Preparation and characterization of a layered perovskite-type organic–inorganic hybrid compound based on (C6H4)2N (CH2)6NH3Cl

The organic–inorganic hybrid compound ((C6H4)2N(CH2)6NH3)2PbCl4 (N6AHMC–PbCl4) and ((C6H4)2N(CH2)6NH3)2PbCl2I2 (N6AHMC–PbCl2I2) were synthesized by treating N-6-aminohexamethylcarbazole chloride (N6AHMC–HCl) with stoichiometric amount of PbX2 (X = Cl, I) at room temperature using dimethylformamide (DMF) as solution. High order diffraction peaks corresponding to (0 0 l) (l = 2, 4, 6, …) were observed in the X-ray diffraction profile of N6AHMC–PbCl4 and N6AHMC–PbCl2I2, indicating the formation of hybrid crystal with layered perovskite structure. N6AHMC–PbCl4 presented characteristic absorptions of PbCl-based layered perovskite centered at about 329 nm. Similar to the PL spectrum of N6AHMC–HCl, the film of N6AHMC–PbCl4 showed three strong emission peaks, indicating that the exciton emission of the N6AHMC–PbCl4 film comes from the organic layer of the hybrids. Owing to the partially replacement of Cl− with I−, the fluorescence quenched N6AHMC–PbCl2I2 showed broad absorption at about 400 nm, which is assigned to the transition from the hybrid orbital hybridized by Cl 3p and I 5p valence states to Pb 6p conduction bands. For the reason of the variation of the energy band structure, from type I quantum well structure to type II heterojunction, the photoconductivity of N6AHMC–PbCl2I2 is higher than that of N6AHMC–PbCl4.