掺杂PPQ薄膜的电致发光及电场调制

Electroluminescence of Doped PPQ Thin Films Caused by Applied Field

从掺杂PPQ薄膜单层器件的电致发光光谱在掺杂前后的变化 ,说明掺杂PPQ薄膜中存在着基质分子和掺杂分子间的能量传递 ,其电致发光光谱随外加电场变化说明电场对PPQ薄膜的电致发光具有调制作用。用一个由单链模型扩展到包括杂质和外场的Hamiltonian进行数值求解。结果表明 :在PPQ和TPL分子之间有效的能量传递是源于它们之间的电荷转移 ,且随着外加电压的变化 ,其电致发光谱峰位的移动与掺杂前后系统总能量的改变及发光强度与掺杂后转移的电荷数之间分别存在对应关系。这一模型很好地解释了电场对PPQ薄膜电致发光的调制作用。

Poly-phenylquinoxaline (PPQ) was used as electroluminescent material and polymer thin films electroluminescent devices which were fabricated by means of spin coated method. After mixing with 1, 3, 5-triphenyl-2-pyrazotine (TPL), the changes of the fluorescence spectra for doping PPQ thin films and single layer device indicated the energy transfer between PPQ and TPL was occurred in electroluminescence of doping PPQ thin films. A model Hamiltonian was presented to describe the EL of PPQ thin films after doping. It was found that the effective energy transfer between PPQ and TPL was derived from the charge transfer between them. When applied fields change, the changes of the EL intensity are due to the charge transfer and the blue shift of the EL peak is attributed to the energy change caused by doping. The results are in agreement with experiments satisfactorily.