The Development and Application of Novel Back-Contact Perovskite Solar Cells

In recent years, the efficiency of perovskite-based photovoltaic devices has risen drastically, now vying with silicon for the highest efficiency single-junction devices. This has led to an increased demand for devices that can be manufactured using scalable techniques, with some companies beginning small scale production of perovskite solar panels. One variety of perovskite solar cell that shows promise for a fully scaled product is that of the groove-based back-contact device. In this work the groove devices are characterised electronically, crystallographically and topographically to further understand their functionality. It is verified that the transport materials in the device are located on opposite walls of the grooves after evaporation and that the ETL interface is likely limiting in the efficiency of the complete devices. Roll-to-roll coated groove devices achieving over 12% stabilised PCE are then demonstrated, exceeding that of other back-contact architectures. We proceed to demonstrate reactive electron-beam evaporation as a method for depositing tin oxide in planar devices and we show that an ETL deposited in this way is able to achieve comparable efficiency and stability to that of solution processed from a nanoparticle solution.
Finally, we demonstrate a new perovskite ink with processing conditions appropriate for use in groove devices. We first establish this ink in planar devices and demonstrate over 18% PCE with short, low temperature annealing conditions and a solvent system compatible with groove devices. We briefly characterise films of this perovskite to evaluate the origin of the efficiency improvement. We then compare this to the formulation that achieved the previous champion groove devices and demonstrate a mean efficiency improvement of over 2% absolute, with comparable dark storage stability. This ink shows great promise for improving the efficiency and stability of groove devices using a versatile and scalable solvent system.