Planar defect-free pure red perovskite light-emitting diodes via metastable phase crystallization.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 36367940.
- Also identified by DOI 10.1126/sciadv.abq2321 and PMC identifier 9651863.
- Licence recorded as CC BY-NC.
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Abstract
Solution-processable all-inorganic CsPbI<sub>3-<i>x</i></sub>Br<i><sub>x</sub></i> perovskite holds great potential for pure red light-emitting diodes. However, the widely existing defects in this mixed halide perovskite markedly limit the efficiency and stability of present light-emitting diode devices. We here identify that intragrain Ruddlesden-Popper planar defects are primary forms of such defects in the CsPbI<sub>3-<i>x</i></sub>Br<i><sub>x</sub></i> thin film owing to the lattice strain caused by inhomogeneous halogen ion distribution. To eliminate these defects, we develop a stepwise metastable phase crystallization strategy to minimize the CsPbI<sub>3-<i>x</i></sub>Br<i><sub>x</sub></i> perovskite lattice strain, which brings planar defect-free CsPbI<sub>3-<i>x</i></sub>Br<i><sub>x</sub></i> thin film with improved radiative recombination, narrowed emission band, and enhanced spectral stability. Using these high-quality thin films, we fabricate spectrally stable pure red perovskite light-emitting diodes, showing 17.8% external quantum efficiency and 9000 candela meter<sup>-2</sup> brightness with color coordinates required by Rec. 2020.