Green, pollution-free and low-cost semiconductor luminescent material based on CuAlInS quantum dots

Abstract

In recent years, CuInS2 quantum dots have shown great potential for various applications due to their wide excitation wavelength range, symmetric emission wavelength range, long fluorescence lifetime and optical stability. However, the high cost of indium (In) limits its commercialization. In this study, we partially substituted the expensive In element with more affordable and abundant aluminum (Al) to reduce the cost of CuInS2 quantum dots. CuInS2, CuAlInS, CuInS2/ZnS and CuAlInS/ZnS core/shell quantum dots were synthesized using one-pot method. Due to the incorporation of Al, their photoluminescence (PL) spectra exhibit a blue shift of about 5 nm. A time-resolved PL measurement indicated that the PL lifetime of the quantum dots was a characteristic feature of three dominating transitions from the conduction band to surface defect level, from the conduction band to an acceptor level, and from the donor level to an acceptor level. The temperature-dependent PL proves that after the introduction of Al, the FWHM of quantum dots does not show significant broadening with increasing temperature. Finally, CuInS2/ZnS and CuAlInS/ZnS quantum dot phosphor LEDs are produced. The brightness of the CuAlInS/ZnS quantum dot phosphor LED is slightly higher than that of CuInS2/ZnS quantum dot phosphor LEDs. The red-emitting CuAlInS/ZnS quantum dot phosphor LED with easy fabrication and no need for encapsulation can compensate for the lack of red light in warm white LED applications in future research.