Cu-related defects and optical properties in copper–indium–selenide quantum dots by a green synthesis

Quantum dots of I–III–VI ternary compounds exhibit unusual photophysical properties and technological utility, which attract attention and have been intensely investigated. CuInSe2 quantum dots are an environmentally friendly composition, a direct transition, and an adjustable bandgap. Here, we discuss the influence of the Cu/In molar ratio of CuInSe2 quantum dots on Cu-related defects and photo-physical properties, and CuInSe2 quantum dots are synthesized by a green, safe, and low-temperature method in triethylene glycol. The proportion of the +1 and +2 oxidation states of Cu in the quantum dots will change with the Cu/In molar atomic ratio. The +1-oxidation state of Cu will prolong the carrier recombination lifetime and provide favorable conditions for the transfer and collection of carriers. By adjusting for different defect types, we can better apply CISe quantum dots in devices and other fields.