Low Efficiency Roll-Off and High Current Efficiency Light-Emitting Diode Enabled by Graded CdSe/ZnSe/ZnS Colloidal Quantum Wells.
basic_science · Level V
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- Record sourced from PubMed, PMID 41603193.
- Also identified by DOI 10.1002/adma.202521504.
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Abstract
Colloidal quantum well light-emitting diodes (CQW-LEDs) hold tremendous potential for next-generation display and lighting applications, owing to their high color purity, excellent efficiency, and low fabrication cost. However, efficiency roll-off at high current density makes it challenging to achieve high brightness and long lifetime. Here, we designed CdSe/ZnSe/ZnS core/shell/shell CQWs with near-unity photoluminescence quantum yield. The graded heterostructure promotes carrier injection, and the bottom-emission device based on CdSe/ZnSe/ZnS CQWs exhibits remarkably suppressed efficiency roll-off with a record-high J<sub>90</sub> (current density for EQE to decrease to 90%) of 485 mA/cm<sup>2</sup> and a long operational lifetime (T<sub>95</sub> @ 100 cd/m<sup>2</sup>) over 47000 h. In addition, the top-emission device also shows low efficiency roll-off and high current efficiency of 36.5 cd/A. This study provides a compositionally graded approach to suppress efficiency roll-off in CQW-LEDs, demonstrating the strong potential of the newly developed CQWs for next-generation ultrabright and highly efficient optoelectronic devices.