8-羟基喹啉镧两亲性配合物LB膜的双层电致发光器件

Bilayer Electroluminescent Devices of Langmuir-Blodgett Films of Amphiphilic Complex Derivated from 8-Hydroxyquinoline Lanthanum

以具有不同层数的两亲配合物二 [2 -( N -十六烷基氨基甲酰基 ) -8-羟基喹啉 ]合镧 [La( HQ) 2 Cl]的 LB膜为发光层 ,PBD为电子传输层 ,制备了双层结构的电致发光 ( EL)器件 :ITO/LB膜 /PBD/Al.器件产生黄绿色注入式发光 .LB膜的层数和沉积压对器件的性能具有重要影响 .在 1 6V激发电压下 ,5 ,1 1和 2 1层LB膜双层 EL器件的电流密度分别为 4 8,2 9和 1 6.4 m A/cm2 ,启亮电压阀值为 7.5 ,8.5和 9.5 V.器件的亮度随电流密度和驱动电压的增加而增加 .在相同偏压下 ,2 1层 LB膜 EL器件的亮度大于 5和 1 1层 LB膜的器件 .在 2 5 m N/m沉积的 LB膜制备的 EL器件具有较高的亮度 ( 1 2 1 9cd/m2 )和击穿电压 .

Organic electroluminescent (EL) devices with a bilayer structure (ITO/LB film/PBD/Al) were fabricated with an Langmuir Blodgett (LB) film of amphiphilic complex bis[ N hexadecyl 8 hydroxy 2 quinoline carboxamide] lanthanum[La(HQ) 2Cl] as the emitting material. Excellent performance of the EL devices originates from the insertion of an electron transport layer between the electrode and the emitting layer. Greenish yellow EL emission with a luminance of about 1 219 cd/m 2 was observed with a low voltage drive(7.5 V). The number of the layers of LB films and the deposited surface pressure have a strong influence on the I V characteristics, EL intensity, as well as break down voltage of the EL devices. When the LB films were prepared at the surface pressure of 25 mN/m, the current density crossing this kind of diodes had stronger nonlinear I V characteristics and the organic EL device had a higher EL intensity than another device prepared at lower surface pressure(5 and 15 mN/m). At a lower surface pressure, there may be some point defects or pinholes in the LB film, in which the high tunnel current would increase exponentially with the field, leading to an increase in the current density crossing the EL device and a decrease in the recombination probability of electrons and holes at a higher voltage.