Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV24)
Publication date: 6th February 2024
This project aims in development and study of hybrid solar cells based on FexZn1-xS with P3HT to obtain a solar cell with greater conversion efficiency of energy.
Thin films of FexZn1-xS were obtained by an electrochemical method. The synthesis was carried out by chronoamperometry in a 3 electrodes cell, where the working electrode was ITO glass, Pt wire as a counter-electrode and Ag/AgCl as reference electrode. The electrochemical bath was prepared with 10 mL of FeSO4 30 mM, 10 mL of ZnSO4•7H2O 30 mM and 20 mL of thiourea 30 mM and it was completed to100 mL with water. pH was adjusted to 2.5 with H2SO4 and the reaction was carried out at room temperature for 600 s. The reaction was performed varying the potential (-1.2, -1.5 and -1.7 V) and the molar ratio of Fe:Zn (3:1, 2:1, 1:1).
The chonoamperogram shows the growth mechanism of the thin film on the ITO surface. Three different processes may be observed, the breaking of the double layer, the nucleation process and the growth process. The optical characterization by UV-vis shows absorption at 350-400 nm related to the presence of ZnS and a second absorption at 650 nm attributed to the Fe presence. The Fe content affects the optical properties of the materials, showing higher wavelengths as the Fe content increases. SEM images show a regular deposition with the absence of pores, in addition, when the content of Fe increases, the definition of the morphology and the particle size are better defined.
After the obtention of the ternary material, a solution of P3HT was deposited on top of the semiconductor by the spin coating methods at 4000 RPM. In addition, a solution of PEDOT:PSS 1.3% in water was deposited by spin coating in half of the cells in order to study the influence of a hole transport layer on the efficiency of the cell. Finally, a counter electrode of Au was apply by sputtering, in order to close the circuit.
The result shows then increasing the amount of iron on the material produces a higher conductivity, what derivates in a better charge transportation in to the solar cell and a better efficiency. The precense of a HTL did not show a important influence on the efficiency of the solar cell, this indicates that the composition of the ternary, specially the addition of Fe to the crystalline structure determines the performance of the solar cell.
The authors acknowledge the School of Chemistry of Universidad Autónoma de Nuevo Leon for the facilities and the founding of this project.