锗合金准二维钙钛矿发光二极管

Ge-alloyed Quasi-two-dimensional Perovskite Light-emitting Diodes

钙钛矿由于其出色的光电特性,在显示和照明领域具有潜在的应用价值。为降低重金属Pb含量,本文采用锗离子(Ge^(2+))部分取代Pb^(2+)进行合金化,并探索提高其电致发光性能的途径。由于Ge合金化可以使钙钛矿容忍因子更趋近于1,有望提高器件的发光稳定性。结果表明,Ge合金钙钛矿薄膜的光致发光性能在一定水氧条件下可以得到较大幅度提高,器件发光稳定性也同时得到提升。这主要归因于水氧共同作用使合金钙钛矿表面形成了GeO_(2),一定程度上钝化了钙钛矿薄膜表面缺陷,阻止了水氧的进一步渗透。得到的绿光PeLED器件最大外量子效率(EQE_(max))为11.8%,亮度为8×10^(3)cd/m^(2),较非合金化器件的发光寿命延长了3倍,在100 cd/m^(2)初始亮度下稳定性T50从~2 h提升至~6 h,这是目前文献报道Ge合金钙钛矿发光二极管最长的发光寿命。

Due to its excellent photoelectric characteristics and solution processability,perovskite has made unprecedented radical progress in the fields of display and lighting.In this paper,in order to reduce the content of Pb ion,we proposed to introduce germanium ions(Ge^(2+))into the perovskite lattice and realize partial substitution of Pb^(2+),then we explored ways to improve the performance.Because Ge alloying can make perovskite tolerance factor closer to 1,it is expected that device stability can be improved.The experimental results showed that the photoluminescence stability of Ge-alloyed perovskite films is greatly improved in a certain time under water and oxygen environment,and the PeLED device performance and operation stability are improved,which is mainly attributed to GeO_(2) formed on the surface of alloyed perovskite after the water and oxygen treatment.As a result,a green-light Ge-alloyed perovskite light-emitting diode was obtained with a maximum external quantum efficiency(EQE_(max))of 11.8%,maximum luminance of 8×10^(3)cd/m^(2).What􀆳s more,the device􀆳s lifetime was extended three times by germanium alloying,and the T50 of the device was improved from~2 h to~6 h with an initial brightness of 100 cd/m^(2),which is the longest luminous life of Ge-alloyed PeLEDs.