In the present work novel materials and solar cells based in silver antimony chalcogenides are developed by all-chemical deposition. A chemical formulation for the deposition of amorphous Ag-Sb-S thin films is presented. When this film is annealed, the formation of AgSbS2 is seen, which presents Eg of 1.79 eV, σlight = 1.6 × 10−5 Ω−1cm−1 with cubic crystalline structure similar to mineral cuboargyrite (a = 5.6520 Å). The heat treatment applied to AgSbS2 promotes a better crystallinity of the film but satisfactory grain growth for solar cell application is not achieved. The optical, electrical and structural parameters of the films are related to the heating process.
With the AgSbS2 thin film, some solar cells in superstrate configuration TCO/CdS/AgSbS2/C/Ag were developed. The main heterojunction is formed between cubic-CdS/cubic-AgSbS2, which has a lattice mismatch of 2.6 %. The best solar cell shows Voc = 0.625 V, Jsc = 1.35mA/cm2, FF = 0.64 and η = 0.54%. The problem of this solar cell is the lack of Jsc; for this reason the incorporation of Se into AgSbS2 is considered to form solid solutions which would enhance the optical absorption of the device.
The solid solution AgSbS1.3Se0.7 is obtained when an amorphous Ag-Sb-S film is heat-treated with a Se source (selenization). This film shows Eg = 1.47 eV and ∆σ = 1.6 × 10−5 Ω−1cm−1. The solar cell with the solid solution is designed in superstrate configuration where η = 0.65 % is obtained with the Voc = 0.527 V, Jsc = 2.07 mA/cm2 and FF = 0.60. The problem with this solar cells is still the lack of Jsc. To solve Se diffusion into CdS, a proof-of-concept solar cell in substrate configuration is presented: Mo/AgSb(SxSe1 – x)2AgSbS2/CdS/ZnO:Al.
Finally, an analysis of the heterojunction CdS/Absorber is made to estimate the length of the depletion region in equilibrium and under steady state illumination. With the parameters obtained during the analysis and experimental development of silver antimony chalcogenides, a simulation of solar cells is made using the software SCAPS- 1D. In this simulation the modification of film thickness for improve solar cell design is predicted to prevent optical losses. Further, some strategies for modify the back contact of solar cells to improve the performance are also presented.