From Ternary to Quaternary: Dual-emission Mechanism and Photoluminescence Spectra Tunability Expansion of I-III-VI Al-based Quantum Dots

I-III-VI alloyed quantum dots (QDs) have shown great application potential in many fields. At present, Al-based alloyed QDs have become a kind of ideal material of the color conversion layer of WLEDs because of their blue-emission, abundant raw material content, and the strong stability of Aluminum oxides. In this study, we synthesized blue-emitting CuAlSe 2 /ZnSe QDs and dual-emitting CuAlGaSe/ZnSe QDs by using hot-injection and one-pot method respectively, with a photoluminescence quantum yield (PL QY) of 46.75% and 68.79%. Their spectral tuning effect and the luminescence mechanism were investigated and discussed by changing the elemental molar ratios and nucleation temperature. By changing the Cu/(Al+Ga) and Al/Ga molar ratio, the emission wavelength of CuAlGaSe/ZnSe QDs was adjustable from 456   nm to 631   nm, with the Al and Ga competition mechanism in CuAlGaSe/ZnSe was also proposed. Finally, a single-component dual-emission CuAlGaSe/ZnSe WLED with a color rendering index (Ra) of 91.4 was prepared. This work demonstrated the superior fluorescence performance of multi-component QDs and the potential application of Al-based QDs in WLEDs.