PREPARATION AND PROPERTIES OF(C4H9NH3)(2)EUI4 - A LUMINESCENT ORGANIC-INORGANIC PEROVSKITE WITH A DIVALENT RARE-EARTH-METAL HALIDE FRAMEWORK

(C4H9NH3)(2)EuI4 has been prepared through the low-temperature solid-s tate reaction between C4H9NH2 . HI and EuI2, providing the first examp le of a layered organic-inorganic perovskite with a divalent rare-eart h metal in the perovskite sheets. The orthorhombic lattice parameters for the new compound, a = 8.913(3) Angstrom, b = 8.759(3) Angstrom, an d c = 27.793(6) Angstrom, refined from powder X-ray diffraction data, are similar to those previously observed for the family (C4H9NH3)(2)MI 4 (M = Ge, Sn, Pb). The measured europium paramagnetic moment, 7.8(1) mu b, is consistent with the expected S-8(7/2) ground state for nomina lly isolated divalent europium ions. There is no evidence for magnetic ordering of these ions over the temperature range 1.8-300 K. Strong b lue photoluminescence is observed at 460(1) nm, a wavelength that is r ed-shifted approximately 10 nm relative to that for the more three-dim ensional perovskite structures CsEuI3 and CH3NH3EuI3. Thermal analysis indicates that, in an inert atmosphere, (C4H9NH3)(2)EuI4 undergoes bu lk decomposition at temperatures above 290 degrees C.