Quantification of deep hole-trap filling by molecular p-doping: Dependence on the host material purity
Quantification of deep hole-trap filling by molecular p-doping: Dependence on the host material purity
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DOI：
10.1016/j.orgel.2013.05.036
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发表时间：
2013-09-01
影响因子：
3.2
通讯作者：
Luessem, Bjoern
中科院分区：
文献类型：
--
作者：
Tietze, Max L.;Leo, Karl;Luessem, Bjoern
利用光电子能谱研究了不同纯度的N，N，N '，N'-四（4-甲氧基苯基）联苯胺（MeO-TPD）有机薄膜中氟化富勒烯C_（60）F_（36）的p掺杂效应。通过将摩尔掺杂比降低到MR = 2.9 × 10（-4），特别是在非常低的掺杂浓度下，解决了掺杂时的费米能级位移。与四次升华的MeO-TPD相比，5倍多的C60 F36分子必须掺杂到未纯化的MeO-TPD膜中以使费米能级移动到其本征位置上方。这一发现进行了讨论的统计模型，显示窄深空穴陷阱状态另外存在于未纯化的主机材料，这是阻碍了有效的生成的自由电荷载流子的摩尔掺杂比低于MR = 0.002。(C)2013爱思唯尔有限公司版权所有。
The p-doping effect of the fluorinated fullerene C60F36 doped into organic thin films of N,N,N',N'-tetrakis(4-methoxyphenyl)-benzidine (MeO-TPD) of different purification grades is systematically investigated by photoemission spectroscopy. By reducing the molar doping ratio to MR = 2.9 x 10(-4), the Fermi-level shift upon doping is resolved in particular at very low doping concentrations. In comparison to four times sublimated MeO-TPD, 5 times more C60F36 molecules have to be doped into unpurified MeO-TPD films to shift the Fermi-level just above its intrinsic position. This finding is discussed in terms of a statistical model, showing that narrow deep hole-trap states are additionally present in the unpurified host material which are hindering an efficient generation of free charge carriers at molar doping ratios below MR = 0.002. (C) 2013 Elsevier B.V. All rights reserved.