Vibrational Properties And Exciton Phonon Interactions In Lead Sulfide Nanocrystals
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Vibrational Properties And Exciton Phonon Interactions In Lead Sulfide Nanocrystals
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Author : Todd Douglas Krauss
language : en
Publisher:
Release Date : 1998
Vibrational Properties And Exciton Phonon Interactions In Lead Sulfide Nanocrystals written by Todd Douglas Krauss and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1998 with Electron-phonon interactions categories.
Investigation Of Excitonic Properties And Hot Carrier Cooling In Lead Sulfide Quantum Dots
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Author : Eric Ronald Kennehan
language : en
Publisher:
Release Date : 2019
Investigation Of Excitonic Properties And Hot Carrier Cooling In Lead Sulfide Quantum Dots written by Eric Ronald Kennehan and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019 with categories.
Hot-carrier cooling, which has been predicted to be slowed in semiconductor quantum dots (QDs) due to the anticipated hot-phonon bottleneck, has not been readily observed, with carrier cooling rates of QDs approaching bulk cooling rates. PbS QDs are excellent potential candidates to exhibit extended hot-carrier lifetimes since confinement of both electrons and holes are nearly identical, thus circumventing an efficient Auger mechanism which has been found to increase cooling rates in other materials. Despite, the advantages of PbS QDs for enhanced hot-carrier lifetimes, rapid thermalization of hot-carriers persist in these materials and the mechanism which directs this fast cooling is not well understood. Using a combination of steady-state and time-resolve, electronic optical spectroscopy, this work has provided new insights into the behavior of excited electronic states in PbS QDs. This work identified the spectroscopic signature of the formally forbidden 1Se(h)-1De(h) intraband transition, allowing vibronic coupling to be investigated for this high energy state, along with the 1Pe(h) and band edge states. It was determined that significant homogenous broadening of these states occurs as a result of a highly size-dependent exciton-phonon coupling mechanism. It is this vibronic coupling that results in resonant energy relaxation pathways between the intraband states of the QDs that are amplified for smaller diameter nanocrystals, leading to rapid bulk-like cooling in these materials. Additionally, steady-state and time-resolved vibrational spectroscopy were used to identify possible sources of the vibronic coupling in PbS QDs. Through this work, vibrational coupling in PbS QDs, was found to be independent of the types of ligands at the crystalline surface and was in fact mediated by the surface phonons. Strong nonadiabatic coupling is occurs at the QD surface because of the broad phonon spectrum associated with the strained crystalline lattice, dangling bonds, and exposed crystal facets. This work suggests that surface modification techniques that reduce the coupling of electronic states to surface phonons may enable quantum confined structures with slower carrier cooling rates. Such surface modifications may include the use of thin inorganic shells or controlled composition gradients to reduce dangling bonds and tune the lattice strain at QD surfaces.
Excitonic And Vibrational Dynamics In Nanotechnology
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Author : Svetlana Kilina
language : en
Publisher: CRC Press
Release Date : 2019-10-10
Excitonic And Vibrational Dynamics In Nanotechnology written by Svetlana Kilina and has been published by CRC Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019-10-10 with Science categories.
The book investigates QDs and SWCNTs using quantum-chemical calculations that describe intricate details of excited-state phenomena and provides information about the mechanisms that occur on the atomic level and that are extremely difficult, if not impossible, to probe experimentally. It delivers, consistently and coherently, a novel approach to nanomaterials which is promising for today's technologies as well as their future. This approach elegantly overcomes computational difficulties known in the field and shares ways to reach top performance in the description of combined quantum effects of molecular vibrations and exciton formation on realistic-size numerical models. The reader will acquire an understanding of the pioneering methodolo
Focus On Condensed Matter Physics Research
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Author : John V. Chang
language : en
Publisher: Nova Publishers
Release Date : 2005
Focus On Condensed Matter Physics Research written by John V. Chang and has been published by Nova Publishers this book supported file pdf, txt, epub, kindle and other format this book has been release on 2005 with Science categories.
Condensed matter is one of the most active fields of physics, with a stream of discoveries in areas from superfluidity and magnetism to the optical, electronic and mechanical properties of materials such as semiconductors, polymers and carbon nanotubes. It includes the study of well-characterised solid surfaces, interfaces and nanostructures as well as studies of molecular liquids (molten salts, ionic solutions, liquid metals and semiconductors) and soft matter systems (colloidal suspensions, polymers, surfactants, foams, liquid crystals, membranes, biomolecules etc., including glasses and biological aspects of soft matter. This book presents state-of-the-art research in this exciting field.
Halide Perovskites
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Author : Tze-Chien Sum
language : en
Publisher: John Wiley & Sons
Release Date : 2019-03-25
Halide Perovskites written by Tze-Chien Sum and has been published by John Wiley & Sons this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019-03-25 with Technology & Engineering categories.
Real insight from leading experts in the field into the causes of the unique photovoltaic performance of perovskite solar cells, describing the fundamentals of perovskite materials and device architectures. The authors cover materials research and development, device fabrication and engineering methodologies, as well as current knowledge extending beyond perovskite photovoltaics, such as the novel spin physics and multiferroic properties of this family of materials. Aimed at a better and clearer understanding of the latest developments in the hybrid perovskite field, this is a must-have for material scientists, chemists, physicists and engineers entering or already working in this booming field.
Semiconductor Nanocrystal Quantum Dots
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Author : Andrey Rogach
language : en
Publisher: Springer Science & Business Media
Release Date : 2008-09-02
Semiconductor Nanocrystal Quantum Dots written by Andrey Rogach and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2008-09-02 with Technology & Engineering categories.
This is the first book to specifically focus on semiconductor nanocrystals, and address their synthesis and assembly, optical properties and spectroscopy, and potential areas of nanocrystal-based devices. The enormous potential of nanoscience to impact on industrial output is now clear. Over the next two decades, much of the science will transfer into new products and processes. One emerging area where this challenge will be very successfully met is the field of semiconductor nanocrystals. Also known as colloidal quantum dots, their unique properties have attracted much attention in the last twenty years.
Exciton Dynamics In Lead Halide Perovskite Nanocrystals
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Author : Bernhard Johann Bohn
language : en
Publisher: Springer Nature
Release Date : 2021-05-18
Exciton Dynamics In Lead Halide Perovskite Nanocrystals written by Bernhard Johann Bohn and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021-05-18 with Science categories.
Less than a decade ago, lead halide perovskite semiconductors caused a sensation: Solar cells exhibiting astonishingly high levels of efficiency. Recently, it became possible to synthesize nanocrystals of this material as well. Interestingly; simply by controlling the size and shape of these crystals, new aspects of this material literally came to light. These nanocrystals have proven to be interesting candidates for light emission. In this thesis, the recombination, dephasing and diffusion of excitons in perovskite nanocrystals is investigated using time-resolved spectroscopy. All these dynamic processes have a direct impact on the light-emitting device performance from a technology point of view. However, most importantly, the insights gained from the measurements allowed the author to modify the nanocrystals such that they emitted with an unprecedented quantum yield in the blue spectral range, resulting in the successful implementation of this material as the active layer in an LED. This represents a technological breakthrough, because efficient perovskite light emitters in this wavelength range did not exist before.
Colloidal Quantum Dot Optoelectronics And Photovoltaics
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Author : Gerasimos Konstantatos
language : en
Publisher: Cambridge University Press
Release Date : 2013-11-07
Colloidal Quantum Dot Optoelectronics And Photovoltaics written by Gerasimos Konstantatos and has been published by Cambridge University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013-11-07 with Science categories.
Captures the most up-to-date research in the field, written in an accessible style by the world's leading experts.
Physics Briefs
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Author :
language : en
Publisher:
Release Date : 1993
Physics Briefs written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1993 with Physics categories.
Materials For Sustainable Energy
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Author : Vincent Dusastre
language : en
Publisher: World Scientific
Release Date : 2011
Materials For Sustainable Energy written by Vincent Dusastre and has been published by World Scientific this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with Science categories.
The search for cleaner, cheaper, smaller and more efficient energy technologies has to a large extent been motivated by the development of new materials. The aim of this collection of articles is therefore to focus on what materials-based solutions can offer and show how the rationale design and improvement of their physical and chemical properties can lead to energy-production alternatives that have the potential to compete with existing technologies. In terms of alternative means to generate electricity that utilize renewable energy sources, the most dramatic breakthroughs for both mobile (i.e., transportation) and stationary applications are taking place in the fields of solar and fuel cells. And from an energy-storage perspective, exciting developments can be seen emerging from the fields of rechargeable batteries and hydrogen storage.