Characteristics of photocurrent generation in the near-ultraviolet region in Si quantum-dot sensitized solar cells

• We have developed on Si quantum-dot sensitized solar cells using Si particles.
• Current of solar cells increases by surface-termination of Si particles.
• Incident photo-to-current conversion efficiency increases below 300 nm.

We have studied photocurrent generation in Si quantum-dot (QD) sensitized solar cells, where QD thin films composed of Si nanoparticles were deposited using the double multi-hollow discharge plasma chemical vapor deposition process in an SiH4/H2 and CH4 or N2 gas mixture. The short-circuit current density of the Si QD sensitized solar cells increases by a factor of 2.5 by using Si nanoparticles prepared by irradiation of CH4 or N2 plasma onto the Si nanoparticle surface. We have measured incident photon-to-current conversion efficiency (IPCE) in the near-ultraviolet range using quartz-glass front panels of the QD sensitized solar cells. With decreasing the wavelength of irradiation light, IPCE gradually increases upon light irradiation in a wavelength range less than about 600 nm, and then steeply increases below 300 nm, corresponding to 2.2 times the optical band-gap energy of Si QD film.