(472f) Development of Tandem Semiconductor Microparticles for Water-Splitting

There has been a vast improvement in photovoltaic (PV) technology in the last couple of decades; however, solar PV technology has a lot of drawbacks, including that it is intermittent, broadly dispersed and non-transportable. Hence, cost-effective solar energy storage is critical for widespread implementation of solar energy as the primary energy source. My project focuses on development of tandem semiconductor microparticles which, when placed in water under 1 Sun condition, will spontaneously split water into hydrogen and oxygen with solar-to-hydrogen efficiency of >10%. In the present work, we have acquired customized microwire array structures made on silicon wafer by deep reactive ion etching method and formed a diode on these particles via a doping process. We have also been able to produce a tandem junction for additional photovoltage. Some oxygen evolution catalyst was then deposited on the top subshell of the junction and the current-voltage characteristics was measured of this semiconductor assembly for oxygen evolution reaction.

Future work aims at detaching these particles from the Si substrate and suspending them in a metal precursor solution for depositing the hydrogen evolution catalyst. These particles will then be suspended in the electrolyte under 1 Sun condition and the evolved hydrogen will be measured by Gas Chromatography.