Excitons in self-organized layered perovskite films prepared by the two-step growth process

Thin films of microcrystalline (C8H17NH3)(2)PbBr4 were prepared by a two-step growth process as follows: (1) deposition of PbBr2 films on substrates and (2) self-organized growth of layered perovskite compounds by exposing the PbBr2 film to C8Hl7NH3Br vapor in a vacuum chamber. As-synthesized (C8H17NH3)(2)PbBr4 films were characterized by using X-ray diffraction, temperature dependence in optical absorption and photo luminescence spectra. (C8H17NH3)(2)PbBr4 films created by this synthesis approach were found to microcrystalline form, single phase and highly oriented with a c-axis perpendicular to the substrate surface. (C8H17NH3)(2)PbBr4 films showed clear exciton absorption and photoluminescence even at room temperature in the near-ultraviolet region. Exciton binding energy of (C8H17NH3)(2)PbBr4 was estimated about 200 meV. (c) 2005 Elsevier B.V. All rights reserved.