The Hunt for Electron Holes

The Hunt for Electron Holes
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The Hunt for Electron Holes
Hydrogen production using solar water splitting in photo electrochemical cells has been considered a breakthrough in energy research. Researchers have gained insight on iron oxide electrode and electronic structure. There is a possibility of affordable hydrogen production from solar energy. Hematite is a mineral form of iron oxide and an anode material for photoelectron chemical cells. It is affordable, available, and stable for solar spectrum. It has about fifteen percent solar-hydrogen conversion efficiency while its electronic structure allows ultra-short electron hole excited state lifetime.
From the article, it is shown that electrons carry a negative charge when they leave a place, and a “hole” is left. The “hole” behaves like positive charge. Holes are charge carriers. Sunlight causes electron hole pair formation in PEC electrode. In PEC photo anodes, which are made of hematite-generated holes, diffuse to semiconductor surface, they oxidise water to form oxygen. In hematite, photo generated holes recombine with electrons, before reaching the surface. Few holes reaching the surface limit the resulting photocurrent. Nanostructured morphology optimization of hematite photo anodes has led to performance improvement. However, the overall energy conversion remains at only a third of its potential.
Two hole types with different water splitting are formed in the hematite. This has effects on performance because it is hard to detect the holes. Additionally, the holes are elusive and transitional. Researchers studied nature of photo electrically generated holes in PEC. They gathered data when cell was in operation. Using soft X -ray absorption spectra under simulated sunlight, they identified two different hole transitions. The experiment as highlighted in th...