Synthesis, characterization and phase transitions in the inorganic-organic layered perovskite-type hybrids [(CnH2n+1NH3)(2)PbI4], n=4, 5 and 6

摘要

Three inorganic-organic layered perovskite-type hybrids of the general formula [( CnH2n (+) 1NH3)(2)PbI4], n = 4, 5 and 6, display a number of reversible first-order phase transitions in the temperature range from 256 to 393 K. [( C4H9NH3)(2)PbI4] has a single phase transition, [( C5H11NH3) 2PbI4] has two phase transitions and [( C6H13NH3)(2)PbI4] has three phase transitions. In all three cases, the lowest-temperature phase transition is thermochromic and the crystals change colour from yellow in their lowest-temperature phase to orange in their higher-temperature phase for [( C4H9NH3)(2)PbI4] and [( C6H13NH3)(2)PbI4], and from orange to red for [( C5H11NH3)(2)PbI4]. The structural details associated with this phase transition have been investigated via single-crystal Xray diffraction, SC-XRD, for all three compounds.