The growing concerns of global warming, air pollution, and energy security caused by the usage of carbon-rich fossil fuels need to be addressed by developing energy technologies which are based on renewable energy sources. Harvesting solar energy appears to be the most practicable solution as the earth receives nearly 9600 times larger energy than today’s global energy consumption (17.91 TW in 2017). III-V semiconductors such as InP and GaAs have optimal bandgaps to achieve maximum solar to electricity conversion efficiency; however, their high material and manufacturing costs limit their utility for terrestrial applications. My research investigates cost-effective alternatives to current manufacturing technologies of III-V semiconductor-based solar energy devices.
In this talk, I will first discuss the surface engineering of InP using H2 plasma for high efficiency epitaxy-free InP heterojunction solar cells. By employing several optoelectronic and surface characterization techniques, we unveil the changes induced by H2 plasma resulting in a power conversion efficiency reaching 19.3%. Following this, I will introduce a new electron selective contact material, ferrihydrite (Fh) using simple solution processing. My work further demonstrates that Fh as an effective surface protection layer for InP photocathodes. I will discuss a comparatively new technique, known as spalling, used to obtain thin films of III-V semiconductors enabling reduced usage of III-V materials for solar device fabrication. As a proof of concept, InP thin films are used to fabricate heterojunction solar cells achieving an efficiency reaching 13%. Finally, I will discuss preliminary results of our novel tandem cell based on InGaAsP and perovskite solar cells. I will conclude by presenting future directions for obtaining cost-effective III-V solar energy devices.