图9 恒流驱动下器件在3200 cd/m2、6000 cd/m2 和12000 cd/m2起始亮度下的亮度和时间归一化曲线

　　Fig.9 The normalized luminance decay curves of green OLEDmicrodisplays driven at a constant current with startingluminance of 3200, 6000 and 12000 cd/m2

　　根据器件在 3200 cd/m2、6000 cd/m2和12000 cd/m2起始亮度下的亮度衰减情况，采用公式(1)进行拟合计算[12-13]，公式如下：

　　公式(1)说明了器件的初始亮度与该初始亮度下的半衰期之间的关系。其中L0 为器件的初始亮度，t1/2为对应起始亮度衰减到一半的时间，也即为器件的半衰期，n 为加速系数。根据公式(1)从而推算出在特定使用亮度下的半衰期如表2 所示。

表2 推算出的器件半衰期

Table 2 Projected half-life in hours

　　4 总结

　　通过采用磷光体系材料和高效顶发射有机发光结构，配合SVGA060 全数字信号电路系统架构的CMOS 硅基驱动电路，获得了发光峰位于535 nm 的高亮度单色绿光、0.6 in、800×600 分辨率OLED 微显示器件，最大亮度可达20000 cd/m2。其起亮电压为2.6 V，亮度从20 cd/m2 到20000 cd/m2 的驱动电压摆幅为2.7 V，最大电流效率为24.43 cd/A。电流密度为20 mA/cm2 时，色坐标CIEX＝0.286、CIEY＝0.665。该器件在1000 cd/m2 和500 cd/m2 使用亮度下的半衰期寿命为42559 h 和186208 h。

　　作者：段 瑜，张筱丹，孙浩，朱亚安，王光华，宋立媛，于晓辉，万锐敏，季华夏，李亚文

　　参考文献：

　　[1] Wang J, Yu J S, Li L, et al. Low roll-off power efficiency organiclight-emitting diodes consisted of nondoped ultrathin phosphorescentlayer[J]. Applied Physics Letters, 2008, 92(13): 133308-1-3.

　　[2] Forrest S R. The road to high efficiency organic light emitting devices[J].Organic Electronics, 2003, 4(2-3): 45-48.

　　[3] Chen C W, Hsieh P Y, Chiang H H, et al. Top-emitting organic lightemitting devices using surface-modified Ag anode[J]. Applied PhysicsLetters, 2003, 83(25): 5127-5129.

　　[4] LU M H, Weaver M S, Zhou T X, et al. High-efficiency top-emittingorganic light emitting devices[J]. Applied Physics Letters, 2002, 81(21):3921-3923.

　　[5] Baldo M A, O’Brien D F, You Y, et al. Highly efficient phosphorescentemission from organic electroluminescent devices[J]. Nature, 1998,395(6698): 151-154.

　　[6] Tanaka D, Sasabe H, Li Y J, et al. Ultra high efficiency green organiclight-emitting devices[J]. Japanese Journal of Applied Physics, 2007, 46:10-12.

　　[7] Kondakov D Y, Sandifer J R, Tang C W, et al. Nonradiativerecombination centers and electrical aging of organic light-emittingdiodes: Direct connection between accumulation of trapped charge andluminance loss[J]. Journal of applied physics, 2003, 93(2): 1108-1119.

　　[8] Cleave V, Yahioglu G, Barny P L, et al. Harvesting singlet and tripletenergy in polymer LEDs[J]. Advanced Materials, 1999, 11(4): 285-288.

　　[9] Lane P A, Palilis L C, O’Brien D F, et al. Origin of electrophosphorescencefrom a doped polymer light emitting diode[J]. PhysicsReview B, 2001, 63: 235206 .

　　[10] Yang X H, Neher D, Scherf U, et al. Polymer electrophosphorescentdevices utilizing a ladder- type poly(-phenylene) host[J]. Journal ofApplied Physics, 2003, 93(8): 4413-4419.

　　[11] Levell J W, Gunning J P, Burn P L, et al. A phosphorescentpoly(dendrimer) with increased viscosity for solution-processed OLEDdevices[J]. Organic Electronics, 2010, 11(9): 1561-1568.

　　[12] Féry C, Racine B, Vaufrey D, et al. Physical mechanism responsible forthe stretched exponential decay behavior of aging organic light-emittingdiodes [J]. Applied Physics Letters, 2005, 87(21): 213502-203502-3.

　　[13] Lim Y B, Yoon D H, Kim H H, et al. Physical mechanism responsiblefor degradation of organic light-emitting diodes[J]. MicroelectronicEngineering, 2014, 129: 21-23.

　　分享到：

　　0 个人觉得赞好文章 点个赞您已经赞过了+1