Mixed-Halide Perovskites with Stabilized Bandgaps.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 28968126.
- Also identified by DOI 10.1021/acs.nanolett.7b03179.
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Abstract
One merit of organic-inorganic hybrid perovskites is their tunable bandgap by adjusting the halide stoichiometry, an aspect critical to their application in tandem solar cells, wavelength-tunable light emitting diodes (LEDs), and lasers. However, the phase separation of mixed-halide perovskites caused by light or applied bias results in undesirable recombination at iodide-rich domains, meaning open-circuit voltage (V<sub>OC</sub>) pinning in solar cells and infrared emission in LEDs. Here, we report an approach to suppress halide redistribution by self-assembled long-chain organic ammonium capping layers at nanometer-sized grain surfaces. Using the stable mixed-halide perovskite films, we are able to fabricate efficient and wavelength-tunable perovskite LEDs from infrared to green with high external quantum efficiencies of up to 5%, as well as linearly tuned V<sub>OC</sub> from 1.05 to 1.45 V in solar cells.