Improved solar cell efficiency (and improved cost of manufacture) is one of the most critical factors in further developing solar energy. Experimenting with perovskite solar cells (perovskites are compounds with a crystal structure that follows the form of naturally-occurring calcium titanium trioxide (CaTiO₃) even when using other elements) has produced more efficient solar cells.

Now, researchers from Henan University in China have manufactured titanium dioxide (TiO₂) perovskite solar cells doped with nitrogen, and found a “sweet spot” with how much nitrogen to use that optimizes their results.

What Zhen-Long Zhang, Jun-Feng Li, Xiao-Li Wang, Jian-Qiang Qin, Wen-Jia Shi, Yue-Feng Liu, Hui-Ping Gao, and Yan-Li Mao found was that by doping their titanium dioxide with 1% by atomic weight nitrogen, that they increased the power conversion by 14.7%.

To find out why, they examined the material with X-ray powder diffraction and scanning electron microscopy. They found that the doped solar cells absorbed more light than undoped cells, and also that the doped cells had a lower energy band gap than undoped cells. They hypothesize that these changes caused the increased energy conversion efficiency.

You can read the entire study, published earlier this month in Nanoscale Research Letters, here: Enhancement of Perovskite Solar Cells Efficiency using N-Doped TiO₂ Nanorod Arrays as Electron Transfer Layer