Perovskite solar cells using TiO2 layers coated with metal-organic framework material ZIF-8

A metal-organic framework of ZIF-8 is used as an interlayer between the mesoporous TiO2 and the perovskite layer in perovskite solar cells (PSCs). The ZIF-8 solution is dried on the mesoporous TiO2 layer, which can then act as an additional light absorbing layer at the short-wavelength range for the solar cells, leading to improved performance of the cell. After an immersion time of 1-5 min, a very thin ZIF-8 film is formed on TiO2. An enhancement in the incident photon to current conversion efficiency (IPCE) is achieved for PSCs using the ZIF-8-coated TiO2 layer. The conversion efficiency of PSCs is improved from 9.6 to 12.0% when ZIF-8 is present. UV-vis and photoluminescence (PL) spectra are used to investigate the beneficial effect of ZIF-8/TiO2 hybrid layers.