DOI: https://doi.org/10.29363/nanoge.hpatom.2022.022
Publication date: 30th October 2021
Broadband light emission has been observed in some layered inorganic-organic halide semiconductors perovskite derivatives. This behavior correlates strongly with static structural distortions corresponding to out-of-plane tilting of the lead halide octahedra. While materials with different organic cations can yield distinct out-of-plane tilts, the underlying origin of the octahedral tilting remains poorly understood. From the analysis of high energy resolution (e.g., quasi-elastic) neutron scattering, a larger spatial extent of rotational dynamics of the organic cations in A2PbBr4 materials yields a larger effective cation radius and prevents the out-of-plane tilt and broadband luminescence. Furthermore, the organic cation dynamics are attributed to rotation of the ammonium head group and occur at a timescale faster than the white light photoluminescence studied by time-correlated single photon counting spectroscopy. This supports a previous assignment of the broadband emission as resulting from a single ensemble, such that the emissive excited state experiences many local structures faster than the emissive decay. The findings presented here highlight the role of the organic cation and its dynamics in hybrid organic-inorganic perovskites and white light emission.
The work at Colorado State University was supported by grant DE-SC0016083 funded by the U.S. Department of Energy, Office of Science. J.R.N. and A.A.K. acknowledge support from Research Corporation for Science Advancement through a Cottrell Scholar Award, and J.R.N. thanks the A.P. Sloan Foundation for assistance provided from a Sloan Research Fellowship. A portion of this research used resources at the Center for Neutron Research, operated by the National Institute of Standards and Technology (NIST) and the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. Access to the High Flux Backscattering Spectrometer was provided by the Center for High Resolution Neutron Scattering, a partnership between the National Institute of Standards and Technology and the National Science Foundation under Agreement No. DMR-2010792. The computing resources for the QENS calculations were made available through the ICEMAN project, funded by the Laboratory Directed Research and Development program at Oak Ridge National Laboratory. The authors wish to thank the Analytical Resources Core at Colorado State University for instrument access, training and assistance with sample analysis.
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.
Previously nanoGe Spring Meeting (NSM) and nanoGe Fall Meeting (NFM), MATSUS is a multiple symposia conference 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.