Researchers at Edo University (Nigeria) and University of Bening (Nigeria) recently worked together to investigate the electronic and optical properties of nitrogen doped anatase for solar power applications. Anatase is one of the prominent polymorphs of Titanium dioxide (TiO2) and has great potential for solar applications. The only issue is the wide band gap which limits its solar energy utilization to only 4%. A lot of research has been done on anatase over the years due to its availability and low cost.
One proposed method to increasing the effectiveness of anatase in solar applications is through doping. In this context, doping is the intentional introduction of impurities for the purpose of modulating its electrical, optical and structural properties. Electronic and optical properties are presented here for pure and Nitrogen (N) doped anatase. The study is based on the density functional theory (DFT) using generalized gradient approximation (GGA) in addition to Coulomb Interaction (U) as implemented in quantum espresso code while the optical properties calculation was done with the Yambo code. With the inclusion of U parameter of 12.5eV, band gap of 3.1eV was obtained which compared favorably with experimental results. Doping concentration of 3.1% gave rise to band narrowing while Partial density of state (PDOS) shows that the band narrowing in anatase is due to the contribution from 2p state of the Nitrogen dopant. The optical properties calculated revealed that N-doped anatase has optical crests in the visible light range of electromagnetic spectrum which makes it a potential material for solar application with higher efficiency than pure anatase.
Solar energy has a lot of potential in Africa, the main barrier to widespread solar adoption is still the high cost of installing solar energy systems. As research continues we hope that new efficiencies continue to be found and prices will come down further in time.