反向驱动的异质结有机薄膜电致发光

成功制备了结构为ITO／PDDOPV／PPQ／Al的异质结聚合物发光二极管。该器件在正反向偏压下均可发光。在正向偏压下的光发射主要来自PDDOPV，但在反向偏压下的光发射则包括来自PPQ的蓝光发射和PDDOPV的黄光发射。蓝光强度与黄光强度的比值随着反向偏压的增加而增加，当反向直流电压分别为22V、24V、26V、28V时，其电致发光光谱中PPQ与PDDOPV的峰高比IPPQ／IPDDOPV分别为1．092、1．329、1．605、2．046。换句话说，该器件的发光颜色是压控可调的，这对实现彩色显示是极为有利的。分析了在反向偏压下的发光机理以及IPPQ／IPDDOPV受电压控制的原因。

Organic Thin Film Electroluminescence Based on Heterojunction Under Reverse Drive

Light-emitting diodes based on heterojunction with structure ITO/PDDOPV/PPQ/Al have been successfully fabricated, in which PDDOPV {poly (2,5-bis (dodecyloxy)-phenylenevinylene]} is a hole transporting polymer while PPQ } is a hole transporting polymer while PPQ poly (phenyl quinoxaline)] is an electron transporting polymer. Light emission was observed under both positive and negative bias voltage. Light emission under positive bias voltage mainly is originated from PDDOPV, but light emission under negative bias voltage includes blue light emission which is from PPQ and yellow emission which is from PDDOPV. Intensity ratio of the blue emission to yellow emission increases with increasing negative bias, when the reverse applied voltage is 22 V, 24 V, 26 V, 28 V, respectively, the ratio of PPQ peak value to PDDOPV peak value, IPPQ/IPDDOPV are 1.092, 1.329, 1.605, 2.046 respectively. In other words, the emitting color is voltage-dependent color tunable, which is a promising property to realize colorful display. The light emitting mechanism under negative bias voltage is analyzed.