Low-cost solar energy, a critical component in our future energy infrastructure, requires durable photovoltaic materials with long operating lifetimes. I work to improve this durability in two photovoltaic technologies: silicon and halide perovskites. For silicon, I develop a method to quantify moisture within standard modules, then examine the local impacts of water on performance losses in industrially-relevant module architectures over a range of environmental conditions. For halide perovskites, I develop an automation platform to rapidly synthesize and test absorbers with high precision, and apply it to screen for durable wide bandgap absorbers. The development of this platform yields software components of general interest for automation of materials research. Throughout my work I highlight the development of tailor-made tools that enable high-throughput investigation of photovoltaic materials.