Speaker
Description
Strong efforts are being carried out looking for efficient, clean and renewable energy sources to meet the decarbonization goals. With respect to solar energy, thin film photovoltaic (PV) systems based on CuInxGa1-xSe2 (CIGS) deserve special attention, due to its outstanding opto-electronic properties. Despite the high-efficiency devices produced by vacuum deposition processes, non-vacuum ones are desirable due to the lower cost of the process, scalability, and compatibility with large areas and flexible substrates. To date, solution-processed CIGS thin film solar cells with an efficiency of 17.3% [1] have been achieved, however highly toxic solvents are used.
To this end, a water-based ink comprising well-dispersed Cu, In and Ga oxides was screen-printed into fluorine tin oxide (FTO)-coated soda-lime glass (SLG). After deposition, selenization was used to convert the oxides into CIGS crystal and the resulting thin films show homogenous thickness of ≈2.5 µm and nominal Cu0.92(In0.77Ga0.31)Se2 composition. To complete the PV device, a buffer layer of CdS was deposited by chemical bath and the i-ZnO/ZnO:Al top conductive layers were sputtered. The resulting device revealed a record-breaking for screen printed CIGS photoabsorbers with 7.9% of efficiency (Figure 1a). Moreover, all-solution-processed CIGS PV cells with the same photoabsorber and CdS layers, and spray-coated water-based inks of i-ZnO/indium tin oxide (ITO) as top conductive layers were fabricated, demonstrating an efficiency of 2.2% (Figure 1b).
This abstract is being submitted for a poster presentation.
