The effect of a complex A-site cation and mixed halides in the emission properties of perovskite quantum dots

Perovskite materials have attracted a great deal of attention due to interesting properties for several applications, such as photovoltaic devices, sensors or emitters. In this sense, lead perovskite quantum dots with a complex A-site cation and mixed halides (iodine and bromine), Cs0.1FA0.1MA0.8PbI3−xBrx, where x = 0, 1, 2 and 3, were synthesized in anhydrous toluene and characterized using different techniques. The influence of the complex A-site cation on luminescent emission was studied to compare both MAPbI3 and MAPbBr3 perovskite quantum dots. PL spectra revealed a red shift in the low wavelength zone of the emission spectrum for the triple cation lead iodide perovskite compared with the MAPbI3 and MAPbBr3 perovskite quantum dots. This was due to the composition of the A-site cation rather than a change in the crystalline structure, because no changes in crystalline structure was revealed by XRD. In the case of mixed halide perovskite quantum dots, a blue shift in high wavelength range was found with regard to the all-iodide perovskite, with a shift of the emission maximum in comparison with the methylammonium lead perovskite quantum dots. This is evidence of the influence of mixed halides and A-site cation compositions on the light emission of perovskite quantum dots, being affected different wavelength ranges in function of the composition of perovskite quantum dots.