Efficient quantum dot light-emitting diodes with ultra-homogeneous and highly ordered quantum dot monolayer  

具有超均匀和高度有序量子点单层的高效量子点发光二极管

作　　者：Denglin Zhao Yueting Zheng Tingtao Meng Yangbin Zhu Jipeng Jing Xiang Chen Hongjin Gao Chaomin Mao Wenchen Zheng Hailong Hu Tailiang Guo Fushan Li 赵等临;郑悦婷;孟汀涛;朱阳斌;井继鹏;陈祥;高宏锦;毛超民;郑文晨;胡海龙;郭太良;李福山(Institute of Optoelectronic Technology,Fuzhou University,Fuzhou 350116,China;Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China,Fuzhou 350116,China)

机构地区：[1]Institute of Optoelectronic Technology,Fuzhou University,Fuzhou 350116,China [2]Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China,Fuzhou 350116,China

出　　处：《Science China Materials》2022年第3期757-763,共7页中国科学（材料科学（英文版）

基　　金：supported by the National Natural Science Foundation of China(62075043);Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(2021ZZ126)。

摘　　要：Regarding conventional quantum dot lightemitting diodes(QLEDs)fabricated by using the spin-coating(SC)technique,voids and interstitial spaces are inevitable due to unordered quantum dots(QDs)stacking,generating device leakage current under an external bias.In the present study,we fabricated an ultra-homogeneous and highly ordered QD monolayer by adopting the Langmuir-Blodgett(LB)technique.The QD monolayer was transferred as a emissive layer with a horizontal lifting(HL)method to a red QLED,which exhibited high performance with an external quantum efficiency(EQE)of 19.0% and lifetime(T_(95)@100 cd m^(-2))of13,324 h.When compared with the SC-based device,the EQE and lifetime were improved by 15% and 183% due to the compact and ordered QD monolayer that lowered the leakage current.Moreover,white QLEDs with stacked QD monolayers could be obtained at a low voltage of 4 V because LB technique is an organic-solvent-free approach avoiding interlayer mixing and controlling the QD layer thickness precisely.In addition,we successfully fabricated an ultra-homogeneous large-area QD monolayer on a rectangular substrate with a size of 9 cm×5 cm,indicating the promising size scalability of the LB-HL strategy.对于采用旋涂法制备量子点层的传统量子点发光二极管(QLEDs)而言,由于量子点有序性低,量子点薄膜不可避免地出现空隙,导致器件在偏压下产生漏电流.本研究中,我们利用Langmuir-Blodgett(LB)技术制备了超均匀、高度有序的量子点单层,并且采用水平提拉法(HL)将量子点单层作为发光层转移到红色QLEDs上,器件表现出了高性能,其外量子效率(EQE)为19.0%,寿命(T_(95)@100 cd m^(-2))为13,324 h.由于致密有序的量子点单层减少了漏电流,EQE和寿命分别提高了15%和183%.此外,LB技术是一种无有机溶剂气氛的方法,避免了层间互溶,同时也可以精确控制量子点薄膜的厚度,因此所制备的叠层白光QLEDs可以在4 V的低电压下获得白光.最后,我们成功地在9 cm×5 cm的矩形基板上制备了超均匀大面积量子点单层,表明LB-HL方法具有良好的尺寸可扩展性.

关 键 词：quantum dots LANGMUIR-BLODGETT quantum dot light-emitting diodes 

分 类 号：TN312.8[电子电信—物理电子学]