Preparation and the third-order optical nonlinearities of the sodium borosilicate glass doped with Cu7.2S4 quantum dots

► The Cu7.2S4 quantum dots were prepared by sol-gel and atmosphere control methods. ► The as-prepared Cu7.2S4 products were investigated by XRD, XPS, EDX and TEM. ► The optical absorption and transmittance spectra were also measured. ► The third-order optical nonlinearity was investigated by using Z-scan technique.