Synthesis, structure, and photovoltaic property of a nanocrystalline 2H perovskite-type novel sensitizer (CH(3)CH(2)NH(3))PbI(3)

A new nanocrystalline sensitizer with the chemical formula (CH(3)CH(2)NH(3))PbI(3) is synthesized by reacting ethylammonium iodide with lead iodide, and its crystal structure and photovoltaic property are investigated. X-ray diffraction analysis confirms orthorhombic crystal phase with a = 8.7419(2) Å, b = 8.14745(10) Å, and c = 30.3096(6) Å, which can be described as 2 H perovskite structure. Ultraviolet photoelectron spectroscopy and UV-visible spectroscopy determine the valence band position at 5.6 eV versus vacuum and the optical bandgap of ca. 2.2 eV. A spin coating of the CH(3)CH(2)NH(3)I and PbI(2) mixed solution on a TiO(2) film yields ca. 1.8-nm-diameter (CH(3)CH(2)NH(3))PbI(3) dots on the TiO(2) surface. The (CH(3)CH(2)NH(3))PbI(3)-sensitized solar cell with iodide-based redox electrolyte demonstrates the conversion efficiency of 2.4% under AM 1.5 G one sun (100 mW/cm(2)) illumination.