Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV18)
Publication date: 21st February 2018
Three polycyclic aromatic cations, 2-ammonium fluorene (AF), 2-ammonium anthracene (AA) and 2,7-diamonium fluorene (DAF) are successfully assembled with inorganic PbBr6 octahedra to synthesize the (AF/AA)2PbBr4 and (DAF)PbBr4 one-dimensional (1D) hybrid perovskites. The synthesis of the perovskites is performed via an environmentally-friendly mechanochemical approach involving a solid-state solventless reaction. The analysis of the X-ray powder diffraction (XRD) data revealed the crystal structure of these materials consisting of quasi-linear wires of PbBr42- separated by polycyclic cations with alternating positions of NH3+ groups. DFT calculations have shown a remarkable contribution of the orbitals of the 2-ammonium fluorene to both the valence band maximum (VBM) and conduction band minimum (CBM) of the (AF)2PbBr4 structure. Moreover, the same hybrid materials were effectively prepared as thin films by using the spin-coating method from a solution containing the precursors. Although these hybrid perovskites are not intrinsically emissive, the strong fluorescence signal from the organic cation is preserved.