摘要
混合卤化物钙钛矿发光二极管(PeLEDs)在电压加载下常发生光谱变化现象,即所谓的色移,这严重不利于其在照明与显示领域的应用.对此,本文提出氢键键合的胺基掺杂策略以稳定混合卤素蓝光PeLEDs的发光颜色.通过选择胍(GA)和甲脒(FA)作为CsPbBr_(x)Cl_(3-x)量子点的胺基(-NH_(2))掺杂源,实验和理论研究结果揭示了在该-NH2和Pb-X晶格之间可以形成强N-H…X(X=Br/Cl)氢键相互作用,进而增加卤素阴离子的迁移势垒,抑制钙钛矿的离子迁移.最终经过胺基键合的蓝光器件展现出极佳的光谱和颜色稳定性,其发射峰位随着电压的增加几乎不发生偏移,分别固定于490.5(GA)和492.5 nm(FA),与未掺杂器件产生15 nm(从487 nm红移到502 nm)的红移形成了鲜明对比.此外,掺杂器件的最大外量子效率也从1.3%提高至3.02%(GA)和4.14%(FA).该工作为实现高效且颜色稳定的PeLEDs提供了便捷途径.
Voltage loading-induced change in the electroluminescence(EL)wavelength of mixed halide perovskite light-emitting diodes(PeLEDs),so-called color-shift,has become an inevitable phenomenon,which is seriously unfavorable to their applications in lighting and display.Here,we achieve color-stable blue PeLEDs via a hydrogen-bonded amine-group doping strategy.Selecting guanidine(GA)or formamidinium(FA)as amine-group(-NH_(2))doping source for CsPbBr_(x)Cl_(3-x)quantum dots(QDs),experimental and theoretical results reveal that the strong N-H…X(X=Br/Cl)bonding can be produced between-NH_(2)dopants and Pb-X lattices,thereby increasing the migration barrier of halide anions.Resultantly,color-stable sky-blue devices were realized with emission peaks fixed at 490.5(GA)and 492.5(FA)nm without any obvious shift as the voltage increases,in sharp contrast devices without N-H…X producing a 15 nm red-shift from 487 to 502 nm.Not only that,maximum external quantum efficiency is improved to 3.02%and 4.14%from the initial 1.3%.This finding offers a convenient boulevard to achieve color-stable PeLEDs with high efficiency.
作者
张枫娟
宋继中
蔡波
陈喜
魏昌庭
方涛
曾海波
Fengjuan Zhang;Jizhong Song;Bo Cai;Xi Chen;Changting Wei;Tao Fang;Haibo Zeng(School of Materials Science and Engineering,MIIT Key Laboratory of Advanced Display Materials and Devices,Institute of Optoelectronics&Nanomaterials,Nanjing University of Science and Technology,Nanjing 210094,China)
基金
the National Natural Science Foundation of China(61725402,51922049)
the Fundamental Research Funds for the Central Universities(30919012107,30920032102)
the National“Ten Thousand Talents Plan”Leading Talents(W03020394)
the Six Top Talent Innovation Teams of Jiangsu Province(TD-XCL-004)
the Natural Science Foundation of Jiangsu Province(BK2018002)。
