Enhancement of Perovskite Solar Cells by TiO(2)-Carbon Dot Electron Transport Film Layers

The high performance of perovskite solar cells was produced with the help of an electron transport layer (ETL) and hole transport layer. The film ETL (mesoporous (meso)-TiO(2)/carbon dot) boosted the efficiency of the perovskite solar cells. A perovskite cell was fabricated by a coating of carbon dot on a meso-TiO(2) ETL. The fabricated meso-TiO(2)/carbon dot-based device has decreased the pin-holes of the perovskite film layer compared to the meso-TiO(2)-based device, which boosted 3% of the averaged PCE value of the devices. The UV–visible spectroscopy confirmed that the meso-TiO(2)/carbon dot ETL showed better absorbance, that is, absorbed more incident light than meso-TiO(2) ETL to generate higher power conversion efficiency. Coating of carbon dot on meso-TiO(2) reduced carrier recombination, and fadeaway of the perovskite film cracks. The X-ray diffraction spectra displayed the removal of the perovskite component after spin-coating of carbon dot to the meso-TiO(2) ETL, indicating that the suppression of non-radiative recombination improves the device performance compared to meso-TiO(2) ETL. The stability after four weeks on the performance of the device was improved to be 92% by depositing carbon dot on meso-TiO(2) ETL compared to the meso-TiO(2) ETL-based device (82%). Thus, the high-quality perovskite cell was fabricated by coating carbon dot on a meso-TiO(2) ETL, because the electron transport between ETL and perovskite film layer was improved by the injection of electrons from carbon dot.