We have fabricated a series of potassium-doped (K-doped) perovskite solar cells (PSCs). Structural investigations of the developed PSCs have shown that alkai doping affects the perovskite layer structure and morphology with the increase of the crystallite size and surface uniformity. K-doped samples exhibite higher PV performance and improved operational stability compared to the control series of undoped PSCs, due to retarded recombination processes.

New types of two-terminal tandem solar cells DSC/ c -Si in which mesoscopic dye-sensitized solar cell (DSC) was connected in parallel with a crystalline silicon ( c -Si) solar cell, were developed and investigated. We have measured the optical and photovoltaic parameters for both the individual and the fabricated tandem DSC/ c -Si solar cells. It was shown that the highest efficiency of 14.7% for the tandem DSC/ c -Si solar cell under standard AM1.5G (100 mW/cm^2) illumination conditions was achieved for DSC based on 3.5 μm thick titanium dioxide photoelectrode.