Enhancement in the Efficiency of Sb2Se3 Thin-Film Solar Cells by Increasing Carrier Concertation and Inducing Columnar Growth of the Grains

Antimony selenide (Sb 2 Se 3 ) thin films are attractive light-absorbing materials for low-cost and highly efficient thin-film solar cells. Optimizing columnar growth of the grains and the proper hole concentration will be very helpful for improving the efficiency of Sb 2 Se 3 thin-film solar cells. In this paper, a monoatomic layer of Al 2 O 3 prepared by the atomic layer deposition (ALD) method is used to increase the hole concentration of the Sb 2 Se 3 film. The increase in the hole concentration is mainly due to the suppression of n-type defects, such as V se , or the increase in p-type defects, such as V sb . In addition, a simple and environmentally friendly oxygen plasma method is used to modify the CdS film to induce ordered columnar growth of the Sb 2 Se 3 film deposited by the rapid thermal evaporation (RTE) method. Finally, an oxygen plasma treatment on CdS and a monoatomic Al 2 O 3 layer covering the Sb 2 Se 3 was combined to fabricate a solar cell with a new structure, FTO/CdS/P-Sb 2 Se 3 /P + -Sb 2 Se 3 /Al 2 O 3 /Au, and its efficiency was increased from 2.48% to 6.7%. These simple, nontoxic, and industrially applicable methods provide potential avenues for preparing low-cost and highly efficient solar cells.