Single-source pulsed laser deposition of hybrid halide perovskites for solar cells

The world is rapidly shifting towards renewable and sustainable energy as we face concerns about climate change. In such times, the abundant energy from the sun is crucial in aiding this transition. The devices responsible for the conversion of solar energy into electricity are termed solar cells. Nowadays, the well-established photovoltaic (PV) industry belongs to silicon PV. Nevertheless, new materials are being researched to complement silicon PV technologies. Metal halide perovskites (MHPs) are one of the emerging solar cell technologies that have fascinated researchers due to their versatility in terms of both composition and fabrication methods, delivering power conversation efficiencies in pair-to-crystalline silicon cells, making them one of the best candidates for the next generation of photovoltaics. The construction of these emerging solar cell devices involves heterostructures containing an absorber material sandwiched between carrier-selective layers and electrodes. Challenges remain regarding upscalable fabrication methods compatible with integrating complex perovskite materials within heterostructures. Therefore, one of the main challenges addressed by the research within this PhD is the demonstration of an alternative physical vapor deposition (PVD) method known as pulsed laser deposition (PLD) for the growth of MHPs. The main motivation to employ PLD for growing MHPs is its unique capability to transfer highly complex chemical compositions from a single-source target to the substrate or a partial solar cell stack.
In this thesis, we have demonstrated the utility of PLD as an alternative PVD method for depositing complex MHP thin films with precise stoichiometry. Notably, this method exhibits compatibility with heterostructures and potential for scalability. This compatibility can be further enhanced by improving the hardware configuration of the PLD for wafer-scale area coatings and superior deposition rates. Additionally, we demonstrate PLD as an appealing deposition method for studying the growth of low- and wide-bandgap MHP. These materials pose challenges with alternative deposition methods due to constraints regarding the solubility of different precursors, varying solvent evaporation rates, or difficulties in reproducibility arising from the need to control four or more sublimation sources with significant differences in volatilities.