Enhancing electron transport in perovskite solar cells by incorporating GO to the meso-structured TiO2 layer

In this study, the graphene oxide (GO)-TiO2 nanocomposite film prepared by the sol-gel method was used to optimize the photoelectric performance of the perovskite solar cells (PSCs), which structure is based on the carbon electrode and no hole transport layer. Through a series of scientific experiments, it has been proved that the GO-TiO2 nanocomposite film has excellent electrical properties. The electron transport layer which containing 1 wt% of GO makes the PSCs have the most excellent performance. Compared with the controlling PSCs, the photoelectric conversion efficiency of PSCs, which containing 1 wt% GO, increased by 9.3%, from 12.44 to 13.60%. Short-circuit current density (Jsc) increased by 5.99%, from 21.55 to 22.84 mA/cm(2), and open circuit voltage remained basically unchanged. It can be seen from the measurement results that the trend of incident photon-to-electron conversion efficiency spectrum is consistent with J-V characteristics, indicating that the PSCs device containing 1 wt% GO has the best electron extraction and transfer performance. However, when too much GO is used, the increased surface charge trap state will lead to the acceleration of carrier recombination and the decrease of electron transport path, and the photovoltaic parameters show a downward trend.