摘要
量子点材料由于具有发光范围可调性优异、发光颜色纯和量子效率高等特点,可作为发光层应用于显示器件中引起人们的广泛关注。目前市场上普遍使用的Ⅱ-Ⅵ族Cd类量子点的半高宽可以窄至20 nm以下,量子效率接近100%,光学性能优异,但其含有的重金属Cd元素限制了实际的应用。磷化铟量子点材料由于具有不含重金属元素、发光纯度及量子效率较高等特点,是一种理想的替代Cd类量子点的半导体纳米发光材料。然而,磷化铟量子点材料及其显示器件的性能与Cd类量子点及其器件性能相比仍然存在一定差距。近年来,通过反应过程中前驱体活性调节、表面控制、壳层的有效包覆等方面的改进,磷化铟量子点的颜色纯度和发光效率得到了大幅度的提升。目前磷化铟量子点的半高宽可以窄至35 nm,量子效率可达约93%。同时,通过器件结构的优化,磷化铟量子点显示器件的外量子效率已由2011年的0.008%提升到12%。为了获得发光性能优异的磷化铟量子点材料,可以通过使用不同磷源以及调节磷铟比例的方法有效控制反应前驱体的活性,通过长时间抽真空的方法有效抑制磷化铟量子点表面氧化层出现等来提高其颜色纯度。通过避免壳层生长过程中铟离子掺杂影响,及熵配体的引入等方法得到高量子效率的磷化铟量子点。同时,将光学性能优异的磷化铟量子点作为发光层应用于显示器件,并优化电子空穴传输层材料的性能和结构,可以有效提升器件的性能。本文围绕如何提高磷化铟量子点的发光颜色纯度和量子效率这两个方面的研究现状进行了总结,并介绍了磷化铟量子点在显示器件方面的应用进展,最后对磷化铟量子点材料合成、显示应用方面存在的问题以及今后的研究方向进行了讨论和展望,以期为制备高性能的磷化铟量子点材料及其显示器件提供参考。
Quantum dots(QDs)have attracted tremendous interest due to their excellent optical properties such as broad tunable emission,high color purity and quantum yield,and are employed in display application as emission layer.Cd-based QDs are generally usedin the commercial application for their narrow full width at half maximum(FWHM)of photo luminescent(PL)spectrum could be lower than 20 nm,high quantum yield(QY)up to about 100%.But the toxic heavy metal Cd is restricted in the actual application.Therefore,heavy metal free indium phosphine(InP)QDs is an attractive alternative for their relatively high color purity and high fluorescence.However,the optical properties of InP QDs and InP QDs based LED are worse than those of Cd-based QDs and Cd-based QLED,respectively.In the past few years,great improvement has been made through the control of precursors reactivity and the surface oxidation,effective growth of shell,and its FWHM could be as narrow as 35 nm,QY could be raised to^93%.Moreover,external quantum yield(EQE)of InP QDs based LED have been greatly improved form the promoting of QLED structure from 0.008%to 12%.To obtain InP QDs with high color purity,the precursors reactivity has been effective control through employing different kinds of phosphine precursor and different P∶In ratio,and the surface oxidation have been greatly inhibited through long time vacuum.To obtain InP QDs with high quantum yield,indium incorporation has been avoided during epitaxial growth of shell,and entropic ligands were introduced.After using InP QDs with excellent optical properties as emission layer,the electron and hole transporting layers with optimized structure,InP QDs based QLED have been obtained with both high EQE and luminescence.This review summarizes recent research development on how to obtain InP QDs with concurrent high color purity and PL QY.And the improvement of display application of InP QDs are also introduced.Finally,the challenges as well as the future directions of synthetic method and application in display are discussed.
作者
林拱立
杨志文
李万万
LIN Gongli;YANG Zhiwen;LI Wanwan(School of Materials Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2020年第23期23057-23063,共7页
Materials Reports
基金
上海市科委基础研究重大项目(16JC1400604)
国家自然科学基金(81671782)。
关键词
量子点
磷化铟
颜色纯度
量子效率
电致发光
显示器件
quantum dots
indium phosphide
color purity
quantum yield
electroluminescent
display device
