The scientific/technologic activities of SENSATE are divided into 4 complementary work packages. In the first workpackage, new materials and devices are modeled using advanced computational tools and machine learning concepts. In particular, the new class of chalco-halide compounds were modeled using density-functional-theory (DFT) calculations allowing to have a map of most relevant structural, optical and electrical properties of these materials. In addition, the combination of DFT with machine learning tools for the first time is expanding the capabilities of modelling of materials, thanks to the possibility to predict the properties of solid solution alloys in the complete composition range. Complementary, a baseline for device modeling was built and tested for different solar cell configurations, and the high potential of these materials for photovoltaic conversion demonstrated theoretically.
In the second workpackage, a complete screeing of electron and hole selective contacts was performed, defining the most suited devices architectures for the new materials under development. Deep surface analysis and chemical modification was performed, in order to manage the surface properties for interfaces optimization. On the other hand, a new type of conjugated electrolytes with fractal geometry have been developed as dipolar molecules for enhancing contact selectivity, and demonstrated for the first time in an emerging thin film technology.
In the third workpackage, a new methodology for the synthesis of complex van der Waals chalco-halide compounds was developed, based on the coevaporation of a chalcogenide compound a followed by a high pressure annealing. A completely new family of compounds including SbSI, SbSeI, SbSBr, SbSeBr, BiSI, BiSeI, BiSBr and BiSeBr were synthesized, and their quasi-one-dimensional structure demonstrated. Fundamental properties of these new type of materials were investigated through a complete advanced characterization, and the different possible applications of each of them was analysied.
Finally, in the fourth workpackage innovative solar cell prototypes were assembled and tested. In this sense, first solar cells reported ever with SbSeI and SbSeBr by physical vapor deposition techniques were obtained, with very promising efficiencies and open circuit voltages exceeding 600 mV, opening relevant perspectives for this new family of materials for energy applications.
