Low Dimensional Organometal Halide Perovskites

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Non-technical Description. New functional materials are one of the keys to the advance of technologies useful in our daily life. Organometal halide perovskites are an emerging class of organic-inorganic hybrid materials that have potential applications in many optoelectronic devices, such as solar cells and light emitting diodes. In this project, the research team aims to develop and study new types of organometal halide perovskites with unique crystalline structures and properties that have not been observed in conventional ones. Of particular interest are low dimensional organometal halide perovskites that have been largely unexplored by the research community. The expected outcomes of this project include fundamental understandings of this new class of materials, and guidelines for the development of functional materials with new phenomena and superior performance for optoelectronic devices. Various educational and outreach activities are integrated in this project, including: (i) promoting multidisciplinary research, education and training to graduates and undergraduate students, in particular those from underrepresented groups; (ii) involving K-12 students and general public through scientific exhibitions of "The Evolution of Lighting Technology at the Challenger Learning Center of Tallahassee. Technical Description. Organometal halide perovskites are crystalline hybrid materials with exceptional structural tunability. By choosing appropriate inorganic and organic components, the crystallographic structures can be finely controlled with the inorganic units, metal halide octahedrons, forming zero- (0D), one- (1D), two- (2D), and three-dimensional (3D) structures in the hybrids on molecular level. Despite a great deal of work conducted in this class of materials, the research focus to date has been mainly on 3D and 2D perovskites, with little done in 1D and 0D perovskites that can exhibit unique, remarkable and useful properties significantly different from those of 3D and 2D perovskites. In this project, the research team investigates new low dimensional organometal halide perovskites with 1D and 0D structures, in which the metal halide octahedrons are connected in a chain (1D) and completely isolated from each other (0D), respectively. The research involves (i) identification and understanding of phenomena and mechanisms associated with synthesis and processing of 1D and 0D perovskites, (ii) characterization of the unique structural, optical, and electronic properties of these new materials to gain a fundamental understanding of the structure-property relationship, and (iii) investigation of their functionalities in optoelectronic devices, such as optically pumped and electrically driven light emitting diodes. The success of this project can generate guidelines for the development of new organic-inorganic hybrid materials to exhibit novel phenomena and superior performance in optoelectronic devices. The knowledge gained in this project can relate the classic molecular science to solid-state physics, for instance "excited state structural distortion" in molecular concept to "exciton self-trapping" in solid state theory, as the building blocks of these materials can be considered as either molecular species or lattice points.