Solution-processed quantum dot light-emitting diodes(QLEDs)hold great potential as competitive candidates for display and lighting applications.However,the serious energy disorder between the quantum dots(QDs)and hole...Solution-processed quantum dot light-emitting diodes(QLEDs)hold great potential as competitive candidates for display and lighting applications.However,the serious energy disorder between the quantum dots(QDs)and hole transport layer(HTL)makes it challenging to achieve high-performance devices at lower voltage ranges.Here,we introduce"giant"fully alloy CdZnSe/ZnSeS core/shell QDs(size~19 nm)as the emitting layer to build high-efficient and stable QLEDs.The synthesized CdZnSe-based QDs reveal a decreased ground-state band splitting,shallow valence band maximum,and improved quasi-Fermi level splitting,which effectively flatten the energy landscape between the QD layer and hole transport layer.The higher electron concentration and accelerated hole injection significantly promote the carrier radiative recombination dynamics.Consequently,CdZnSe-based device exhibits a high power conversion efficiency(PCE)of 27.3%and an ultra-low efficiency roll-off,with a high external quantum efficiency(EQE)exceeding 25%over a wide range of low driving voltages(1.8-3.0V)and low heat generation.The record-high luminance levels of 1,400 and 8,600 cd m^(-2)are achieved at bandgap voltages of 100%and 120%,respectively.Meanwhile,These LEDs show an unprecedented operation lifetime T_(95)(time for the luminance to decrease to 95%)of 72,968 h at 1,000 cd m^(-2).Our work points to a novel path to flatten energy landscape at the QD-related interface for solution-processedphotoelectronicdevices.展开更多
基金funded by the National Natural Science Foundation of China(Grant Nos.22205054,U22A2072,61922028,22175056,and 22479041)Zhongyuan High-Level Talents Special Support Plan(No.244200510009)+1 种基金the National Key R&D Program of China(Grant No.2023YFE0205000)Postdoctoral Research Grant in Henan Province(No.202103041).
文摘Solution-processed quantum dot light-emitting diodes(QLEDs)hold great potential as competitive candidates for display and lighting applications.However,the serious energy disorder between the quantum dots(QDs)and hole transport layer(HTL)makes it challenging to achieve high-performance devices at lower voltage ranges.Here,we introduce"giant"fully alloy CdZnSe/ZnSeS core/shell QDs(size~19 nm)as the emitting layer to build high-efficient and stable QLEDs.The synthesized CdZnSe-based QDs reveal a decreased ground-state band splitting,shallow valence band maximum,and improved quasi-Fermi level splitting,which effectively flatten the energy landscape between the QD layer and hole transport layer.The higher electron concentration and accelerated hole injection significantly promote the carrier radiative recombination dynamics.Consequently,CdZnSe-based device exhibits a high power conversion efficiency(PCE)of 27.3%and an ultra-low efficiency roll-off,with a high external quantum efficiency(EQE)exceeding 25%over a wide range of low driving voltages(1.8-3.0V)and low heat generation.The record-high luminance levels of 1,400 and 8,600 cd m^(-2)are achieved at bandgap voltages of 100%and 120%,respectively.Meanwhile,These LEDs show an unprecedented operation lifetime T_(95)(time for the luminance to decrease to 95%)of 72,968 h at 1,000 cd m^(-2).Our work points to a novel path to flatten energy landscape at the QD-related interface for solution-processedphotoelectronicdevices.
