The imperative for solar research is obvious, and the pages of this issue of Photonics Focus should remind us how much scientific progress has been made in a short time.

Solar cell efficiency has increased from six percent in 1954 to a useful 25 percent today. Photovoltaic (PV) panels have become affordable and ubiquitous. And yet, researchers keep finding ways to improve them through new materials, designs, and construction methods. Innovative companies are laminating quantum dots into window glass to create transparent photovoltaics, which will increase the surface area of buildings available to harness sunlight for conversion to usable energy.

Other researchers are looking to water as a source of renewable energy: artificial photosynthesis remains tantalizingly close, and yet so far away.