Publication date: 1st July 2014
Organometal halide perovskites have recently attracted enormous attention since MeNH3PbX3 can be successfully applied as photoactive material in photovoltaic devices, yielding solar cells with an efficiency exceeding 15%. Surprisingly, the exact mechanism how charges are generated and transported so well is unclear. In this work, we investigated the charge carrier generation, mobility and recombination in MeNH3PbI3. For MeNH3PbI3 deposited on Al2O3 we observed fast formation of microsecond lived charge carriers on pulsed laser excitation in the visible at 300 K using time resolved photoconductivity measurements with terahertz radiation or microwaves as probe. At low laser fluences a maximum charge carrier mobility of about 5 cm2/Vs, yielding charge carrier diffusion lengths well above 5 μm are found. At higher laser intensities higher order recombination processes become operative lowering the mobile charge carrier population rapidly with a rate constant of, γ= 13×10-10 cm3s-1. Reducing the temperature results in increasing charge carrier mobilities following a T-1.6 dependence, which we attribute to a reduction in phonon scattering (Σµ = 16 cm2/Vs at 165K). Despite the fact that Sµ increases on lowering the temperature, γ diminishes with a factor six implying that charge recombination in MeNH3PbI3 is temperature activated. For MeNH3PbI3 deposited on charge carrier specific electrodes, such as TiO2 and PCBM lower signal sizes are found which are explained by the rapid collection of one type of carrier by the electrode. Those collected carriers have lower mobilities leading to a reduction of signal size and, in addition to different decay kinetics. The results underline the importance of the perovskite crystal structure, the exciton binding energy and the activation energy for recombination as key factors in optimizing new perovskite materials.
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.