In this work, we demonstrate that 1D EDPbI4 crystals containing face-sharing PbI64− octahedra are synthesized using ethylenediammonium (ED) as an organic cation in hydroiodic acid. However, by the addition of… Click to show full abstract
In this work, we demonstrate that 1D EDPbI4 crystals containing face-sharing PbI64− octahedra are synthesized using ethylenediammonium (ED) as an organic cation in hydroiodic acid. However, by the addition of hydrochloric acid to the synthetic solution, 2D [(ED)2PbI4]Cl2 crystals are interestingly constructed without substitution of iodides by chlorides. The importance of chloride ions in the structure has been revealed by employing the single-crystal X-ray diffraction technique. Isolated chlorides, through forming hydrogen bonds with ammonium groups and creating (ED)2Cl22+ templating layers, lessen the interplays between organic cations and inorganic units and consequently lead to the formation of almost undistorted PbI42− perovskite layers. The band gaps of the resultant crystals have been determined to be 2.72 eV and 2.30 eV for EDPbI4 and [(ED)2PbI4]Cl2, respectively. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) measurements indicate that both compounds are thermally stable up to 250 °C without any phase transition.
               
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