Sb₂Se₃ Thin‐Film Photovoltaics Using Aqueous Solution Sprayed SnO₂ as the Buffer Layer

Abstract

Sb2Se3 is a promising photovoltaic material due to its suitable bandgap, strong light absorption, simple phase, nontoxicity, and earth‐abundant constituents. Currently, most Sb2Se3 thin‐film solar cells are based on toxic CdS as the buffer layer. Here, for the first time, non‐toxic, wide‐bandgap, and chemically stable SnO2 is introduced as the buffer layer instead of CdS to build superstrate SnO2/Sb2Se3 thin‐film solar cells. The phase of sprayed SnO2 films and device band alignment are investigated in detail. SnO2 buffer layer annealed at 480 °C exhibits the lowest interfacial defect density and best device performance. Finally, 3.05% efficiency is achieved and the devices show excellent storage and light‐soaking stability. This preliminary experimental study implies that SnO2 has potential for developing high‐efficiency, stable, and environmentally friendly Sb2Se3‐based solar cells.

Review of Recent Progress in Antimony Chalcogenide‐Based Solar Cells: Materials and Devices

“…For example, a CdS ETL works best for Sb 2 Se 3 solar cells, and Sb 2 S 3 and Sb 2 (S x Se 1−x ) 3 solar cells based on SnO 2 ETL generally show better performances. It's noted that Sb 2 Se 3 solar cells using an high‐temperature solution processed SnO 2 as an ETL delivered low efficiency compared with those of CdS and ZnO ETLs . Based on our understanding of SnO 2 from previous review papers, we believe the reason for this low efficiency is that high‐temperature processed SnO 2 ETL cannot effectively block holes compared with the low‐temperature processed ETLs, leading to severe interface recombination and shunt paths.…”

“…Interfacial Engineering : Interfacial engineering improvements of planar Sb 2 Se 3 solar cells were mainly focused on developing alternative ETLs or highly efficient HTLs. Apart from the widely used CdS, TiO 2 and ZnO ETLs, wide‐bandgap Mg‐doped ZnO and SnO 2 have been demonstrated to work as efficient alternative ETLs for planar Sb 2 Se 3 heterojunction solar cells . Recently, PbS colloidal quantum dot films were used as HTLs for planar Sb 2 Se 3 solar cells, which not only minimizes the carrier recombination loss at the back contact and boosts the carrier transport efficacy but also contributes to the photocurrent by its own near‐infrared absorption …”

Sb2(Se1‐xSx)3 Thin‐Film Solar Cells Fabricated by Single‐Source Vapor Transport Deposition

“…Materials and device characterization are similar to our previous reports . The morphologies and EDS characterization of Sb 2 (Se 1−x S x ) 3 films were checked by scanning electron microscopy (FEI Nova NanoSEM450, without Pt coating).…”

Promising Sb2(S,Se)3 Solar Cells with High Open Voltage by Application of a TiO2/CdS Double Buffer Layer

“…It has been demonstrated that the transportation of electrons between the absorber layer and the electron transporting layer can make a great influence on the PCE of Sb 2 (S,Se) 3 thin film solar cells by tuning the band gap offset at the interface . In addition, series works basing on various electron transporting layer have been carried out by Tang's group, which revealed that the selection of a better electron transporting layer for Sb 2 (S,Se) 3 thin film solar cells is very important. But so far few works were carried out on the band gap engineering between Sb 2 (S,Se) 3 absorber layer and n type films.…”