Download or read book Optical Study of Quantum Dot and Perovskite Light emitting Diodes Based on Simulation written by 梅冠鼎 and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Quantum dot Based Light emitting Diodes written by Morteza Sasani Ghamsari and published by BoD – Books on Demand. This book was released on 2017-10-25 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum dot-based light emitting diodes were assigned to bringing together the latest and most important progresses in light emitting diode (LED) technologies. In addition, they were dedicated to gain the perspective of LED technology for all of its advancements and innovations due to the employment of semiconductor nanocrystals. Highly selective, the primary aim was to provide a visual source for high-urgency work that will define the future directions relating to the organic light emitting diode (OLED), with the expectation for lasting scientific and technological impact. The editor hopes that the chapters verify the realization of the mentioned aims that have been considered for editing of this book. Due to the rapidly growing OLED technology, we wish this book to be useful for any progress that can be achieved in future.
Download or read book Colloidal Quantum Dot Light Emitting Diodes written by Hong Meng and published by John Wiley & Sons. This book was released on 2024-02-20 with total page 405 pages. Available in PDF, EPUB and Kindle. Book excerpt: Explore all the core components for the commercialization of quantum dot light emitting diodes Quantum dot light emitting diodes (QDLEDs) are a technology with the potential to revolutionize solid-state lighting and displays. Due to the many applications of semiconductor nanocrystals, of which QDLEDs are an example, they also hold the potential to be adapted into other emerging semiconducting technologies. As a result, it is critical that the next generation of engineers and materials scientists understand these diodes and their latest developments. Colloidal Quantum Dot Light Emitting Diodes: Materials and Devices offers a comprehensive introduction to this subject and its most recent research advancements. Beginning with a summary of the theoretical foundations and the basic methods for chemically synthesizing colloidal semiconductor quantum dots, it identifies existing and future applications for these groundbreaking technologies. The result is tailored to produce a thorough understanding of this area of research. Colloidal Quantum Dot Light Emitting Diodes readers will also find: An author with decades of experience in the field of organic electronics Detailed discussion of topics including advanced display technologies, the patent portfolio and commercial considerations, and more Strategies and design techniques for improving device performance Colloidal Quantum Dot Light Emitting Diodes is ideal for material scientists, electronics engineers, inorganic and solid-state chemists, solid-state and semiconductor physicists, photochemists, and surface chemists, as well as the libraries that support these professionals.
Download or read book Quantum Dot Optoelectronic Devices written by Peng Yu and published by Springer Nature. This book was released on 2020-04-16 with total page 329 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book captures cutting-edge research in semiconductor quantum dot devices, discussing preparation methods and properties, and providing a comprehensive overview of their optoelectronic applications. Quantum dots (QDs), with particle sizes in the nanometer range, have unique electronic and optical properties. They have the potential to open an avenue for next-generation optoelectronic methods and devices, such as lasers, biomarker assays, field effect transistors, LEDs, photodetectors, and solar concentrators. By bringing together leaders in the various application areas, this book is both a comprehensive introduction to different kinds of QDs with unique physical properties as well as their preparation routes, and a platform for knowledge sharing and dissemination of the latest advances in a novel area of nanotechnology.
Download or read book Charge and Exciton Dynamics in Quantum Dot Light emitting Diodes written by Han Zhu (Ph. D.) and published by . This book was released on 2019 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: Colloidal quantum dot based light-emitting diodes (QD-LEDs) offer the possibility of bright, saturated, and tunable emission for the next generation of display and solid state lighting technologies. In this thesis, we study how the interplay of charges and excitons in a QD-LED affect its operational behavior. In order to construct a physical model of a QD-LED, we start by developing quantitative characterization methods that directly measure charge accumulation and electric field in an operating device. Comparison of measured internal device variables with observed electroluminescence and current density allows us to disentangle the deleterious effects of charge imbalance, electric field, and Joule heating on the external quantum efficiency. We also find that the magnitude of electron accumulation on the QD film is sensitive to its interface with the neighboring hole transport layer (HTL) and can reach nearly one electron per QD even in the best performing device. We next investigate how exciton formation is affected by the high charge density. Since the degree of electron charging of a nanocrystal shifts the energy barrier for hole injection, the kinetics of exciton formation are dependent on electron occupation statistics on the QD film. Using kinetic Monte Carlo simulations that explicitly incorporate both long and short range Coulomb interactions, we find that energetic disorder of the QD film strongly enhances the formation of negatively charged excitons by increasing the population of two-electron occupied QDs. Finally, we demonstrate that the photoluminescence yield of a QD film can be intentionally quenched by up to 99.5% in a QD-LED under reverse bias. This paves the way for a voltage-tuned optical down-conversion device using colloidal QDs.
Download or read book Perovskite Quantum Dots written by Ye Zhou and published by Springer Nature. This book was released on 2020-08-27 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book addresses perovskite quantum dots, discussing their unique properties, synthesis, and applications in nanoscale optoelectronic and photonic devices, as well as the challenges and possible solutions in the context of device design and the prospects for commercial applications. It particularly focuses on the luminescent properties, which differ from those of the corresponding quantum dots materials, such as multicolor emission, fluorescence narrowing, and tunable and switchable emissions from doped nanostructures. The book first describes the characterization and fabrication of perovskite quantum dots. It also provides detailed methods for analyzing the electrical and optical properties, and demonstrates promising applications of perovskite quantum dots. Furthermore, it presents a series of optoelectronic and photonic devices based on functional perovskite quantum dots, and explains the incorporation of perovskite quantum dots in semiconductor devices and their effect of the performance. It also explores the challenges related to optoelectronic devices, as well as possible strategies to promote their commercialization. As such, this book is a valuable resource for graduate students and researchers in the field of solid-state materials and electronics wanting to gain a better understanding of the characteristics of quantum dots, and the fundamental optoelectronic properties and operation mechanisms of the latest perovskite quantum dot-based devices.
Download or read book Colloidal Quantum Dot Optoelectronics and Photovoltaics written by Gerasimos Konstantatos and published by Cambridge University Press. This book was released on 2013-11-07 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt: Capturing the most up-to-date research in colloidal quantum dot (CQD) devices, this book is written in an accessible style by the world's leading experts. The application of CQDs in solar cells, photodetectors and light-emitting diodes (LEDs) has developed rapidly over recent years, promising to transform the future of clean energy, communications, and displays. This complete guide to the field provides researchers, students and practitioners alike with everything they need to understand these developments and begin contributing to future applications. Introductory chapters summarise the fundamental physics and chemistry, whilst later chapters review the developments that have propelled the field forwards, systematically working through key device advances. The science of CQD films is explained through the latest physical models of semiconductor transport, trapping and recombination, whilst the engineering of organic and inorganic multilayered materials is shown to have enabled major advances in the brightness and efficiency of CQD LEDs.
Download or read book Development of Colloidal Quantum Dot and Lead Halide Perovskite Light Emitting Devices written by Sihan Xie (Ph. D.) and published by . This book was released on 2021 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years, optically active semiconductors, such as organic molecules, colloidal quantum dots (QDs) and lead halide perovskites, have emerged as top candidates for light emitting materials. One key feature of these materials is their bandgap tunability, e.g. via size or chemical composition, allowing for their emission color to be turned throughout the entire visible spectrum. Thin-film light emitting devices (LEDs) based on these luminophores are promised to deliver the next-generation display technologies that are ultrathin and light, high-color-quality, and energy efficient with new form factors (e.g. foldable and flexible). In this thesis, we present the work performed to improve the understanding and performance of colloidal nanocrystal QDs and lead halide perovskites as visible luminophores in optically- and electrically-driven thin-film LEDs. First, we create an efficient voltage-controlled optical down-converter by operating a quantum dot light emitting diode (QD-LED) under reverse bias. Using field-induced luminescence quenching to our advantage, we show that a large electric field can strongly modify QD carrier dynamics, resulting in stable and reversible QD photoluminescence (PL) modulation. Next, we address the QD’s toxicity issue by developing a synthesis of heavy-metal-free ZnSe/ZnS core-shell QDs with narrow spectral linewidth and high PL quantum yield. By employing these QDs as emitters, we demonstrate QD-LEDs with efficient and saturated blue electroluminescence (EL). Finally, we present a new way of depositing compact CsPbBr3 perovskite thin films by thermal co-evaporation and demonstrate all vacuum-processed perovskite LEDs with efficient green EL emission. Our results show that evaporative deposition can be a viable alternative to solution-based deposition for fabricating high-quality perovskite thin films for LEDs.
Download or read book Light emitting Diodes written by Huade Walter Yao and published by SPIE-International Society for Optical Engineering. This book was released on 2004 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of SPIE present the original research papers presented at SPIE conferences and other high-quality conferences in the broad-ranging fields of optics and photonics. These books provide prompt access to the latest innovations in research and technology in their respective fields. Proceedings of SPIE are among the most cited references in patent literature.
Download or read book Silicon Light Emitting Diodes and Lasers written by Motoichi Ohtsu and published by Springer. This book was released on 2016-07-28 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on a novel phenomenon named photon breeding. It is applied to realizing light-emitting diodes and lasers made of indirect-transition-type silicon bulk crystals in which the light-emission principle is based on dressed photons. After presenting physical pictures of dressed photons and dressed-photon phonons, the principle of light emission by using dressed-photon phonons is reviewed. A novel phenomenon named photon breeding is also reviewed. Next, the fabrication and operation of light emitting diodes and lasers are described The role of coherent phonons in these devices is discussed. Finally, light-emitting diodes using other relevant crystals are described and other relevant devices are also reviewed.
Download or read book Characterization Techniques for Perovskite Solar Cell Materials written by Meysam Pazoki and published by Elsevier. This book was released on 2019-11-14 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: Characterization Techniques for Perovskite Solar Cell Materials: Characterization of Recently Emerged Perovskite Solar Cell Materials to Provide an Understanding of the Fundamental Physics on the Nano Scale and Optimize the Operation of the Device Towards Stable and Low-Cost Photovoltaic Technology explores the characterization of nanocrystals of the perovskite film, related interfaces, and the overall impacts of these properties on device efficiency. Included is a collection of both main and research techniques for perovskite solar cells. For the first time, readers will have a complete reference of different characterization techniques, all housed in a work written by highly experienced experts. - Explores various characterization techniques for perovskite solar cells and discusses both their strengths and weaknesses - Discusses material synthesis and device fabrication of perovskite solar cells - Includes a comparison throughout the work on how to distinguish one perovskite solar cell from another
Download or read book Optoelectronic Nanodevices written by Minas M. Stylianakis and published by MDPI. This book was released on 2020-04-15 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the last decade, novel graphene related materials (GRMs), perovskites, as well as metal oxides and other metal nanostructures have received the interest of the scientific community. Due to their extraordinary physical, optical, thermal, and electrical properties, which are correlated with their 2D ultrathin atomic layer structure, large interlayer distance, ease of functionalization, and bandgap tunability, these nanomaterials have been applied in the development or the improvement of innovative optoelectronic applications, as well as the expansion of theoretical studies and simulations in the fast-growing fields of energy (photovoltaics, energy storage, fuel cells, hydrogen storage, catalysis, etc.), electronics, photonics, spintronics, and sensing devices. The continuous nanostructure-based applications development has provided the ability to significantly improve existing products and to explore the design of materials and devices with novel functionalities. This book demonstrates some of the most recent trends and advances in the interdisciplinary field of optoelectronics. Most articles focus on light emitting diodes (LEDs) and solar cells (SCs), including organic, inorganic, and hybrid configurations, whereas the rest address photodetectors, transistors, and other well-known dynamic optoelectronic devices. In this context, this exceptional collection of articles is directed at a broad scientific audience of chemists, materials scientists, physicists, and engineers, with the goals of highlighting the potential of innovative optoelectronic applications incorporating nanostructures and inspiring their realization.
Download or read book Light Emitting Diodes And Photodetectors Based On Iii nitride And Colloidal Quantum Dot Materials written by Zhenyu Jiang and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work, we first proposed the tandem architecture for solution-processed near infrared PbSe colloidal quantum dot (CQD)-based photodetectors to address the high dark current issue. The tandem architecture not only absorbs the virtue of tandem solar cell by means of efficient photon-to-current conversion, but also functions as the effective barrier that can block the leakage current. More than three orders of magnitude reduction in dark current has been observed, along with an elevated photocurrent. The low temperature current-voltage characteristics revealed that the tandem architecture posed a high energy barrier which effectively blocks the dark current. Our results suggest that tandem architecture can be employed to developing high-performance solution-processed photodetector. The application of tandem photodetectors was further extended to sensors on flexible substrates where little study has been reported to date. Our results on flexible tandem photodetectors validate the high efficiency and detectivity of the tandem architecture. Two different bending states have been studied which revealed the small critical bend radii of ~8mm and ~3mm for tensile and compressive bending, respectively. The photodetector performance remains stable under mechanical stress which offers great potential of CQDs-based tandem photodetectors for flexible device applications. Furthermore, we have demonstrated the chip level integration of flip-chip light emitting diode (LED) with current rectifying GaN Schottky barrier diodes constituting the Wheatstone bridge circuitry for alternating current (AC) driving. The flip-chip LED scheme offers better p-contact, high light extraction efficiency and fast heat dissipation. The reflectance and turn-on voltage were investigated under various p-contact annealing conditions. The flip-chip alternating current LEDs (ACLEDs) demonstrated more than ~23% improvement in terms of energy conversion efficiency over top-emissive ACLEDs and offer the potential of using such device for high brightness, high power, high efficiency and high reliability solid state lighting applications. Finally, built on our studies of LEDs and photodetectors, and of chip level integration of LEDs and GaN Schottky barrier diodes. we, for the first time, proposed the integration of visible LEDs and UV GaN photodetectors for bi-directional optical wireless communication (OWC) applications. The LEDs function as transmitters to emit visible light signal whereas the photodetectors as receivers to collect UV signals. The crosstalk can be neglected due to the superior visible-blind property of GaN UV photodetector. The experimental results demonstrated that the LEDs and photodetectors can work together efficiently which opens up a new avenue for using such device for bi-directional OWC applications.
Download or read book Optical and Electrical Investigations of Light emitting Diodes Based on InGaP GaP Quantum Wells written by and published by . This book was released on 2007 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Luminescent Nanomaterials written by Odireleng Martin Ntwaeaborwa and published by CRC Press. This book was released on 2022-05-19 with total page 508 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent decades, luminescent nanomaterials have generated great interest in the scientific community due to their unique properties, which are different from those of their bulk counterparts, and their use in a wide variety of applications. Today, luminescent nanomaterials are used in a number of applications such as displays, solid-state lighting, solar cells, long afterglow, dosimetry, theft prevention, medical imaging, phototherapy, and quantum and gas sensing. This book presents cutting-edge research from experts in the field of synthesis and characterization of luminescent nanomaterials and their potential applications. It covers interesting topics in semiconductor physics, photochemistry, physical chemistry, materials science, and luminescence, and will be useful for beginners and advanced researchers interested in this field.
Download or read book Color Science and Photometry for Lighting with LEDs and Semiconductor Nanocrystals written by Talha Erdem and published by Springer. This book was released on 2019-01-18 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reviews the application of semiconductor nanocrystals also known as colloidal quantum dots (QDs) to LED lighting for indoors and outdoors as well as LED backlighting in displays, summarizing the color science of QDs for lighting and displays and presenting recent developments in QD-integrated LEDs and display research. By employing QDs in color-conversion LEDs, it is possible to simultaneously accomplish successful color rendition of the illuminated objects and a good spectral overlap between the emission spectrum of the light source and the sensitivity of the human eye at a warm white color temperature – something that is fundamentally challenging to achieve with conventional sources, such as incandescent and fluorescent lamps, and phosphor-based LEDs.
Download or read book Charge Carrier Balance in Lead Halide Perovskite Light Emitting Diodes written by Matthew R. Chua and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Charge balance in light emitting diodes (LEDs) is a critical determinant of their performance. Charge balance is directly related to the External Quantum Efficiency (EQE), and is thought to have additional effects on device endurance and stability. In this thesis I present a series of experiments and simulations to study the charge balance in Lead Halide Perovskite (LHP) emitter LEDs. These LHP LEDs, particularly Near-Infrared Emitters have demonstrated high EQE, and promising lifetime.However for many other emission wavelengths their performance and endurance is lacking. I first present a modified simultaneous Photoluminescence-Electroluminesence (PLEL) measurement, along with two methods of calibrating the absolute photon flux absorbed, namely Short-circuit current, and Absorption from reflection. This allows the determination of absolute PL efficiency in the device relative to EL efficiency, to obtain an absolute measure of charge balance. Our measurements suggest that in the prototypical high efficiency NIR ITO/ZnO/LHP/TFB/MoO3/Al planar structure, the charge efficiency or [eta]CB is 0.83-0.91 , consistent with the high observed EQE of 16-17%. Next a different hole transport layer poly-TPD is introduced and the device studied relative to the original TFB case. We find that although poly-TPD devices have charge balance approximately 1.3x worse relative to TFB devices, this is insufficient to account for the 3x difference in device EQE when considering the relative PL quantum yields (PLQY) of the emitter under partially-complete stack measurements. By performing PL quantum yield measurements in-situ on a device under hybrid electrical-optical excitation, it is found that the LHP in-device PLQY is increased significantly and transiently by electrical excitation, which allows us to resolve the contradictory charge balance and EQE results. These experiments are supported by transfer matrix based optical simulations that allow us to account for the possible optical effects encountered in the different PLQY measurement conditions. Optical simulations are also used to convert the observed external PLQY to Internal Quantum Efficiency, [eta]QY , for a standard comparison across all measurements. This thesis demonstrates the effectiveness of the quasi-DC PLEL measurement in determining absolute charge balance in a LHP device. This method can be further applied to a broader range of LHP devices to gain greater understanding of the effect charge transport layers and LHP emitters have on each other when used to create electrically pumped light emitting systems.
