Fossil fuels upon which we have sustained our socio-economic growth are inherently unsustainable and are the prime contributor to global warming and climate change. Solar power is arguably the most promising renewable energy resource available to mankind for addressing the present-day energy conundrum. Solar power reserves are largely geopolitically unrestricted, and solar energy is freely and limitlessly available for the next few billion years.

There are two primary ways by which solar energy is harvested by material scientists. The first, photovoltaics (PV), concerns the direct conversion of solar to electrical energy.^1,2  The diffused availability and the intermittent nature of solar energy mandate the coupling of PV technology to mechanisms by which the energy can be stored. This can be achieved with photocatalysis,³  where solar energy is stored in the form of chemical bond energy of ‘solar fuels’.^4–6