Highly Efficient Ruddlesden-Popper Halide Perovskite PA(2)MA(4)Pb(5)I(16) Solar Cells

Two-dimensional (2D) Ruddlesden-Popper (RP) organic-inorganic perovskites have emerged as promising candidates for solar cells with technologically relevant stability. Herein, a new RP perovskite, the fifth member (< n > = 5) of the (CH3(CH2)(2)NH3)(2)(CH3NH3)(n-1)PbnI3n+1 family (abbreviated as PA(2)MA(4)Pb(5)I(16)), was synthesized and systematically investigated in terms of photovoltaic application. The obtained pure PA(2)MA(4)Pb(5)I(16) crystal exhibits a direct band gap of E-g = 1.85 eV. Systematic analysis on the solid film highlights the key role of the precursor-solvent interaction in the quantum well orientation, phase purity, grain size, surface quality, and optoelectronic properties, which can be well tuned with addition of dimethyl sulfoxide (DMSO) into the N,N-dimethylformamide (DMF) precursor solution. These findings present opportunities for designing a high-quality RP film with well-controlled quantum well orientation, micrometer-sized grains, and optoelectronic properties. As a result, we achieved power conversion efficiency (PCE) up to 10.41%.