Molecular and Supramolecular Structures of Triiodides and Polyiodobismuthates of Phenylenediammonium and Its N,N-dimethyl Derivative

Despite remarkable progress in photoconversion efficiency, the toxicity of lead-based hybrid perovskites remains an important issue hindering their applications in consumer optoelectronic devices, such as solar cells, LED displays, and photodetectors. For that reason, lead-free metal halide complexes have attracted great attention as alternative optoelectronic materials. In this work, we demonstrate that reactions of two aromatic diamines with iodine in hydroiodic acid produced phenylenediammonium (PDA) and N,N-dimethyl-phenylenediammonium (DMPDA) triiodides, PDA(I-3)(2).2H(2)O and DMPDA(I-3)I, respectively. If the source of bismuth was added, they were converted into previously reported PDA(BiI4)(2).I-2 and new (DMPDA)(2)(BiI6)(I-3).2H(2)O, having band gaps of 1.45 and 1.7 eV, respectively, which are in the optimal range for efficient solar light absorbers. All four compounds presented organic-inorganic hybrids, whose supramolecular structures were based on a variety of intermolecular forces, including (N)H...I and (N)H...O hydrogen bonds as well as I...I secondary and weak interactions. Details of their molecular and supramolecular structures are discussed based on single-crystal X-ray diffraction data, thermal analysis, and Raman and optical spectroscopy.

Automated summary

This study demonstrated the synthesis of two triiodides by reacting two aromatic diamines with iodine in hydroiodic acid, which were further converted into related compounds with the addition of bismuth sources. These compounds, with band gaps suitable for efficient solar light absorption, all presented organic-inorganic hybrid structures based on a variety of intermolecular forces.