Comparison of buffer layers on SnS thin‐film solar cells prepared by co‐evaporation

Abstract

The binary compound SnS consists of elements that are non‐toxic, inexpensive, and abundant in the Earth's crust. It is a p‐type semiconductor with a band gap energy of 1.3 eV and an absorption coefficient of 104 cm−1, and is therefore a potential candidate for use as a solar cell absorber material. In this study, SLG/Mo/SnS/CdS/ZnO:Al/Al and SLG/Mo/SnS/ZnO/ZnO:Al/Al SnS thin‐film solar cells with different buffer layers were fabricated using a co‐evaporation method. The dependence of the photovoltaic properties of the SnS thin‐film solar cells with CdS or ZnO as the buffer layer was investigated. We demonstrate that the device with a ZnO buffer layer exhibited higher conversion efficiency and short‐circuit current density compared to the device with a CdS buffer layer.

Postdeposition Processing of SnS Thin Films and Solar Cells: Prospective Strategy To Obtain Large, Sintered, and Doped SnS Grains by Recrystallization in the Presence of a Metal Halide Flux

“…The growth followed the layered crystal structure of orthorhombic SnS, which is frequently observed in SnS growth by other methods due to the anisotropic growth rates of the planes. [14][15][16][17][18][19][20][21][22]29 There were no evident changes in the morphology and thickness of the SnS films after the AMPannealing and N 2 -annealing processes (Figures 1b and S2 in the Supporting Information). The energy-dispersive X-ray spectroscopy (EDS) analysis (not shown) of the as-deposited SnS indicates a stoichiometric composition, and after any of the annealing steps, no detectable changes in stoichiometry were observed.…”

“…The great deficiency in the open-circuit voltage ( V OC ) and the poor reproducibility remain the major challenges for SnS TFSCs. For most of the SnS-based devices, V OC values less than 0.25 V have been reported. − This result could be related to a number of material issues, including (i) low crystalline quality of the single-phase absorber material, i.e., a ribbonlike or layered structure with disordered growth orientations, a high concentration of defects, pinholes, and grain boundaries (GBs), as well as the presence of mixed phases (Sn 2 S 3 or SnS 2 polytypes), , which are detrimental to the PV performance; and (ii) poor device optimization, i.e., lattice mismatch, an unfavorable band offset between p-type SnS and n-type materials, and electrical back contacts. , …”

Fabrication of solar cells using Ge–Sn–S thin film prepared by co-evaporation

“…This morphology was similar to those prepared by our group in a previous study. 5) Furthermore, the grain size in the latter slightly increased with substrate temperature. A similar observation was reported in a previous study, wherein SnS thin films were prepared by co-evaporation.…”

“…1,2) SnS can be produced as both n-type and p-type. It has a band gap (E g ) of 1.3 eV [3][4][5][6][7][8][9] and a high optical absorption coefficient (over 10 4 cm −1 ), which makes it an ideal material for the fabrication of thin film solar cells. 4,6,7) In particular, solar cells utilizing homojunction with n-type SnS thin films are expected to become the target of future research due to their excellent properties.…”

“…10) SnS thin films have already been fabricated by various methods, namely, sputtering, 11) spin-coating, 12) chemical spray pyrolysis, 13) atomic layer deposition, 6,13) vapor transport deposition, 14,15) CVD, 16) sulfurization of evaporated precursors, 8,9) close space sublimation, 4) and co-evaporation. 3,5) Furthermore, SnS/CdS-based thin film solar cells have been reported to exhibit a power conversion efficiency (PCE) of 4.225%. 14) Yun et al reported a maximum PCE of 4.8% with nanostructured TiO 2 /SnS heterojunctions.…”