College
College of Arts & Sciences
Mentor Information
Ioannis Spanopoulos
Description
2D metal halide semiconductors are of great interest for increasing photovoltaic efficiency in solar cells and light emitting diodes. Here, we synthesized materials to investigate the mechanical and thermal stability of Metal Halide Perovskites (MHPs) as a function of the Pb—X bond, n-layer thickness, and carbon chain length of the organic linkers, which are known to affect the in- and out-of-plane mechanical properties of 2D materials.
To assess the mechanical properties of 2D MHPs at differing thicknesses and linker lengths, we synthesized pure-phase (BA)2(MA)2Pb3Br10, (HA)2(MA)Pb2Br7, and (OA)2(MA)Pb2Br7 for single crystal Brillouin scattering spectroscopy. Optimization of reaction conditions was necessary, because existing literature protocols gave mixed-phases or no yield. We observed that annealing to lower temperatures resulted in increasing extraneous peaks on the Powder X-Ray Diffractometer (PXRD), indicating the formation of undesired lower n-value phase crystals. By optimizing synthesis protocols, we established reproducible procedures for the isolation of pure-phase(BA)2(MA)2Pb3Br10, (HA)2(MA)Pb2Br7, and (OA)2(MA)Pb2Br7 . Ongoing single crystal Brillouin scattering spectroscopy will determine properties of 2D metal halide semiconductors that affect their mechanical robustness and overall stability.
Synthesis Optimization of Ruddlesden-Popper Metal Halide Semiconductors
2D metal halide semiconductors are of great interest for increasing photovoltaic efficiency in solar cells and light emitting diodes. Here, we synthesized materials to investigate the mechanical and thermal stability of Metal Halide Perovskites (MHPs) as a function of the Pb—X bond, n-layer thickness, and carbon chain length of the organic linkers, which are known to affect the in- and out-of-plane mechanical properties of 2D materials.
To assess the mechanical properties of 2D MHPs at differing thicknesses and linker lengths, we synthesized pure-phase (BA)2(MA)2Pb3Br10, (HA)2(MA)Pb2Br7, and (OA)2(MA)Pb2Br7 for single crystal Brillouin scattering spectroscopy. Optimization of reaction conditions was necessary, because existing literature protocols gave mixed-phases or no yield. We observed that annealing to lower temperatures resulted in increasing extraneous peaks on the Powder X-Ray Diffractometer (PXRD), indicating the formation of undesired lower n-value phase crystals. By optimizing synthesis protocols, we established reproducible procedures for the isolation of pure-phase(BA)2(MA)2Pb3Br10, (HA)2(MA)Pb2Br7, and (OA)2(MA)Pb2Br7 . Ongoing single crystal Brillouin scattering spectroscopy will determine properties of 2D metal halide semiconductors that affect their mechanical robustness and overall stability.
