Download or read book Defect and Grain Boundary Engineering for Enhanced Performances and Lifetimes of Hybrid Perovskite Solar Cells written by Nicholas Francis DeMarco and published by . This book was released on 2019 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: As the world energy consumption increases, the necessity for clean energy proves vital and urgent as catastrophic effects of global climate change are imminent. The sun delivers more energy to Earth in just over an hour than we have consumed over the course of last year, making solar technology a most promising candidate for a sustainable future. Currently, state-of-the-art silicon-based solar technologies dominate the market owed to their maturity in processing knowledge, performance reliability, and lifetime. Despite lower costs in recent years, the levelized cost of electricity of silicon-based solar PV technologies is still much greater than conventional fossil fuel sources, providing large incentive to find more cost-effective alternative solar PV technologies. Solution-processed solar technologies are appealing as a low-cost alternative, among which, hybrid perovskites have recently risen as a high performance solution-processed PV technology achieving laboratory scale efficiencies >23%, which are rapidly approaching those of conventional Si-based PV (~26%). However, owed to the solution-processed nature of perovskites, there are many associated defects and grain boundary regions that can adversely affect performances and lifetimes. In this dissertation, I will focus on addressing defect and grain boundary engineering, taking advantage of the wet chemical environment of perovskite thin film processing to manipulate crystallization dynamics and modulate defect and grain boundary properties. In Chapter 4, the guanidinium molecule was first discovered for use in hybrid perovskites. It was found that inclusion of guanidinium can provide extraordinary enhancements in photoluminescent properties of the thin film and enhanced open-circuit voltage of the devices. Based on further experimental analyses and results, we believe that the guanidinium ion serves to suppress formation of defects via lattice strain relaxation and also may serve as a passivant at grain boundaries, giving rise to these impressive improvements. This work opened the door to future works throughout my Ph.D. to control crystallization and defect properties. To further investigate the nature of controlling crystal growth and associated defect natures, a Lewis acid-base adduct approach was developed and is discussed in Chapter 5. The strength of interactios between the Lewis acid perovskite precursors and Lewis base additives were shown to greatly influence nucleation and growth dynamics. The Lewis base urea was found to provide great enhancement in crystal growth, producing larger sized grains and enhanced photoluminescent properties, alongside a greater performance and stability of the device. Lastly, in Chapter 6, the intrinsic stability of the perovskite thin film is addressed by utilizing the compositional and dimensional tenability of hybrid perovskite materials, utilizing a hybrid 3- and 2-dimensionality of the perovskite structure to lead to even further enhanced performances and long-term lifetimes. It was found that the 2-D perovskite forms around grains (at grain boundaries) to facilitate the production of high quality 3-D grains and serve as passivating layers to grain boundaries. These works provide important future directions for hybrid perovskite PV research to realize commercial technologies with competitive efficiencies, long lifetimes, and low costs. Conclusions and future outlooks of these works are discussed in Chapter 7.

Download or read book Hybrid Perovskite Solar Cells written by Hiroyuki Fujiwara and published by John Wiley & Sons. This book was released on 2022-01-10 with total page 612 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unparalleled coverage of the most vibrant research field in photovoltaics! Hybrid perovskites, revolutionary game-changing semiconductor materials, have every favorable optoelectronic characteristic necessary for realizing high efficiency solar cells. The remarkable features of hybrid perovskite photovoltaics, such as superior material properties, easy material fabrication by solution-based processing, large-area device fabrication by an inkjet technology, and simple solar cell structures, have brought enormous attentions, leading to a rapid development of the solar cell technology at a pace never before seen in solar cell history. Hybrid Perovskite Solar Cells: Characteristics and Operation covers extensive topics of hybrid perovskite solar cells, providing easy-to-read descriptions for the fundamental characteristics of unique hybrid perovskite materials (Part I) as well as the principles and applications of hybrid perovskite solar cells (Part II). Both basic and advanced concepts of hybrid perovskite devices are treated thoroughly in this book; in particular, explanatory descriptions for general physical and chemical aspects of hybrid perovskite photovoltaics are included to provide fundamental understanding. This comprehensive book is highly suitable for graduate school students and researchers who are not familiar with hybrid perovskite materials and devices, allowing the accumulation of the accurate knowledge from the basic to the advanced levels.

Download or read book Paradigms of Titanate Centered Energy Materials written by Sanjay J. Dhoble and published by CRC Press. This book was released on 2023-08-17 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: Titanate-centered perovskites are an important class of crystalline materials with outstanding structural and property tunability. Recently, titanate perovskites have been extensively investigated as new-generation materials for various energy-allied applications, together with photovoltaic cells, light emitting diodes, photo detectors and lasers, for their exceptional optical and electronic properties. With increasing attention on the development of nanotechnology and multidisciplinary research, scientists have been trying to downscale the titanate perovskite structures into the nanoregime, so as to further boost their performances and applications. Compared with bulk perovskite materials, perovskite nanomaterials exhibit a series of advantages, such as fabrication of thin films and flexible devices and PNMs display high process ability. Perovskite nanomaterials feature rich and controllable facets and active sites. Besides benefiting from the small-size effect and quantum effect, perovskite nanomaterials are endowed with outstanding photo-electromagnetic properties. Furthermore, the applications of titanate-centered perovskites in the fields of energy, environment, WLEDs, forensic science and piezoelectric devices will be reviewed. This book will also discuss the possible solutions to the problems in their application by optimizing their compositions, structures and preparation methods. This book will systematically summarize the key points in the design, synthesis, property improvements and application expansion of titanate-centered perovskites. The different perovskite structures and the rational design of functional materials will be discussed in detail. The advantages, disadvantages and experimental parameters of different synthesis methods for titanate-centered perovskites will be reviewed. This book will also summarize some practical experiences in selecting suitable elements and designing multifunctional materials according to the mechanisms and principles of elements promoting the properties of perovskites by covering almost last 20 years of literature. At the end of this book, we will provide an outlook on the opportunities and challenges in the view of development in titanate-centered perovskites The inclusive effectiveness and practicality of prospective titanate energy materials and systems are directly connected to many materials-related factors. This volume of book features totally seven sections that envelop a wide range of titanate energy materials. They cover the modern developments involving materials for alternative and renewable energy sources and systems, including energy storage and batteries, nanocomposites, hydrogen, solar, wind, geothermal, biomass and nuclear. The book is a significant orientation for students and researchers (from academics, but also industry) interested in understanding the properties of emerging titanate energy materials and challenges in the recent era.

Download or read book Hybrid Perovskite Solar Cells written by Hiroyuki Fujiwara and published by John Wiley & Sons. This book was released on 2021-10-07 with total page 612 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unparalleled coverage of the most vibrant research field in photovoltaics! Hybrid perovskites, revolutionary game-changing semiconductor materials, have every favorable optoelectronic characteristic necessary for realizing high efficiency solar cells. The remarkable features of hybrid perovskite photovoltaics, such as superior material properties, easy material fabrication by solution-based processing, large-area device fabrication by an inkjet technology, and simple solar cell structures, have brought enormous attentions, leading to a rapid development of the solar cell technology at a pace never before seen in solar cell history. Hybrid Perovskite Solar Cells: Characteristics and Operation covers extensive topics of hybrid perovskite solar cells, providing easy-to-read descriptions for the fundamental characteristics of unique hybrid perovskite materials (Part I) as well as the principles and applications of hybrid perovskite solar cells (Part II). Both basic and advanced concepts of hybrid perovskite devices are treated thoroughly in this book; in particular, explanatory descriptions for general physical and chemical aspects of hybrid perovskite photovoltaics are included to provide fundamental understanding. This comprehensive book is highly suitable for graduate school students and researchers who are not familiar with hybrid perovskite materials and devices, allowing the accumulation of the accurate knowledge from the basic to the advanced levels.

Download or read book Grain Boundary Defect Passivation of Mixed Cation Perovskite Solar Cell to Improve Device Performance written by Sheikh Ifatur Rahman and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Defect Passivation in Hybrid Perovskite Solar Cells by Zwitterions written by Xiaopeng Zheng and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The ionic defects on the surfaces and at the grain boundaries of organic-inorganic halide perovskite films are detrimental to the efficiency and stability of perovskite solar cells. In chapter 3, we showed that the zwitterions can effectively passivate ionic defects in several different types of hybrid perovskites with negatively and positively charged components. The efficient defect passivation reduces the charge-trap density and extends the carrier recombination lifetime- supported by calculating the density function. The defect passivation reduces the open-circuit-voltage deficit of the p-i-n structured device to 0.39 V and boosts the efficiency to a certified value of 20.59±0.45%. Moreover, the defect healing also significantly enhances the stability of films in ambient conditions. Our findings provide an avenue for defect passivation to further improve the efficiency and stability of solar cells. The uniform and high-electronic-quality of perovskite thin films are essential for high-performance perovskite devices. Here, it was shown that the 3-[Dodecyl(dimethyl)ammonio]-1-propanesulfonate inner salt (DPSI), which is a zwitterionic lead (II)-coordination long chain molecule, plays dual roles in tuning the crystallization behavior and passivating defects of perovskites. The synergistic effect of crystallization control and defect passivation remarkably suppresses the pin-hole formation, reduces the charge trap density, and elongates the carrier recombination lifetime, boosting the planar perovskite device efficiency to 21.1%. Our findings provide an avenue for simultaneous crystallization control and defect passivation to further improve the performance of perovskite devices.

Download or read book Handbook of Perovskite Solar Cells Volume 2 written by Jiangzhao Chen and published by CRC Press. This book was released on 2024-09-27 with total page 465 pages. Available in PDF, EPUB and Kindle. Book excerpt: Perovskite solar cells (PSCs) have received significant attention in academia and industry due to their low cost and high-power conversion efficiency (PCE). Single- and multijunction PSCs have obtained promising certified PCEs, which suggests that PSCs are a very promising next-generation photovoltaic technology. In addition to the perovskite absorber layer, other functional layers, including electron transport layer (ETL), hole transport layer (HTL), and electrode layer (EL), have also made huge contributions to enhancing device performance. This book focuses on the development, advancement, and application of these functional layers in various PSCs. This volume: Introduces ETL, HTL, and EL in efficient and stable PSCs. Covers material properties. Discusses a wide variety of PSCs including single-crystal PSCs, flexible PSCs, perovskite tandem solar cells, lead-free PSCs, inorganic PSCs, fully printable mesoscopic PSCs, electron/hole-transport-layer-free PSCs, semitransparent PSCs for building-integrated photovoltaics (BIPV), tandem solar cells, perovskite indoor photovoltaics, and inverted PSCs. Details potential for commercial application. This book is aimed at researchers, advanced students, and industry professionals in materials, energy, and related areas of engineering who are interested in development and commercialization of photovoltaic technologies.

Download or read book Halide Perovskites written by Tze-Chien Sum and published by John Wiley & Sons. This book was released on 2019-03-25 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Towards High Efficiency and Stable Metal Halide Perovskite Solar Cells written by Yepin Zhao and published by . This book was released on 2021 with total page 169 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metal halide perovskite solar cells have proven themselves as one of the most promising candidates to replace the currently well-commercialized silicon-based solar cells. Because of its unique energy band structure, it has merits such as high defect tolerance, favorable charge carrier mobility, and high absorption coefficient. However, the major issue that hinders the successful real-life application of the metal halide perovskite solar cell is its unsatisfactory stability. In Chapter One, I introduce the four basic elements that cause the instability of perovskite solar cells: light, heat, bias, and moisture. The perovskite material degradation mechanism behind each environment will be detailly illustrated. Ion migration suppression and device encapsulation can be regarded as the main solutions to enhance the operational lifetime of the perovskite solar cells. From interior to exterior, in the following chapters, I introduce the strategies we developed that are proven to be powerful to improve the stability of the metal halide perovskite solar cells.In Chapter Two, I introduce the first strategy of interior multivalent interstitial doping. It is a strategy originated inside the perovskite lattice. Cations with suitable sizes to occupy an interstitial site of perovskite crystals have been widely used to inhibit ion migration and promote the performance and stability of perovskite optoelectronics. However, the interstitial doping accompanies inevitable lattice strain to impair the long-range ordering and stability of the crystals to cause a sacrificial trade-off. In this chapter, I unravel the evident influence of the valence states of the interstitial cations on their efficacy to suppress the ion migration. Incorporation of a trivalent neodymium cation (Nd3+) effectively mitigates the ion migration in the perovskite lattice with a significantly reduced dosage (0.08%) compared to a widely used monovalent cation dopant (Na+, 0.45%). Less but better, the prototypical perovskite solar cells incorporated with Nd3+ exhibits significantly enhanced photovoltaic performance and operational stability. In Chapter Three, I discuss the defect passivation of the perovskite crystal, which constitutes one of the most commonly used strategies to fabricate highly efficient perovskite solar cells (PSCs). The durability of the passivation effects under harsh operational conditions has not been extensively studied regardless of the weak and vulnerable secondary bonding between the molecular passivation agents and perovskite crystals. Here, we incorporated strategically designed passivating agents to investigate the effect of their interaction energies with the perovskite crystals and correlated these with the performance and longevity of the passivation effects. We unraveled that the passivation agents with a stronger interaction energy are advantageous not only for effective defect passivation, but also to suppress defect migration. The prototypical PSCs treated with the optimal passivation agent exhibited superior performance and operational stability, retaining 81.9% and 85.3% of their initial performance under continuous illumination or nitrogen at 85 °C after 1008 hours, respectively while the reference device completely degraded during the time. This work provides important insights into designing operationally durable defect passivation agents for perovskite optoelectronic devices. In Chapter Four, we focus on the perovskite grain and the grain boundary density. Intrinsically, detrimental defects accumulating at the surface and grain boundaries limit both the performance and stability of perovskite solar cells. Small molecules and bulkier polymers with functional groups are utilized to passivate these ionic defects but usually suffer from volatility and precipitation issues, respectively. Starting from the addition of small monomers in PbI2 precursor, in this chapter, I introduce a polymerization-assisted grain growth (PAGG) strategy in the sequentially deposited method. With a polymerization process triggered during the PbI2 film annealing, the bulkier polymers formed will be adhered to the grain boundaries, remaining the previously established interactions with PbI2. After perovskite formation, the polymers anchored on the boundaries can effectively passivate under-coordinated lead ions and reduce defect density. As a result, we obtain a champion power conversion efficiency (PCE) of 23.0%, together with a prolonged lifetime where 85.7% and 91.8% of the initial PCE remains after 504-hour continuous illumination and 2208-hour shelf storage, respectively. In Chapter Five, I will go to the exterior of the perovskite solar cell and introduce a novel strategy of device encapsulation. Unstable nature against moisture is one of the major issues of metallic halide perovskite solar cell application. Thin-film encapsulation is known as a powerful approach to notably enhance the operational stability of perovskite solar cells in a humid environment. However, encapsulation layers with ideal gas barrier performance always require harsh fabrication conditions with high temperature and harmful precursors. For this reason, here we provide a mild encapsulation strategy to maintain the original performance of solar cell devices by utilization of ethylene glycol-induced immediate layer to minimize the damage of plasma-enhanced atomic layer deposition to perovskite solar cells. The organic-inorganic alternating encapsulation structure has exhibited a water vapor transmittance rate of 1.3 10-5 g m-2 day-1, which is the lowest value among the reported thin-film encapsulation layers of perovskite solar cells. Our perovskite solar cells have survived at 80% relative humidity and 30 C for over 2000 hours while preserving 96% of their initial performance.

Download or read book Perovskite Solar Cells written by Shahzada Ahmad and published by John Wiley & Sons. This book was released on 2022-03-14 with total page 580 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presents a thorough overview of perovskite research, written by leaders in the field of photovoltaics The use of perovskite-structured materials to produce high-efficiency solar cells is a subject of growing interest for academic researchers and industry professionals alike. Due to their excellent light absorption, longevity, and charge-carrier properties, perovskite solar cells show great promise as a low-cost, industry-scalable alternative to conventional photovoltaic cells. Perovskite Solar Cells: Materials, Processes, and Devices provides an up-to-date overview of the current state of perovskite solar cell research. Addressing the key areas in the rapidly growing field, this comprehensive volume covers novel materials, advanced theory, modelling and simulation, device physics, new processes, and the critical issue of solar cell stability. Contributions by an international panel of researchers highlight both the opportunities and challenges related to perovskite solar cells while offering detailed insights on topics such as the photon recycling processes, interfacial properties, and charge transfer principles of perovskite-based devices. Examines new compositions, hole and electron transport materials, lead-free materials, and 2D and 3D materials Covers interface modelling techniques, methods for modelling in two and three dimensions, and developments beyond Shockley-Queisser Theory Discusses new fabrication processes such as slot-die coating, roll processing, and vacuum sublimation Describes the device physics of perovskite solar cells, including recombination kinetics and optical absorption Explores innovative approaches to increase the light conversion efficiency of photovoltaic cells Perovskite Solar Cells: Materials, Processes, and Devices is essential reading for all those in the photovoltaic community, including materials scientists, surface physicists, surface chemists, solid state physicists, solid state chemists, and electrical engineers.

Download or read book Handbook of Perovskite Solar Cells Volume 1 written by Jiangzhao Chen and published by CRC Press. This book was released on 2024-10-29 with total page 453 pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic–inorganic hybrid metal halide perovskite materials have attracted significant attention due to their advantages of low cost, tunable band gap, solution processing, high molar extinction coefficient, low exciton binding energy, and high carrier mobility. Perovskite absorber layers play a decisive role in the realization of high-power conversion efficiency in perovskite solar cells (PSCs). This book systematically and comprehensively discusses device structures, working principles, and optimization strategies of perovskite absorber layers for PSCs to help foster commercialization of these environmentally friendly power sources. It describes strategies to optimize the quality of perovskite films, including composition engineering, dimensional engineering, solvent engineering, strain engineering, additive engineering, and interface engineering. This volume: Introduces crystal structures of perovskites, configurations of PSCs, and their working principles Discusses the modulation of perovskite compositions and dimensionality towards highly stable and efficient perovskite photovoltaics Details the advancements of low-dimensional PSCs including phase stability of perovskite films and strategies for modulating phases Summarizes progress in solvent engineering, additive engineering, and strain engineering in efficient and scalable perovskite photovoltaics Describes the complex crystallization dynamics of perovskites, interface engineering, and synergistic modulation of grain boundaries and interfaces in PSCs Highlights advances in ion migration and mitigation in halide perovskite solar cells and origins and elimination of hysteresis This book is aimed at researchers, advanced students, and industry professionals in materials, energy, and related areas of engineering who are interested in development and commercialization of photovoltaic technologies.

Download or read book Grain Boundaries written by Louisette Priester and published by Springer. This book was released on 2014-12-14 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Grain boundaries are a main feature of crystalline materials. They play a key role in determining the properties of materials, especially when grain size decreases and even more so with the current improvements of processing tools and methods that allow us to control various elements in a polycrystal. This book presents the theoretical basis of the study of grain boundaries and aims to open up new lines of research in this area. The treatment is light on mathematical approaches while emphasizing practical examples; the issues they raise are discussed with reference to theories. The general approach of the book has two main goals: to lead the reader from the concept of ‘ideal’ to ‘real’ grain boundaries; to depart from established knowledge and address the opportunities emerging through "grain boundary engineering", the control of morphological and crystallographic features that affect material properties. The book is divided in three parts: I ‘From interganular order to disorder’ deals with the concept of the perfect grain boundary, at equilibrium, and questions the maintenance of its crystalline state. II ‘From the ideal to the real grain boundary’ deals with the concept of the faulted grain boundary. It attempts to reveal the influence of the grain boundary structure on its defects, their formation and their accommodation. III ‘From free to constrained grain boundaries’ is devoted to grain boundary ensembles starting from the triple junction (the elemental configuration) to real grain boundary networks in polycrystals This part covers a new and topical development in the field. It presents for the first time an avenue for researchers working on macroscopic aspects, to approach the scale of description of grain boundaries. Audience: graduate students, researchers and engineers in Materials Science and all those scientists pursuing grain boundary engineering in order to improve materials performance.

Download or read book Perovskite Photovoltaics and Optoelectronics written by Tsutomu Miyasaka and published by John Wiley & Sons. This book was released on 2022-03-21 with total page 484 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Perovskite Photovoltaics written by Aparna Thankappan and published by Academic Press. This book was released on 2018-06-29 with total page 521 pages. Available in PDF, EPUB and Kindle. Book excerpt: Perovskite Photovoltaics: Basic to Advanced Concepts and Implementation examines the emergence of perovskite photovoltaics, associated challenges and opportunities, and how to achieve broader development. Consolidating developments in perovskite photovoltaics, including recent progress solar cells, this text also highlights advances and the research necessary for sustaining energy. Addressing different photovoltaics fields with tailored content for what makes perovskite solar cells suitable, and including commercialization examples of large-scale perovskite solar technology. The book also contains a detailed analysis of the implementation and economic viability of perovskite solar cells, highlighting what photovoltaic devices need to be generated by low cost, non-toxic, earth abundant materials using environmentally scalable processes. This book is a valuable resource engineers, scientists and researchers, and all those who wish to broaden their knowledge on flexible perovskite solar cells. Includes contributions by leading solar cell academics, industrialists, researchers and institutions across the globe Addresses different photovoltaics fields with tailored content for what makes perovskite solar cells different Provides commercialization examples of large-scale perovskite solar technology, giving users detailed analysis on the implementation, technical challenges and economic viability of perovskite solar cells

Download or read book Non wetting Surface driven High aspect ratio Crystalline Grain Growth for Efficient Hybrid Perovskite Solar Cells written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Large-aspect-ratio grains are needed in polycrystalline thin-film solar cells for reduced charge recombination at grain boundaries; however, the grain size in organolead trihalide perovskite (OTP) films is generally limited by the film thickness. Here we report the growth of OTP grains with high average aspect ratio of 2.3-7.9 on a wide range of non-wetting hole transport layers (HTLs), which increase nucleus spacing by suppressing heterogeneous nucleation and facilitate grain boundary migration in grain growth by imposing less drag force. The reduced grain boundary area and improved crystallinity dramatically reduce the charge recombination in OTP thin films to the level in OTP single crystals. Combining the high work function of several HTLs, a high stabilized device efficiency of 18.3% in low-temperature-processed planar-heterojunction OTP devices under 1 sun illumination is achieved. As a result, this simple method in enhancing OTP morphology paves the way for its application in other optoelectronic devices for enhanced performance.

Download or read book Defect Passivation Towards Highly Efficient and Stable Metal Halide Perovskite Solar Cells written by Rui Wang and published by . This book was released on 2020 with total page 269 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metal halide perovskite material had emerged as a rising star in the photovoltaic application due to its excellent optoelectronic properties. Perovskite solar cells with a power conversion efficiency of over 25% have been demonstrated within a few years. However, the stability issues of this material still prohibit the commercialization of perovskite solar cells because of the low ion-migration activation energy, phase instability at room temperature, and sensitivity to the external environments. Attacked by the external environments through the defects in the perovskite has been considered one of the most critical issues of the instability of perovskite solar cells. Since the defects are preferred formed at the surface and grain boundaries of the perovskite, developing facile and effective strategies to passivate the defects at surface and grain boundaries is essential to enhance the stability and efficiency of perovskite solar cells. In Chapter two, 1,3,7-Trimethylxanthine, a commodity chemical with two conjugated carboxyl groups better known by its common name caffeine, improves the performance and thermal stability of perovskite solar cells based on both MAPbI3 and CsFAMAPbI3 active layers. The strong interaction between caffeine and Pb2+ ions serves as a "molecular lock" that increases the activation energy during film crystallization, delivering a perovskite film with a preferred orientation, improved electronic properties, reduced ion migration, and greatly enhanced thermal stability. A champion stabilized efficiency of 19.8% and retain over 85% of their efficiency under continuous annealing at 85 C in nitrogen. Later on, in Chapter three, CuBr2 was introduced into the all-inorganic perovskites to control the crystallization and passivate the grain boundary defects, therefore a power conversion efficiency of over 16% was realized. Apart from grain passivation by modulating the crystallization process of perovskites, a facile surface-induced secondary grain growth by utilizing the surface anisotropic was developed to enlarge the grain size to reduce the grain boundaries. As a result, grain size as large as 4 microns was realized through the oleylammonium treatment, the power conversion efficiency of 16.58% was achieved with 4,000-hour shelf stability. In Chapter 5, the chemical environment of a functional group that is activated for defect passivation was systematically investigated with theophylline, caffeine and theobromine. When N-H and C=O were in an optimal configuration within the molecule, hydrogen-bond formation between N-H and I assisted the primary C=O binding with the antisite Pb defect to maximize surface-defect binding. A stabilized power conversion efficiency of 22.6% of photovoltaic device was demonstrated with theophylline treatment.

Download or read book Organic Inorganic Halide Perovskite Photovoltaics written by Nam-Gyu Park and published by Springer. This book was released on 2016-07-25 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers fundamentals of organometal perovskite materials and their photovoltaics, including materials preparation and device fabrications. Special emphasis is given to halide perovskites. The opto-electronic properties of perovskite materials and recent progress in perovskite solar cells are described. In addition, comments on the issues to current and future challenges are mentioned.