New design of potentially low-cost solar cells using TiO2/graphite composite as photon absorber

We propose a solar cell design using the combination of titanium dioxide (TiO2) and graphite as active photon absorbing materials. TiO2 absorbs photons of nearly ultraviolet wavelengths to produce electron–hole pairs, while graphite is expected to absorb photons of longer wavelengths. Although many authors have claimed that graphite is a semimetal, we observed that a model of a solar cell containing TiO2 only as the active material behaves exactly the same as a model containing graphite only as the active material. Additionally, we observed that a model of a solar cell made using a composite of TiO2 and graphite as the active material had much higher efficiency than solar cells made using TiO2- or graphite-only active materials. Although the highest efficiency we report here is approximately 1 %, our proposed solar cell structure is promising for mass application, especially in low-income settings, owing to its easy and flexible fabrication, and easy large-scale application.