No abstract

To avoid formation of the photo-inactive δ-phase of formamidinium-cesium lead triiodide, copper or germanium was added to the perovskite compounds to stabilize the photoactive α-phase. It was found that the substitution of lead by germanium (Ge) or copper (Cu) provided the stabilization of the α-phase in the present work. The first-principles molecular dynamics calculations indicated that displacements of formamidinium molecules were suppressed by the Ge doping. X-ray diffraction results indicated that the Ge or Cu doping of the perovskite compounds could be effective for suppression the phase transition from α- to δ-phase.

No abstract

Fabrication and characterization of CH3NH3PbI3 perovskite solar cell with addition of copper (Cu), and potassium (K) or guanidinium (GA) was performed. Additive effects on the photovoltaic properties, morphologies and crystalline structures were investigated by the experimental results, and electronic structures and thermodynamic stabilities. The stability and conversion efficiency of the perovskite solar cells was improved by incorporating Cu at the lead site, and K or GA at the organic cation, CH₃NH₃, at A-site in cubic crystal. The simultaneous addition of Cu and K to the perovskite crystal suppressed the crystal decomposition while inhibiting desorption of MA, improving the stability of the performance.