We show that converting the surfaces of lead halide perovskite to water-insoluble lead (II) oxysalt through reaction with sulfate or phosphate ions can effectively stabilize the perovskite surface and bulk material. These capping lead oxysalt thin layers enhance the water resistance of the perovskite films by forming strong chemical bonds. The wide-bandgap lead oxysalt layers also reduce the defect density on the perovskite surfaces by passivating undercoordinated surface lead centers, which are defect-nucleating sites. Formation of the lead oxysalt layer increases the carrier recombination lifetime and boosts the efficiency of the solar cells to 21.1%. Encapsulated devices stabilized by the lead oxysalt layers maintain 96.8% of their initial efficiency after operation at maximum power point under simulated air mass (AM) 1.5 G irradiation for 1200 hours at 65°C.
ultivated peanut or groundnut (A. hypogaea L.) is among the most important oil and food legumes, grown on 25 million ha between latitudes 40° N and 40° S with annual production of ~46 million tons (http://www.fao.org/faostat/en/#home). It presumably was domesticated in South America ~6,000 years ago and then was widely distributed in post-Columbian times 1. Combining richness in seed oil (~46-58%) and protein (~22-32%), peanut is important in fighting malnutrition and ensuring food security.
We alloyed Zn2+ into CsPbI3 perovskite nanocrystals
by partial substitution of Pb2+ with Zn2+, which
does not change their crystalline phase. The resulting alloyed CsPb0.64Zn0.36I3 nanocrystals exhibited an
improved, close-to-unity photoluminescence quantum yield of 98.5%
due to the increased radiative decay rate and the decreased non-radiative
decay rate. They also showed an enhanced stability, which correlated
with improved effective Goldschmidt tolerance factors, by the incorporation
of Zn2+ ions with a smaller radius than the Pb2+ ions. Simultaneously, the nanocrystals switched from n-type (for CsPbI3) to nearly ambipolar for the alloyed
nanoparticles. The hole injection barrier of electroluminescent LEDs
was effectively eliminated by using alloyed CsPb0.64Zn0.36I3 nanocrystals, and a high peak external quantum
efficiency of 15.1% has been achieved.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.