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.
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.
Recently, lead halide perovskite quantum dots (QDs) have attracted much attention because of their excellent properties of high colour purity, tunable emission wavelength covering the whole visible region, and ultrahigh photoluminescence (PL) quantum yield. They are expected to be promising candidates for the next-generation cost-effective lighting and display sources. Here, we introduced the recent development in the direct solution-processed synthesis and ion exchange-based reactions, leading to organic/inorganic hybrid halide perovskites (CH3NH3PbX3; X = Cl, Br, I) and all-inorganic lead halide perovskites (CsPbX3; X = Cl, Br, I), and studied their optical properties related to exciton-related emission and quantum confinement effect. Finally, we reviewed the recent progresses on the perovskite light-emitting diodes (LEDs) based on CH3NH3PbX3 and CsPbX3 quantum dots and provided a critical outlook into the existing and future challenges.
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.
Perovskite Light Emitting Diodes An introduction to revolutionary display technology Perovskite Light Emitting Diodes, commonly referred to as Pe-LEDs, leverage a perovskite nanocrystal core to engender a luminous and efficient diode, holding the potential to bring about a paradigm shift in the realm of display technology. In recent times, Pe-LEDs have garnered substantial industrial interest due to their intrinsic capability to exhibit a diverse array of colors with exceptional fidelity, their operation at low voltage thresholds, and their straightforward structural composition. The prospective implications for enabling cost-effective, heightened-performance flat-panel displays as well as flexible display solutions remain notably profound. Perovskite Light Emitting Diodes: Materials and Devices presents a comprehensive and insightful overview of these diodes and their multifaceted applications. Commencing with an incisive exploration of the historical trajectory of this technology, alongside a delineation of its foundational materials and intricate device architectures, this compendium provides a gateway into both contemporaneous state-of-the-art deployments and the vanguard of ongoing research endeavors directed towards charting future advancements. Perovskite Light Emitting Diodes readers will also find: Stability analysis for different Pe-LED devices, a key aspect of creating physical displays Authorship by an established expert in organic electronics Detailed discussion of perovskite preparation methods including ultrasonic, solvent heat, thermal injection, and many more Perovskite Light Emitting Diodes is ideal for materials scientists, electrical engineers, solid state chemists, solid state physicists, inorganic chemists, and any researchers or engineers working with display technology.
Metal halide perovskites (MHPs) are recognized as promising semiconductor materials for a variety of optical and electrical device applications due to their cost-effective and outstanding optoelectronic properties. As one of the most significant applications, perovskite light-emitting diodes (PeLEDs) hold promise for future lighting and display technologies, attributed to their high photoluminescence quantum yield (PLQY), high color purity, and tunable emission color. The emission colors of PeLEDs can be tuned by mixing the halide anions, adjusting the size of perovskite nanocrystals, or changing the dimensionality of perovskites. However, in practice, all these different approaches have their own advantages and challenges. This thesis centres around the color tunability of perovskites, aiming to develop PeLEDs with different colors using different approaches. We first demonstrate red and near-infrared PeLEDs using a straightforward approach – in situ solution-processed perovskite quantum dots (PQDs). PQDs prepared from colloidal approaches are widely reported and used in LEDs. In contrast, PQDs prepared from the in situ approaches are hardly reported, although they have advantages for device applications. By employing aromatic ammonium iodide (1-naphthylmethyl ammonium iodide, NMAI) as an agent into perovskite precursor solutions, together with annealing temperature modulation, we obtain in situ grown PQDs delivering high external quantum efficiencies (EQEs) of up to 11.0% with tunable electroluminescence (EL) spectra (667 - 790 nm). Our in situ generated PQDs based on pure-halogen perovskites can be easily obtained through a simple deposition process and free of phase segregation, making them a more promising approach for tuning the emission colors of perovskite LEDs. We then move to blue PeLEDs using cesium-based mixed-Br/Cl perovskites. Although mixed halides are a straightforward strategy to tune the emission color, PeLEDs based on this approach suffer from poor color stability, which is attributed to surface defects at grain boundaries. Under the condition of optical excitations, light density over a certain value (a threshold), oxygen, and surface defects at perovskite grain boundaries are found to be key factors inducing photoluminescence (PL) spectral instability of CsPb(Br1?xClx)3 perovskites. Upon electrical bias, defects at grain boundaries provide undesirable halide migration channels, responsible for EL spectral instability issues. Through effective defect passivation, the PL spectral resistance to oxygen is enhanced; moreover, high-performance and color-stable blue PeLEDs are achieved, delivering a maximum luminance of 5351 cd m–2 and a peak EQE of 4.55% with a peak emission wavelength at 489 nm. These findings provide new insights into the color instability issue of mixed halide blue perovskites, against which we also demonstrate an effective strategy. We finally realize single-emissive-layer (EML) white PeLEDs by employing a mixed halide perovskite film as the EML. In spite of high-performance monochromatic blue, green, and red colors, the development of white PeLEDs, especially for single-EML ones, remains a very big challenge. By effective modulation of the halide salt precursors, we achieve single-EML white PeLEDs with Commission Internationale de L’Eclairage (CIE) coordinates of (0.33, 0.33), close to those (0.3128, 0.3290) of the CIE standard illuminant D65. This work not only provides a successful demonstration of a single-EML white PeLED, but also provides useful guidelines for the future development of highperformance single-EML white PeLEDs.
Perovskite Photovoltaics and Optoelectronics Discover a one-of-a-kind treatment of perovskite photovoltaics In less than a decade, the photovoltaics of organic-inorganic halide perovskite materials has surpassed the efficiency of semiconductor compounds like CdTe and CIGS in solar cells. In Perovskite Photovoltaics and Optoelectronics: From Fundamentals to Advanced Applications, distinguished engineer Dr. Tsutomu Miyasaka delivers a comprehensive exploration of foundational and advanced topics regarding halide perovskites. It summarizes the latest information and discussion in the field, from fundamental theory and materials to critical device applications. With contributions by top scientists working in the perovskite community, the accomplished editor has compiled a resource of central importance for researchers working on perovskite related materials and devices. This edited volume includes coverage of new materials and their commercial and market potential in areas like perovskite solar cells, perovskite light-emitting diodes (LEDs), and perovskite-based photodetectors. It also includes: A thorough introduction to halide perovskite materials, their synthesis, and dimension control Comprehensive explorations of the photovoltaics of halide perovskites and their historical background Practical discussions of solid-state photophysics and carrier transfer mechanisms in halide perovskite semiconductors In-depth examinations of multi-cation anion-based high efficiency perovskite solar cells Perfect for materials scientists, crystallization physicists, surface chemists, and solid-state physicists, Perovskite Photovoltaics and Optoelectronics: From Fundamentals to Advanced Applications is also an indispensable resource for solid state chemists and device/electronics engineers.
LEDs are in the midst of revolutionizing the lighting industry Up-to-date and comprehensive coverage of light-emitting materials and devices used in solid state lighting and displays Presents the fundamental principles underlying luminescence Includes inorganic and organic materials and devices LEDs offer high efficiency, long life and mercury free lighting solutions
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.
