Quantum dots have received great interest due to their excellent optoelectronic properties. However, the surface defects of quantum dots affect the carrier transport and ultimately reduce the photovoltaic efficiency. In this paper, a core–shell quantum dot by hot-injection method is prepared to grow a narrow-band semiconductor layer (CuInSe 2 (CISe) quantumdot) on the surface of a broad-band core material (cadmium sulfide (CdS) nanocrystal). The composition, structure, optical properties, and decay lifetime of CdS/CISe core–shells are investigated in more detail by X-ray diffraction (XRD), transmission electron microscopy (TEM), photoluminescence (PL), UV–vis spectrophotometry, and fluorescence spectroscopy. The CdS/CISe core–shell structure has a broadened absorption range and still shows CISe-related quantum effects. The increased size of the core–shell and the smaller specific surface area of the CISe shell layer lead to a lower carrier complexation chance, which improves the carrier lifetime.
Quantum dots (QDs) of I-III-VI 2 ternary compounds, such as CuInSe 2 (CISe) and CuInS 2 (CIS), have broad application prospects as light-absorbing layers in solar cells due to their excellent photoelectric properties. Nevertheless, the presence of large numbers of surface defects in quantum dots will affect their performance. In this study, inverted type-I CdS/CISe core-shell QDs are successfully synthesized through thermal injection method in triethylene glycol, which is green and safe. By changing the molar ratios of CdS and CISe QDs, the components and optical properties of core-shell QDs are intensively studied by using different characterization methods (XRD, TEM, EDS, UV–vis, Raman, and fluorescence spectrum). The solar cells with the structure of FTO/TiO 2 /CdS/CdS/CISe/Mo are assembled, where the CdS/CISe core-shell QDs are used as absorption layers. The prepared devices exhibit an efficiency of 1.01% under an AM 1.5 G spectrum with a light intensity of 100 mW cm −2 .
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