Tandem Cu2O-covered silicon micropillar photocathodes for solar-to-fuel devices

At present, nearly 75% of the world’s energy consumption is supplied from fossil fuels such as coal, petroleum, and natural gas. A major part of this is utilized by the transportation sector and the remainder is used for electricity generation in power stations that burn fossil fuels. The combustion of fossil fuels to harvest their stored carbon-based energy is a primary source of greenhouse gas emissions, mainly in the form of carbon dioxide (CO2) and consequently is responsible for global warming. For these reasons, interest in and harvesting of solar energy as a crucial alternative clean energy source have developed quickly in current years. As a main source of energy, solar energy has the potential to deliver all energy desired by mankind.

Solar technology implementation has been broadly focused on electricity generation. Despite recent progress in solar electrical energy generation, important issues remain unsolved, such as the continued need for high-power energy demand for transport, central heating, and industrial processes, and the intermittency problem, such as caused by the alternation of summer and winter periods. One of the proposed solutions is to construct a solar-to-fuel (S2F) device, which describes the concept of turning solar energy into storable fuel. To fabricate a fully integrated, efficient S2F device based on photo-electricity, a single or set of semiconductors must be combined with a proper electrocatalyst. In this thesis, we show various geometries and materials combinations for a S2F device, primarily based on copper-based photocatalyst with structured silicon as a base material, employing device structuring and modification.