聚合物电致发光二极管热特性研究

采用ANSYS有限元分析软件中热分析结构单元,对聚合物电致发光二极管(PLED)在光强为1000cd/m2时的热特性进行模拟,获得其温度场、热流分布及温度梯度的分布图,从仿真结果知PLED器件的最高温度为45.968℃,处于PFO-BT发光层,最低温度为45.95℃,处于石英玻璃基底末端.计算得出聚合物发光器件总热阻为1305℃/W,聚合物发光层至石英玻璃基底末端热阻为1℃/W.通过改变PLED器件输入功率、基底材料以及基底厚度3个参数,分别模拟得出其对PLED器件热特性的影响,仿真结果表明器件最高温度TH与输入功率P显现良好的线性关系;不同基底材料对器件温度影响小,负极端为器件主要散热通径;当基底厚度不断增加时,PLED器件最高温度随着增加,而最低温度不断减少,器件总热阻基本不变,发光层至石英基底末端热阻线性增大.

SIMULATION OF THERMAL PROPERTIES FOR POLYMER LIGHT-EMITTING DIODES

The thermal properties of polymer light-emitting diode(PLED) was simulated with the light intensity of 1000 cd /m2 by using the thermal structure element in ANSYS finite element analysis software.Temperature distribution,thermal flow distribution and thermal gradient distribution were obtained,the simulation results show that the maximum temperature is in 9,9-dioctylfluorene-co-2,1,3-benzothiadiazole(PFO-BT) emitting layer of the PLED device,with temperature of 45.968℃,the minimum temperature is at the end of the quartz glass substrate,about 45.95℃;the total thermal resistance is 1305℃ /W,but the thermal resistance between polymer light-emitting layer and the end of the quartz glass substrate is only 1℃ /W.The thermal properties of PLED devices according to different input powers,substrate materials and substrate thickness were compared.The simulation results indicates that the maximum temperature TH and the device input power P show a good linear relationship;the highest temperature of the PLED device changes slightly with changing quartz glass substrate to borosilicate glass substrate,the cathode side is the main route for heat dissipation;when the substrate thickness increases continuously,the maximum temperature TH increases at the same time,however the minimum temperature TL of PLED device decreases,the total thermal resistance of the PLED device is essentially the same,the thermal resistance between light-emitting layer and the end of quartz glass substrate rises linearly.These results provide a basis for the optimization of PLED devices.