Selenisation optimization for nanoparticle based CIGSSe solar cells

Good selenization conditions are key to the performance enhancement of copper indium gallium sulfur selenide (CIGSSe) solar cells based on copper indium gallium sulphide ($\mathrm{Cu}(\mathrm{In}, \mathrm{Ga}) \mathrm{S}_{2}$) nanoparticle ink. Suitable selenization conditions are able to promote the growth of large grains in the light-absorbing layer of CIGSSe thin films, thus improving the CIGSSe solar cells performance and are of great importance for their industrialization. In this paper, $\mathrm{Cu}(\mathrm{In}, \mathrm{Ga}) \mathrm{S}_{2}$ nanoparticle were synthesized and their precursor thin filmw were selenised into a light-absorbing layers with large grains. After the selenization conditions were optimized, the power conversion efficiency (PCE) of the CIGSSe devices was $10.84 \%$. Using Xray diffraction (XRD) and field emission scanning electron microscopy (SEM) characterization methods, we found that under the optimized selenization conditions, sufficient large grain crystals produced in light absorbing layers which helps increase the device efficiency.