TRANSPORT, OPTICAL, AND MAGNETIC-PROPERTIES OF THE CONDUCTING HALIDE PEROVSKITE CH3NH3SNI3

A low-temperature (T less than or equal to 100 degrees C) solution technique is described for the preparation of polycrystalline and single crystal samples of the conducting halide perovskite, CH3NH3SnI3. Transport, Hall effect, magnetic, and optical properties are examined over the temperature range 1.8-300 K, confirming that this unusual conducting halide perovskite is a low carrier density p-type metal with a Hall hole density, 1/R(H)e similar or equal to 2 x 10(19) cm(-3). The resistivity of pressed pellet samples decreases with decreasing temperature with resistivity ratio rho(300 K)/rho(2 K) similar or equal to 3 and room temperature resistivity rho(300 K) similar or equal to 7 m Omega-cm. A free-carrier infrared reflectivity spectrum with a plasma edge observed at approximately 1600 cm(-1) further attests to the metallic nature of this compound and suggests a small optical effective mass, m(*) similar or equal to 0.2. (C) 1995 Academic Press, Inc.