Internally-externally defects-tailored MAPbI3 perovskites with highly enhanced air stability and quantum yield.

• Air-stable MAPbI 3 was fabricated by solvent dose control and ligand regulation. • The MAPbI 3 quantum dots exhibit high photoluminescence quantum yield up to 80%. • The quantum yield was still at 74% of its original value after 20 days. • The strategy is also suitable for preparing color-tunable MAPbX 3 (X = Cl, Br, I). Methyl-ammonium lead iodide (MAPbI 3) perovskite quantum dots (QDs) have emerged as a promising material for photoelectronic, however, they usually suffer intrinsically from the environmental instability and low photoluminescence quantum yield (PLQY), which will seriously impede their commercial applications. Here, we report an internal-external combination strategy by lowering the dose of good solvent and reducing the chain length of amine ligand to simultaneously enhance the air stability and PLQY of MAPbI 3 QDs. The low-dose solvent can effectively reduce internal iodine vacancies defects and external residual solvent molecules, meanwhile, the faster and denser assembly of nimble short-chain (SC) ligand on the MAPbI 3 QDs surface can helpfully enhance the external surface passivation. As a result, compared to MAPbI 3 QDs synthesized by traditional ligand-assisted reprecipitation (LARP) method, the air stability and PLQY of which are improved by more than four orders of magnitude (from a few minutes to dozens of days) and nearly two times (from 42% to 80%) prepared by our strategy. Besides, this strategy can widely tune the color of MAPbX 3 (X = Cl, Br, I) QDs from 388 to 735 nm through regulating components. This internal-external combination strategy can provide some beneficial enlightenment for preparing long-term air-stable hybrid perovskite QDs with high PLQY, which drastically driving their commercial applications. [ABSTRACT FROM AUTHOR]