High Efficiency and Low Roll-Off Pure-Red Perovskite LED Enabled by Simultaneously Inhibiting Auger and Trap Recombination of Quantum Dots.
basic_science · Level V
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- Record sourced from PubMed, PMID 38767286.
- Also identified by DOI 10.1021/acs.nanolett.4c01441.
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Abstract
CsPbI<sub>3</sub> perovskite quantum dots (QDs) could achieve pure-red emission by reducing their size, but the increased exciton binding energy (<i>E</i><sub>B</sub>) and surface defects for the small-sized QDs (SQDs) cause severe Auger and trap recombinations, thus worsening their electroluminescence (EL) performance. Herein, we utilize the dangling bonds of the SQDs as a driving force to accelerate KI dissolution to solve its low solubility in nonpolar solvents, thereby allowing K<sup>+</sup> and I<sup>-</sup> to bond to the surface of SQDs. The <i>E</i><sub>B</sub> of the SQDs was decreased from 305 to 51 meV because of the attraction of K<sup>+</sup> to electrons, meanwhile surface vacancies were passivated by K<sup>+</sup> and I<sup>-</sup>. The Auger and trap recombinations were simultaneously suppressed by this difunctional ligand. The SQD-based light-emitting diode showed a stable pure-red EL peak of 639 nm, an external quantum efficiency of 25.1% with low roll-off, and a brightness of 5934 cd m<sup>-2</sup>.