A facile strategy to synthesize high colour purity blue luminescence aluminium-doped CsPbBr3 perovskite quantum dots

Recently, metal halide perovskite materials (CsPbX3, X = Cl, Br, and I) have attracted extensive attention for designing optoelectronic devices owing to their tuneable bandgap and high photoluminescence quantum yields (PLQYs). However, the corresponding study of CsPbX3 perovskite quantum dots (QDs) with blue luminescence still lags far behind that of their red and green counterparts. Herein, we developed aluminium (Al3+) ion-doped CsPbBr3 perovskite QDs through a supersaturated recrystallization synthetic approach at room temperature. The crystal structure and optical properties of the as-prepared QDs were systematically characterized. The results reveal that the particle size and lattice spacing of Al3+ ion-doped CsPbBr3 QDs decrease as the Al/Pb molar ratio increases, which is attributed to the radius of Al3+ ions being much smaller than Pb2+ ions. A significant blueshift in the luminescence from 503 nm to 465 nm of Al3+ ion-doped QDs is observed as the Al/Pb molar ratio increases. Moreover, high colour purity (wide full-width at half-maximum of 83.3 meV) blue photoluminescence emission at 465 nm with a PLQY of 65.7% is achieved when the Al/Pb ratio reaches 1.0 in the Al3+ ion-doped CsPbBr3 QDs, which shows good stability under ambient atmosphere. These as-prepared high colour purity blue luminescence Al3+ ion-doped CsPbBr3 QDs show promising potential in blue optoelectronic fields.