Electroluminescent device using two dimensional semiconductor (C6H5C2H4NH3)2PbI4 as an emitter

Layered Perovskite compounds expressed by the formula (C6H5C2H4NH3)2PbX4 (X: halogen) naturally formed a dielectric quantum well structure in their spin-coated films. Strong exciton absorption and sharp photoluminescence from the exciton were observed in the spin-coated films even at room temperature; exciton absorption and emission bands of the layered Perovskite compounds were located at 3.65 eV and 3.57 eV for X=Cl, 3.08 eV and 3.05 eV for X = Br, and 2.41 eV and 2.38 eV for X = I, respectively, the combination of (C6H5C2H4NH3)2PbI4 (PhEPbI4), one of the luminescent layered Perovskite compounds, and an electron-transporting oxadiazole derivative (OXD7), a multilayered electroluminescent (EL) device consisting of indium-tin-oxide (ITO)/PhEPbI4/OXD7/MgAg was prepared. Intense EL corresponding well to the exciton emission of PhEPbI4 was observed in the device. The EL intensity was reached to luminance of about 12,000 cd m−2 at current density of 2 A cm−2 at liquid nitrogen temperature.