Investigating the feasibility of symmetric guanidinium based plumbate perovskites in prototype solar cell devices

In this work we have studied the feasibility of highly symmetric guanidinium (GA; CH6N3+) cation in perovskite based solar cells. It is an alternative to the methyl ammonium (MA; CH3NH3+) or formamidinium (FA; CH(NH2)(2+)) ions commonly utilized in the perovskite solar cells, may bring additional advantages due to its triad rotational symmetry and zero dipole moment (mu). We noticed that due to steric factors, GA preferably forms two-dimensional (2D) layer, where GA(2)PbI(4) is favored monoclinic structure (E-g = 2.5 eV) and the obtained device efficiency is eta = 0.45%. This study provides a guideline for designing guanidinium based perovskite absorbers for solar cell devices. In addition, through further compositional engineering with mixed organic cations using GA may enhance the device performance. (C) 2017 The Japan Society of Applied Physics