(110)-Oriented Asymmetric Phenylene Diammonium-Based Quasi-Two-Dimensional Perovskites for Solar Cell Applications

There is growing interest in developing perovskite solar cells (PSCs) using quasi-two-dimensional (q-2D) Pb-based perovskite compounds that show higher stability than three-dimensional (3D) perovskite compounds. To achieve high power conversion efficiency by using q-2D perovskite compounds as a photoabsorber for PSCs, the conducting perovskite layers must orient in a favorable direction for carrier transport. Four types of organic amine, N,N-dimethyl-1,3-dipropanediamine, N,N-dimethyl-p-phenylenediamine, butylamine, and 1,4-butanediamine, were used with the combination of different solvents and temperature conditions. From this consideration, we developed q-2D perovskite films adopting asymmetric phenylene diammonium that exhibited (110) orientation in the presence of dimethyl sulfoxide as a solvent for the first time. The crystal growth proceeded via an intermediate phase that was oriented 45° to the substrate. A competitive relationship was developed between crystal growth and solvent vaporization using large cations and solvent engineering.