All-Inorganic Hydrothermally Processed Semitransparent Sb<sub>2</sub>S<sub>3</sub> Solar Cells with CuSCN as the Hole Transport Layer
Pankaj Kumar, Martin Eriksson, Dzmitry S. Kharytonau, Shujie You, Marta Maria Natile, Alberto Vomiero
Abstract
High Resolution Image Download MS PowerPoint Slide An inorganic wide-bandgap hole transport layer (HTL), copper(I) thiocyanate (CuSCN), is employed in inorganic planar hydrothermally deposited Sb 2 S 3 solar cells. With excellent hole transport properties and uniform compact morphology, the solution-processed CuSCN layer suppresses the leakage current and improves charge selectivity in an n-i-p-type solar cell structure. The device without the HTL (FTO/CdS/Sb 2 S 3 /Au) delivers a modest power conversion efficiency (PCE) of 1.54%, which increases to 2.46% with the introduction of CuSCN (FTO/CdS/Sb 2 S 3 /CuSCN/Au). This PCE is a significant improvement compared with the previous reports of planar Sb 2 S 3 solar cells employing CuSCN. CuSCN is therefore a promising alternative to expensive and inherently unstable organic HTLs. In addition, CuSCN makes an excellent optically transparent (with average transmittance >90% in the visible region) and shunt-blocking HTL layer in pinhole-prone ultrathin (<100 nm) semitransparent absorber layers grown by green and facile hydrothermal deposition. A semitransparent device is fabricated using an ultrathin Au layer (∼10 nm) with a PCE of 2.13% and an average visible transmittance of 13.7%.