@article{oregan1991,
  title={A low-cost, high-efficiency solar cell based on dye-sensitized colloidal TiO2 films},
  author={Brian C. O’Regan and Michaël Grätzel},
  year={1991},
  journal={Nature},
  doi={10.1038/353737a0},
  url={https://doi.org/10.1038/353737a0}
}