MAPbBrxCl3-x quantum dots in Pb(OH)Br for stable blue light-emitting devices

Poor stability as an essential issue of metal halide perovskites (MHPs), limits their further applications in displaying and lighting. Among multicolor luminous MHPs, the development of blue luminous perovskite lags far behind that of red and green emission. Herein, a "MAPbBrxCl3-x quantum dots (QDs) in Pb(OH)Br" strategy is proposed, fabricating stable MAPbBrxCl3-x@Pb(OH)Br with the emission wavelength of 435–485 nm. Experimental characterizations indicate that cubic MAPbBrxCl3-x transforms into rectangular MAPbBrxCl3-x@Pb(OH)Br with the assistance of methylamine vapor. The as-prepared MAPbBrxCl3-x@Pb(OH)Br shows high stability of water, light, heat and organic solvents, which can emit bright emission even they are immersed in water for 6 months. In addition, anion exchange induced spectral shift of the MHPs are also suppressed due to the chemical inertness of Pb(OH)Br. Notably, this strategy is also applied to all inorganic halide perovskites. Blue light-emitting devices (LEDs) based on the MAPbBrxCl3-x@Pb(OH)Br have been demonstrated, which can run stably for over 8 h with brightness exceeding 1000 cd/m2 in a humid environment.