Ti_(3)C_(2)T_(x)掺杂PEDOT:PSS提升蓝色量子点发光二极管性能

Boosting Performance of Blue Quantum-dot Light-emitting Diodes by Ti_(3)C_(2)T_(x) doped PEDOT∶PSS

空穴注入效率低是制约蓝色量子点发光二极管(QLEDs)性能的关键因素。通过提升PEDOT:PSS的电导率来增加器件的空穴注入效率是提升蓝色QLEDs性能的重要方向。由于二维材料碳化钛(Ti_(3)C_(2)T_(x))具有较高的导电性、丰富的表面官能团及良好的亲水性等优点,有望通过掺杂提高PEDOT:PSS的电导率。本文采用HCl/LiF刻蚀法制备了单层Ti_(3)C_(2)T_(x)纳米片,并将其掺杂到PEDOT:PSS中制备了蓝色QLEDs器件。结果表明,当Ti_(3)C_(2)T_(x)的掺杂量为0.1%时,器件的最大外量子效率和电流效率分别达到15.2%和14.42 cd·A^(-1),与参比器件的9.09%和7.68 cd·A^(-1)相比,分别提高了67%和87%。Ti_(3)C_(2)T_(x)纳米片对蓝色QLEDs器件性能提升有两个作用,一方面诱导PEDOT的构型从苯态到喹啉态转变,形成紧密堆积的大尺寸PEDOT纳米晶,并将这些导电纳米晶连接起来,构筑了新的电荷传输通道,提高了复合层的电导率;另一方面,通过掺杂实现了PEDOT:PSS功函数的调节,提升了蓝色QLEDs器件的空穴注入效率。

Low hole injection efficiency is a key factor limiting the performance of blue quantum dot light-emitting diodes(QLEDs).Improving the conductivity of PEDOT∶PSS to increase the hole injection efficiency of devices is of great importance for improving the performance of blue QLEDs.Because of the high conductivity,abundant surface functional groups,and good hydrophilicity of the two-dimensional material titanium carbide(Ti_(3)C_(2)T_(x)),the conduc⁃tivity of PEDOT∶PSS could be improved by using exfoliated Ti_(3)C_(2)T_(x) dopant.Here,the HCl/LiF etching method was employed to prepare single-layer Ti_(3)C_(2)T_(x) nanosheets and dope into PEDOT∶PSS for the fabrication of blue QLEDs de⁃vices.As a result,the blue QLEDs device using PEDOT∶PSS-0.1%Ti_(3)C_(2)T_(x) thin film as the hole injection layer pre⁃sented the EQE and current efficiency of 15.2%and 14.42 cd·A^(-1),respectively.Compared to the value of a refer⁃ence device of 9.09%and 7.68 cd·A^(-1),an great improvement of 67%and 87%were achieved,respectively.Ti_(3)C_(2)T_(x) nanosheets play a dual role in enhancing the performance of blue QLEDs.The Ti_(3)C_(2)T_(x) nanosheets induce a conformational change of PEDOT from a benzoid state to a quinoid state,forming densely packed large-sized PEDOT nanocrystals and connecting these conductive nanocrystals to construct new charge transfer pathways,which increase the conductivity of the composite layer.In addition,Ti_(3)C_(2)T_(x) doping realizes the work function regulation of PEDOT∶PSS,improving the hole injection efficiency of blue QLED devices.