Peng Qin1

1, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, , China

As a promising candidate for the low cost photovoltaic technology, perovskite solar cells (PSCs) have been intensively investigated since the first report by Miyasaka et al. in 2009. Tremendous efforts have been made in the investigation of crystal growth and intrinsic properties of perovskites, as well as the improvement of device performance and stability. The latest certified power conversion efficiencies (PCEs) of small-area perovskite solar cells have been reported to be 22.1%, approaching those of the commercial polycrystalline silicon, CdTe, and CIGS solar cells.

The well-known organic-inorganic hybrid perovskite MAPbI3 suffers from a spontaneous tetragonal to cubic phase transition at 54°C, which could lead to undesired lattice strain and distortion during device operation. Here we demonstrate the design and synthesis of thermal-stable cubic perovskite semiconductors at room temperature through the incorporation of larger organic cation. Single crystals with different ratio of the organic cations are prepared, and the X-ray diffraction spectra reveal the formation of cubic phase. The nonradiative recombination in the prepared cubic perovksite semiconductors is suppressed. The more efficient charge extraction leads to an improvement in the photocurrent density, and then the device performance.

Besides the organic-inorganic hybrid perovskites, the cubic lead free double perovskite system is investigated. The influence of structural configuration on the optical properties, charge extraction, as well as the photovoltaic performance are systematically investigated, which offers a new strategy for the preparation of environmentally-friendly perovskite semiconductors.