利用瞬态电致发光方法研究有机电致发光器件内部电荷行为
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摘要
利用自主搭建的瞬态电致发光测量系统,连续施加两个电压相同的矩形脉冲作为器件驱动电压并且两个矩形脉冲之间存在一定的时间间隔,通过测量器件的瞬态EL和瞬态电流,从而分析研究器件内部电荷存储行为和发光过程。之前的研究发现了m-MTDATA∶3TPYMB混合发光层是激基复合物的发光,并且发现了其较长延迟发光是因为空穴传输层和电子传输层内储存的电荷再复合造成的。制备了以m-MTDATA∶3TPYMB(1∶1)混合层作为发光层、m-MTDATA作为空穴传输层、3TPYMB作为电子传输层的一组器件,通过对器件瞬态EL的分析,发现在第二个脉冲驱动下器件的EL强度稳定值比第一驱动驱动下的EL强度稳定值大,且第二脉冲的EL强度稳定值与第一脉冲EL强度稳定值的比值随通过器件的电流增大而减小,实验还发现第二脉冲撤销时的延迟发光衰减速度要比第一脉冲撤销时的快,这是由于第二脉冲撤销时发光层内极化子(电荷)对激子的猝灭(TPQ)比较严重。
Transient electroluminescent measurement system is used to study the inside charge behavior of prepared organic lightemitting diodes(OLEDs)in this article.Two rectangular pulses with a fixed time interval are supplied on the device.We can analyze the inside charge storage and the emitting process by measuring the transient EL and transient current of the device.OLEDs based on the m-MTDATA∶3TPYMB(1∶1)system was prepared.We found that the stable EL intensity increase when the second pulse is supplied.And the increment reduced with the increased current.We also find the electroluminescent under the second pulse decayed faster than that of the first pulse.This is because of the quenching due to the polaron-exciton effect(TPQ)is more serious in the emitting layer under the second pulse.
Transient electroluminescent measurement system is used to study the inside charge behavior of prepared organic lightemitting diodes(OLEDs)in this article.Two rectangular pulses with a fixed time interval are supplied on the device.We can analyze the inside charge storage and the emitting process by measuring the transient EL and transient current of the device.OLEDs based on the m-MTDATA∶3TPYMB(1∶1)system was prepared.We found that the stable EL intensity increase when the second pulse is supplied.And the increment reduced with the increased current.We also find the electroluminescent under the second pulse decayed faster than that of the first pulse.This is because of the quenching due to the polaron-exciton effect(TPQ)is more serious in the emitting layer under the second pulse.
引文
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[3]Bolton O,Lee K,Kim H J,et al.Nat.Chem.,2011,3(3):205.
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[5]Kondakov D,Pawlik T,Hatwar T,et al.J.Appl.Phys.,2009,106(12):124510.
[6]Chowdhury A,Pal A J.Synthetic Metals,2001,122:243.
[7]Jankus V,Chiang C J,Dias F,et al.Adv.Mater.,2013,25(10):1455.
[8]Li J,Nakagawa T,MacDonald J,et al.Adv.Mater.,2013,25(24):3319.
[9]Hossein ZamaniSiboni,Hany Aziz.Appl.Phys.Lett.,2012 101:063502.
[10]Huang Qingyu,Zhao Suling,Xu Zheng.Appl.Phys.Lett.,2014,104:161112.