Remarkable Sb₂Se₃ Solar Cell with a Carbon Electrode by Tailoring Film Growth during the VTD Process

The vapor transport deposition (VTD) method is regarded as one of the most effective approaches to obtain high-quality Sb2Se3 thin films. However, the orientation and morphology of Sb2Se3 limit the development of Sb2Se3 solar cells. Thus, a method to tailor the surface morphology of Sb2Se3 film growth by VTD is urgently needed. In this work, the growth of the Sb2Se3 thin film and the formation mechanism of Sb2Se3 nanorods appearing on the Sb2Se3 film are carefully studied. Sb2Se3 nanorods with [hk1] orientation and [hk0] orientation are distinguished. By controlling the growth of Sb2Se3 nanorods with [hk1] orientation, the interface defect density is reduced and the quality of the Sb2Se3 thin film is improved. Finally, Sb2Se3 solar cells with the configuration ITO/CdS/Sb2Se3/C/Ag achieve an efficiency of 6.09% with an open circuit voltage (Voc) deficit decreased by 34 mV, wherein over 85% of the efficiency of the Sb2Se3 device remains after replacing the Spiro-OMeTAD/Au structure with a carbon/Ag structure. This value is the champion efficiency for a VTD-processed Sb2Se3 solar cell with a carbon electrode. This work is expected to offer valuable information for the future development of Sb2Se3 or/and other highly anisotropic materials formed by physical vapor deposition.