Photovoltaic Solar Panel
why are Photovoltaic Solar panels “relatively inefficient”?
Does it have to do with a “small” number of photons striking the panel relative to the size of the panel (i.e. panel would have to be huge) – or the inability of the cells to utilize all of the photons striking the panel (i.e. more photons bouncing off than utilized) or something completely different.
The wavelength of light needs to be closely matched to the bandgap of the semiconductor material. Some newer, multilayer photovoltaic cells are more efficient because each layer absorbs photons of a different wavelength. They already use antilreflective coatings to reduce reflected light.