Perovskite photovoltaics are a new class of light absorbers with exceptional and unparalleled progress in solar power performance. A perovskite is any material with a specific ABX3 crystal structure. In photovoltaic applications, the A cation can be either organic, inorganic, or hybrid in composition. The B component is typically a metal cation such as lead, and X is a halide such as iodine or bromine. Work on solar cells using perovskite materials has advanced rapidly as a result of the material’s excellent light absorption, charge-carrier mobilities, and lifetimes – resulting in high device efficiencies with low-cost, industry-scalable technology. While the potential for perovskite photovoltaic devices is high, commercialization will require overcoming other challenges relating to material stability, efficiency, and environmental compatibility.
In the application of single step, lead-halide perovskite inks to large-area substrates through slot-die, blade coating, or other roll-to-roll techniques, dramatic reductions in device performance may arise due to irregular solvent evaporation - particularly in mixed-solvent inks – resulting in the formation of microscopic cracks or crystalline defects in the deposited perovskite film.
To counteract such effects, researchers at NREL have developed additive enhancements that specifically address inherent difference in volatilities of mixed acetonitrile/methylamine perovskite inks. Through the use of Formamidinium Iodide (FA) and the additive application of methylethyl ketone (or a similar ketone or aldehyde with a similar boiling point), diisopropylethylamine, and methylammonium chloride, resulting in large-area perovskite films showing significantly improved uniformity of crystallization and solvent evaporation and a tremendous improvement in overall efficiency. Blade coating of this new perovskite ink results in a defect and crack-free film with a homogeneous deposition and the elimination of irregular drying patterns and hazing. This new ink can be used for PV, LED, and any other applications requiring a large area coating of perovskites.
This technology is within the Film Stability and Film Chemistry Engineering groups of NREL’s perovskite portfolio. For further information regarding NREL's broader perovskite portfolio, please visit NREL's Perovskite Patent Portfolio website.
Or contact licensing executive Bill Hadley at Bill.Hadley@nrel.gov.
Applications and Industries
- Photovoltaic and LED perovskite applications
- Dramatic reduction of defects and impurities in single-step perovskite inks deposited via reel-to-reel, slot die, and blade coating methods.
- Elimination of short circuit potential from cracks and performance-reducing flaws on perovskite films.