.22). Their excellent EL performances were due to the energy transfer and charge trapping from the polymer host to the highly fluorescent dopant units.
我们选择 1,8-
萘二甲
酰亚胺衍
生物作为浅蓝色发光掺杂单元,选择聚
芴作为深蓝色发光
聚合物宿主,并将掺杂单元共价连接到
聚合物宿主的侧链上,从而开发出一系列具有掺杂宿主体系和分子分散特性的高效蓝色电致发光
聚合物。由于从
聚合物主链到掺杂单元之间的能量转移和电荷捕获,
聚合物的电致发光光谱同时显示出
聚合物主链的深蓝色发射和掺杂单元的浅蓝色发射。通过改变掺杂单元的
化学结构,我们控制了从
聚合物宿主到掺杂单元的能量转移和电荷捕获,从而调整了所得
聚合物的发射颜色。基于这些
聚合物的单层器件(ITO/P
EDOT/
聚合物/Ca/Al)经热退火后发出深蓝色光,发光效率为 2.89 cd Aâ1,功率效率为 2.01 lm Wâ1,CIE 坐标为 0.16,0.17;或发出天蓝色光,发光效率为 6.84 cd Aâ1,功率效率为 4.28 lm Wâ1,CIE 坐标为 0.15,0.22。它们出色的电致发光性能得益于从
聚合物基体到高荧光掺杂单元的能量转移和电荷捕获。