Materials, Methods & Technologies, Volume 12, 2018

Abstract: Flexible high efficiency solar cells with an active layer of organometallic perovskite material with CH3NH3+ organic cation surrounded by metal halide MX6 (M=Pb or Sn, X=I, Br or Cl) octahedron structures is extraordinarily promising as efficient light absorbers since their controllable bandgap ranging from 1.5-2.3 eV corresponding to the optimal solar absorption band. Modification of the bandgap is possible with the precise adjustment of halide concentration. Theoretically this allows the material to have very high solar conversion efficiencies of detailed balance or so called the Shockley-Queisser limit of around 31%. Most recently reported efficiencies are around 20%. However reliable and repeatable devices are reported to have around 12-18% efficiencies. The popular challenge is that what makes a proper process, combination and design to have very high solar conversion efficiencies up to 31%. In this study we will introduce a comparative review of present studies in order to find out an optimal conditions to reach higher efficiencies in perovskite solar cells in terms of various aspects such as processing, chemical combination and device modeling. In particular, we introduce a unique spin coating process named dual coating combining the static and dynamic coating processes, giving rise to repeatable and stable power conversion efficiencies of around 15% at a beginning stage in research laboratory conditions.