Publication date: 14th January 2021
Layered hybrid organic-inorganic perovskites, such as the lead halide Ruddlesden-Popper (RP) series, are solution-processable 2D materials with tunable quantum confinement and long carrier lifetimes. 2D hybrid perovskites are formed from an ionic perovskite sub-phase (e.g. methylammonium lead iodide) and cation ‘spacer’ molecules that separate the material into layers. The soft ionic structure of layered perovskites can be influenced by static and dynamic interactions with spacer molecules, with significant impacts on optoelectronic properties relevant for device applications. In this work, dynamic motions of spacer molecules in lead iodide RP phases (n = 1) are characterized using multinuclear solid-state NMR spectroscopy at room-temperature. The site-specific rigidity of different prototypical spacers is compared using dynamic cross-polarization measurements. We find that short spacers (e.g. butylammonium and phenethylammonium) are relatively rigid near the octahedral surface, and more flexible in the interlayer. However, longer alkylammonium spacers (e.g. octylammonium and dodecylammonium) show an opposite trend, with greater rigidity deeper in the interlayer. Spacer motions observed by these measurements are too slow to couple with photogenerated carrier dynamics, but correlate with time-averaged octahedral tilting observed by XRD. These ssNMR results indicate that the interplay between spacer interactions with lead iodide octahedra (Coulombic and hydrogen-bonding) and van der Waals forces between spacers is responsible for the variety of site-specific dynamics and local structural distortions at intermediate timescales (µs-ms). This study demonstrates a general method to characterize nanoscale structures and site-specific dynamics that contribute to structural and electronic disorder in functional optoelectronic low-dimensional perovskites.
nanoGe is a prestigious brand of successful science conferences that are developed along the year in different areas of the world since 2009. Our worldwide conferences cover cutting-edge materials topics like perovskite solar cells, photovoltaics, optoelectronics, solar fuel conversion, surface science, catalysis and two-dimensional materials, among many others.
nanoGe Fall Meeting (NGFM) is a multiple symposia conference celebrated yearly and focused on a broad set of topics of advanced materials preparation, their fundamental properties, and their applications, in fields such as renewable energy, photovoltaics, lighting, semiconductor quantum dots, 2-D materials synthesis, charge carriers dynamics, microscopy and spectroscopy semiconductors fundamentals, etc.
International Conference on Hybrid and Organic Photovoltaics
International Conference on Hybrid and Organic Photovoltaics (HOPV) is celebrated yearly in May. The main topics are the development, function and modeling of materials and devices for hybrid and organic solar cells. The field is now dominated by perovskite solar cells but also other hybrid technologies, as organic solar cells, quantum dot solar cells, and dye-sensitized solar cells and their integration into devices for photoelectrochemical solar fuel production.
Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics
The main topics of the Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics (IPEROP) are discussed every year in Asia-Pacific for gathering the recent advances in the fields of material preparation, modeling and fabrication of perovskite and hybrid and organic materials. Photovoltaic devices are analyzed from fundamental physics and materials properties to a broad set of applications. The conference also covers the developments of perovskite optoelectronics, including light-emitting diodes, lasers, optical devices, nanophotonics, nonlinear optical properties, colloidal nanostructures, photophysics and light-matter coupling.
The International Conference on Perovskite Thin Film Photovoltaics Perovskite Photonics and Optoelectronics (NIPHO) is the best place to hear the latest developments in perovskite solar cells as well as on recent advances in the fields of perovskite light-emitting diodes, lasers, optical devices, nanophotonics, nonlinear optical properties, colloidal nanostructures, photophysics and light-matter coupling.