Synthesis and Characterization of Imidazole-based Organic-Inorganic Perovskites

Abstract

Organic-inorganic perovskites (OIPs) are hybrid materials which contain cationic organic molecules in the lattice. Compared to conventional perovskites, solution-based processing is possible for OIPs to coat on various substrates easily with low cost. Nowadays, OIPs are receiving extensive attention because of its high efficiency as photosensitizer in solid-state solar cells. However, most of researches related with OIPs photosensitizer are only focused on methyl ammonium lead iodide (MPI) which possesses short alkyl chain with primary amine. In other words, there are only limited variables that can change its properties. This makes further improvements of MPI difficult. Moreover, MPI has low stability under high humidity. Here, we successfully synthesized new imidazole-based OIPs using biomolecules, histidine and histamine. In addition, we confirmed that our new perovskites can be applied as photosensitizer in solid-state solar cells. For materials characterization, single crystal structure analysis, band structure analysis, and thermal stability test were conducted. As a result, we verified detailed crystallographic structure, and band position. To optimize the solar cell properties, we also optimized conditions with one-step spin-coating and two-step dip coating. This research has three major impacts. First of all, we show the possibility that not only the primary amine, but also the whole imidazole group can be involved in inorganic layer. It is worth noting that the tuning of OIPs properties is possible by different types of organic molecules and functional groups. Secondly, we suggest the new point of convergence with biomolecules and inorganic materials through synthesized new hybrid materials. Thirdly, we confirm that our OIPs are relatively endurable in humid conditions than MPI. Successful improvement on water-resistance, however, is an essential requirement for the commercialization of OIPs-based solid-state solar cells.