Publication date: 1st July 2014
Hybrid solar cells have opened the path for novel designs aimed to increase the efficiency of solution processed semiconductor solar cells. The combination of conductive polymers with oxide matrices was quickly dominated by architectures based on poly-3-hexyl-thiophene (P3HT) and TiO2. Promising results were obtained with the structure TiO2/ Sb2S3/P3HT, motivating the present contribution. We compare alternative methods to obtain this architecture, and report its impact on the performance of TiO2 based hybrid solar cells. For that purpose, different TiO2 matrices were fabricated by screen printing (nanoparticles) and solvothermal method (1D nanostructures), and sensitized with Sb2S3 by chemical bath deposition. Optimization of film thickness, mass ratio, annealing treatments, was followed by TEM and SEM techniques. The performance of the Sb2S3-sensitized TiO2 matrices/P3HT hybrid solar cells was investigated using electrochemical impedance spectroscopy (EIS). Important differences in light-harvesting and charge-carrier transport are anticipated due to the different morphologies and surface chemistry of the TiO2 matrices.