We utilize solution-based chemistries to synthesize novel nano- and polycrystalline solids and composites for energy conversion technologies, primarily in photovoltaics, but also batteries and catalysis. We see solution chemistry as the key to high-throughput, sustainable manufacturing, yet it introduces new challenges related to the inherently high defect-density of the resulting materials. To understand the unique physics of defect-dense materials and identify defect-tolerant compositions, we pair synthesis with studies of the spectroscopic, electronic and mechanical behavior of materials.