Heterostructured CdS Buffer Layer for Sb2Se3 Thin Film Solar Cell

The antimony selenide thin film solar cells technology becomes promising due to its excellent anisotropic charge transport and brilliant light absorption capability. Especially, the device performance heavily relies on the vertically oriented Sb 2 Se 3 grain to promote photoexcited carrier transport. However, crystalline orientation control has been a major issue in Sb 2 Se 3 thin film solar cells. Herein, a new strategy has been developed to tailor the crystal growth of Sb 2 Se 3 ribbons perpendicular to the substrate by using the structural heterostructured CdS buffer layer. The heterostructured CdS buffer layer is formed by a dual layer of CdS nanorods and nanoparticles. The hexagonal CdS nanorods passivated by a thin cubic CdS nanoparticle layer can promote [211] and [221] directional growth of Sb 2 Se 3 ribbons using a close space sublimation approach. The improved buffer/absorber interface, reduced interface defects, and recombination loss contribute to the improved device efficiency of 7.16%. This new structural heterostructured CdS buffer layer can regulate Sb 2 Se 3 nanoribbons crystal growth and pave the way to further improve the low‐dimensional chalcogenide thin film solar cell efficiency.