Download or read book Charge Transport and Recombination in Hybrid Organic inorganic Solar Cells written by Alexander Robert Pascoe and published by . This book was released on 2015 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hybrid organic-inorganic solar cells have been cited as a promising alternative to presently commercialised photovoltaic technologies. However, despite over 20 years of research into hybrid organic-inorganic solar technologies, there are still many unknowns concerning the physical operation of these devices. The two most successful technologies comprising the discipline of hybrid organic-inorganic solar cells are the dye-sensitised solar cell (DSSC) and the perovskite-based solar cell (PSC). This thesis reports on charge transport and recombination mechanisms occurring within DSSC and PSC devices.The first phase of this work examined the role of electron traps on charge recombination in DSSCs, and whether reports of trap state passivation were justified. Electrochemical impedance spectroscopy (EIS) and intensity-modulated photovoltage spectroscopy (IMVS) were used to characterise nanoparticle TiO2 films treated with an atomic layer deposited (ALD) coating. The application of a theoretical model to the experimental data was used to characterise the relative contributions of conductive states and trap states to the total recombination rate. The interpretation of these results indicated that the ALD surface treatment reduced recombination from conductive and trap states evenly, and did not selectively passivate surface traps.The second phase of this thesis explored the physical characteristics of DSSCs formed on flexible plastic substrates, as well as electron transport rates within nanostructured TiO2 beads. EIS, IMVS, intensity-modulated photocurrent spectroscopy (IMPS) and transient measurements revealed that the benchmark fabrication techniques of cold isostatic pressing (CIP) and nanoglue treatments resulted in electron diffusion lengths 3 - 4 times shorter than those produced via a high-temperature sintering step. Characterisation of charge transport kinetics within mesoporous TiO2 beads identified two effective diffusion rates: one pertaining to intra-bead diffusion, and the other to inter-bead connections.The third phase of this work entailed the characterisation of planar PSCs primarily through EIS. Impedance spectroscopy measurements of planar PSC devices revealed high-frequency and low-frequency features that exhibited different dependencies on the charge carrier concentration. Based on additional photoluminescence (PL) and transient measurements, as well as the formative work of previous studies, an equivalent circuit model was proposed to describe the impedance spectroscopic response of planar PSC devices.The final phase of this thesis aimed to characterise the differences in transport and recombination dynamics between planar and mesoscopic architectures. Time-resolved microwave conductivity (TRMC) and time-resolved PL measurements revealed higher charge mobilities and lower trap-mediated recombination dynamics in planar perovskite films compared to mesoscopic perovskite films. The consolidation of the best aspects of each architecture into a new PSC assembly was found to increase the overall power conversion efficiency. In an extension of this work, a different perovskite precursor solution was used to produce a textured, mesoscopic perovskite layer without the use of a thick nanoparticle scaffold. This textured morphology was capable of enhancing further the optical and charge separation properties of the device, resulting in a maximum power conversion efficiency of 16.3 %. The work undertaken in the aforementioned studies highlights how a deeper understanding of hybrid organic-inorganic solar cell physics can be used to further optimise the solar cell performance.
Download or read book Charge Generation and Recombination in Hybrid Organic Inorganic Solar Cells written by Michael Meister and published by . This book was released on 2013 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Organic and Hybrid Solar Cells written by Lukas Schmidt-Mende and published by Walter de Gruyter GmbH & Co KG. This book was released on 2022-08-01 with total page 494 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the increasing world-energy demand there is a growing necessity for clean and renewable energy. This book offers an introduction to novel types of solar cells, which are processed from solution. We discuss fabrication, different architectures and their device physics of these solar cells on the bases of the author‘s teaching course on a master degree level. A comparison with conventional solar cells is given and the specialties of organic, hybrid and perovskite solar cells are emphasized.
Download or read book Non Equilibrium Charge Motion in Organic Solar Cells written by Armantas Melianas and published by Linköping University Electronic Press. This book was released on 2017-04-18 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic photovoltaic (OPV) devices based on semiconducting polymers and small molecules allow for a low cost alternative to inorganic solar cells. Recent developments show power conversion efficiencies as high as 10-12%, highlighting the potential of this technology. Nevertheless, further improvements are necessary to achieve commercialization. To a large extent the performance of these devices is dictated by their ability to extract the photo-generated charge, which is related to the charge carrier mobility. Various time-resolved and steady-state techniques are available to probe the charge carrier mobility in OPVs but often lead to different mobility values for one and the same system. Despite such conflicting observations it is generally assumed that charge transport in OPV devices can be described by well-defined charge carrier mobilities, typically obtained using a single steady-state technique. This thesis shows that the relevance of such well-defined mobilities for the charge separation and extraction processes is very limited. Although different transient techniques probe different time scales after photogeneration, they are mutually consistent as they probe the same physical mechanism governing charge motion – gradual thermalization of the photo-generated carriers in the disorder broadened density of states (DOS). The photo-generated carriers gradually lose their excess energy during transport to the extracting electrodes, but not immediately. Typically not all excess energy is dissipated as the photo-generated carriers tend to be extracted from the OPV device before reaching quasi-equilibrium. Carrier motion is governed by thermalization, leading to a time-dependent carrier mobility that is significantly higher than the steady-state mobility. This picture is confirmed by several transient techniques: Time-resolved Terahertz Spectroscopy (TRTS), Time-resolved Microwave Conductance (TRMC) combined with Transient Absorption (TA), electrical extraction of photo-induced charges (photo-CELIV). The connection between transient and steady-state mobility measurements (space-charge limited conductivity, SCLC) is described. Unification of transient opto-electric techniques to probe charge motion in OPVs is presented. Using transient experiments the distribution of extraction times of photo-generated charges in an operating OPV device has been determined and found to be strongly dispersive, spanning several decades in time. In view of the strong dispersion in extraction times the relevance of even a well-defined time-dependent mean mobility is limited. In OPVs a continuous ‘percolating’ donor network is often considered necessary for efficient hole extraction, whereas if the network is discontinuous, hole transport is thought to deteriorate significantly, limiting device performance. Here, it is shown that even highly diluted donor sites (5.7-10 %) in a buckminsterfullerene (C60) matrix enable reasonably efficient hole transport. Using transient measurements it is demonstrated that hole transport between isolated donor sites can occur by long-range hole tunneling (over distances of ~4 nm) through several C60 molecules – even a discontinuous donor network enables hole transport
Download or read book Organic and Hybrid Solar Cells written by Lukas Schmidt-Mende and published by Walter de Gruyter GmbH & Co KG. This book was released on 2016-05-24 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the increasing world-energy demand there is a growing necessity for clean and renewable energy. The sun being one of the most abundant potential sources accounts for less than 1% of the global energy supply. The market for solar cells is one of the most strongly increasing markets, even though the prize of conventional solar cells is still quite high. New emerging technologies, such as organic and hybrid solar cells have the potential to decrease the price of solar energy drastically. This book offers an introduction to these new types of solar cells and discusses fabrication, different architectures and their device physics on the bases of the author's teaching course on a master degree level. A comparison with conventional solar cells will be given and the specialties of organic solar cells emphasized.
Download or read book Organic Inorganic and Hybrid Solar Cells written by Ching-Fuh Lin and published by John Wiley & Sons. This book was released on 2012-09-04 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides detailed descriptions of organic, inorganic, and hybrid solar cells and the latest developments in the quest to produce low-cost, long-lasting solar cells What will it take to transform solar energy from an important alternative source to a truly competitive and, perhaps, dominant one? Lower cost and longer life. Organic, Inorganic, and Hybrid Solar Cells: Principles and Practice provides in-depth information on the three types of existing solar cells, giving readers a good foundation for evaluating the technologies with the most potential for competing with energy from fossil fuels. Featuring a Foreword written by Nobel Peace Prize co-winner Dr. Woodrow W. Clark, this timely and comprehensive guide: Focuses on the realization of low-cost and long-life solar cells study and applications Reviews the properties of inorganic materials, primarily semiconductors Explores the electrical and optical properties of organic materials Discusses the interfacing of organic and inorganic materials: compatibility of deposition, the adhesion problem, formation of surface states, and band-level realignment Provides a detailed description of organic-inorganic hybrid solar cells, from the basic principles to practical devices Introduces a sandwiched structure for hybrid solar cells, which combines a far lower production cost than inorganic solar cells while stabilizing and extending the life of organic material far beyond that of organic solar cells Organic, Inorganic, and Hybrid Solar Cells: Principles and Practice is a first-rate professional reference for electrical engineers and important supplemental reading for graduate students in related areas of study.
Download or read book Comprehensive Guide on Organic and Inorganic Solar Cells written by Md. Akhtaruzzaman and published by Academic Press. This book was released on 2021-11-18 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comprehensive Guide on Organic and Inorganic Solar Cells: Fundamental Concepts to Fabrication Methods is a one-stop, authoritative resource on all types of inorganic, organic and hybrid solar cells, including their theoretical background and the practical knowledge required for fabrication. With chapters rigorously dedicated to a particular type of solar cell, each subchapter takes a detailed look at synthesis recipes, deposition techniques, materials properties and their influence on solar cell performance, including advanced characterization methods with materials selection and experimental techniques. By addressing the evolution of solar cell technologies, second generation thin-film photovoltaics, organic solar cells, and finally, the latest hybrid organic-inorganic approaches, this book benefits students and researchers in solar cell technology to understand the similarities, differences, benefits and challenges of each device. Introduces the basic concepts of different photovoltaic cells to audiences from a wide variety of academic backgrounds Consists of working principles of a particular category of solar technology followed by dissection of every component within the architecture Crucial experimental procedures for the fabrication of solar cell devices are introduced, aiding picture practical application of the technology
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 Organic Solar Cells written by Wolfgang Tress and published by Springer. This book was released on 2014-11-22 with total page 474 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers in a textbook-like fashion the basics or organic solar cells, addressing the limits of photovoltaic energy conversion and giving a well-illustrated introduction to molecular electronics with focus on the working principle and characterization of organic solar cells. Further chapters based on the author’s dissertation focus on the electrical processes in organic solar cells by presenting a detailed drift-diffusion approach to describe exciton separation and charge-carrier transport and extraction. The results, although elaborated on small-molecule solar cells and with focus on the zinc phthalocyanine: C60 material system, are of general nature. They propose and demonstrate experimental approaches for getting a deeper understanding of the dominating processes in amorphous thin-film based solar cells in general. The main focus is on the interpretation of the current-voltage characteristics (J-V curve). This very standard measurement technique for a solar cell reflects the electrical processes in the device. Comparing experimental to simulation data, the author discusses the reasons for S-Shaped J-V curves, the role of charge carrier mobilities and energy barriers at interfaces, the dominating recombination mechanisms, the charge carrier generation profile, and other efficiency-limiting processes in organic solar cells. The book concludes with an illustrative guideline on how to identify reasons for changes in the J-V curve. This book is a suitable introduction for students in engineering, physics, material science, and chemistry starting in the field of organic or hybrid thin-film photovoltaics. It is just as valuable for professionals and experimentalists who analyze solar cell devices.
Download or read book Organic and Hybrid Solar Cells written by Hui Huang and published by Springer. This book was released on 2014-11-25 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book delivers a comprehensive evaluation of organic and hybrid solar cells and identifies their fundamental principles and numerous applications. Great attention is given to the charge transport mechanism, donor and acceptor materials, interfacial materials, alternative electrodes, device engineering and physics, and device stability. The authors provide an industrial perspective on the future of photovoltaic technologies.
Download or read book Organic Solar Cells written by Qiquan Qiao and published by CRC Press. This book was released on 2017-12-19 with total page 510 pages. Available in PDF, EPUB and Kindle. Book excerpt: Current energy consumption mainly depends on fossil fuels that are limited and can cause environmental issues such as greenhouse gas emissions and global warming. These factors have stimulated the search for alternate, clean, and renewable energy sources. Solar cells are some of the most promising clean and readily available energy sources. Plus, the successful utilization of solar energy can help reduce the dependence on fossil fuels. Recently, organic solar cells have gained extensive attention as a next-generation photovoltaic technology due to their light weight, mechanical flexibility, and solution-based cost-effective processing. Organic Solar Cells: Materials, Devices, Interfaces, and Modeling provides an in-depth understanding of the current state of the art of organic solar cell technology. Encompassing the full spectrum of organic solar cell materials, modeling and simulation, and device physics and engineering, this comprehensive text: Discusses active layer, interfacial, and transparent electrode materials Explains how to relate synthesis parameters to morphology of the photoactive layer using molecular dynamics simulations Offers insight into coupling morphology and interfaces with charge transport in organic solar cells Explores photoexcited carrier dynamics, defect states, interface engineering, and nanophase separation Covers inorganic–organic hybrids, tandem structure, and graphene-based polymer solar cells Organic Solar Cells: Materials, Devices, Interfaces, and Modeling makes an ideal reference for scientists and engineers as well as researchers and students entering the field from broad disciplines including chemistry, material science and engineering, physics, nanotechnology, nanoscience, and electrical engineering.
Download or read book Aspects of Charge Recombination and Charge Transport in Organic Solar Cells and Light emitting Devices written by Seth Difley and published by . This book was released on 2010 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, aspects of charge reconbination and charge transport in organic solar cells and light-emitting devices are presented. These devices show promise relative to traditional inorganic semiconductors. We show that the energy splitting between singlet and triplet CT states in organic materials is appreciable and is material and geometry dependent. This prediction is used to guide the development of an OLED with enhanced fluorescence. The effects of nuclear disorder on optical and transport properties in organic semiconductors are examined and a general computational method for carrying out this analysis is described. The function of organic semiconductors is characterized by the interplay between localized and delocalized excited states. We present an ab initio method for obtaining the electronic coupling between CT states and excitons and (discuss the nonadiabatic transitions between these states.
Download or read book Organic Solar Cells written by Wallace C.H. Choy and published by Springer Science & Business Media. This book was released on 2012-11-19 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic solar cells have emerged as new promising photovoltaic devices due to their potential applications in large area, printable and flexible solar panels. Organic Solar Cells: Materials and Device Physics offers an updated review on the topics covering the synthesis, properties and applications of new materials for various critical roles in devices from electrodes, interface and carrier transport materials, to the active layer composed of donors and acceptors. Addressing the important device physics issues of carrier and exciton dynamics and interface stability and novel light trapping structures, the potential for hybrid organic solar cells to provide high efficiency solar cells is examined and discussed in detail. Specific chapters covers key areas including: Latest research and designs for highly effective polymer donors/acceptors and interface materials Synthesis and application of highly transparent and conductive graphene Exciton and charge dynamics for in-depth understanding of the mechanism underlying organic solar cells. New potentials and emerging functionalities of plasmonic effects in OSCs Interface Degradation Mechanisms in organic photovoltaics improving the entire device lifetime Device architecture and operation mechanism of organic/ inorganic hybrid solar cells for next generation of high performance photovoltaics This reference can be practically and theoretically applied by senior undergraduates, postgraduates, engineers, scientists, researchers, and project managers with some fundamental knowledge in organic and inorganic semiconductor materials or devices.
Download or read book Hybrid Organic Inorganic Perovskites written by Li Wei and published by John Wiley & Sons. This book was released on 2020-10-19 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hybrid organic-inorganic perovskites (HOIPs) have attracted substantial interest due to their chemical variability, structural diversity and favorable physical properties the past decade. This materials class encompasses other important families such as formates, azides, dicyanamides, cyanides and dicyanometallates. The book summarizes the chemical variability and structural diversity of all known hybrid organic-inorganic perovskites subclasses including halides, azides, formates, dicyanamides, cyanides and dicyanometallates. It also presents a comprehensive account of their intriguing physical properties, including photovoltaic, optoelectronic, dielectric, magnetic, ferroelectric, ferroelastic and multiferroic properties. Moreover, the current challenges and future opportunities in this exciting field are also been discussed. This timely book shows the readers a complete landscape of hybrid organic-inorganic pervoskites and associated multifuctionalities.
Download or read book Effects of Energetic Disorder on the Optoelectronic Properties of Organic Solar Cells written by Nikolaos Felekidis and published by Linköping University Electronic Press. This book was released on 2018-09-10 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic photovoltaics (OPVs) is a promising low-cost and environmental-friendly technology currently achieving 12-14% power conversion efficiency. Despite the extensive focus of the research community over the last years, critical mechanisms defining the performance of OPVs are still topics of debate. While energetic disorder is known to be characteristic of organic semiconductors in general, its potential role in OPV has received surprisingly little attention. In this thesis we investigate some aspects of the relation between energetic disorder and several optoelectronic properties of OPV. Charge carrier mobility is a key parameter in characterizing the performance of organic semiconductors. Analyzing the temperature dependence of the mobility is also an oftenused method to obtain (estimates for) the energetic disorder in the HOMO and LUMO levels of an organic semiconductor material. Different formalisms to extract and analyze mobilities from space charge limited conductivity (SCLC) experiments are reviewed. Surprisingly, the Murgatroyd-Gill analytical model in combination with the Gaussian disorder model in the Boltzmann limit yields similar mobilities and energetic disorders as a more elaborate drift-diffusion model with parametrized mobility functionals. Common analysis and measurement errors are discussed. All the models are incorporated in an automated analysis freeware tool. The open circuit voltage (Voc) has attracted considerable interest as the large difference between Voc and the bandgap is the main loss mechanism in bulk heterojunction OPVs. Surprisingly, in ternary devices composed of two donors and one acceptor, the Voc is not pinned to the shallowest HOMO but demonstrates a continuous tunability between the binary extremities. We show that this phenomenon can be explained with an equilibrium model where Voc is defined as the splitting of the quasi-Fermi levels of the photo-created holes and electrons in a common density of states accounting for the stoichiometry, i.e. the ratio of the donor materials and the broadening by Gaussian disorder. Evaluating the PCE, it is found that ternary devices do not offer advantages over binary unless the fill factor (FF) is increased at intermediate compositions, as a result of improved transport/recombination upon material blending. Stressing the importance of material intermixing to improve the performance, we found that the presence of an acceptor may drastically alter the mobility and energetic disorder of the donor and vice versa. The effect of different acceptors was studied in a ternary onedonor- two-acceptors system, where the unpredictable variability with composition of the energetic disorder in the HOMO and the LUMO explained the almost linear tunability of Voc. Designing binary OPVs based on the design rule that the energetic disorder can be reduced upon material blending, as we observed, can yield a relative PCE improvement of at least 20%. CT states currently play a key role in evaluating the performance of OPVs and CTelectroluminescence (CT-EL) is assumed to stem from the recombination of thermalized electron-hole pairs. The varying width of the CT-EL peak for different material combinations is intuitively expected to reflect the energetic disorder of the effective HOMO and LUMO. We employ kinetic Monte Carlo (kMC) CT-EL simulations, using independently measured disorder parameters as input, to calculate the ground-to-ground state (0-0) transition spectrum. Including the vibronic broadening according to the Franck Condon principle, we reproduce the width and current dependence of the measured CT-EL peak for a large number of donor-acceptor combinations. The fitted dominant phonon modes compare well with the values measured using the spectral line narrowing technique. Importantly, the calculations show that CT-EL originates from a narrow, non-thermalized subset of all available CT states, which can be understood by considering the kinetic microscopic process with which electron-hole pairs meet and recombine. Despite electron-hole pairs being strongly bound in organic materials, the charge separation process following photo-excitation is found to be extremely efficient and independent of the excitation energy. However, at low photon energies where the charges are excited deep in the tail of the DOS, it is intuitively expected for the extraction yield to be quenched. Internal Quantum Efficiency (IQE) experiments for different material systems show both inefficient and efficient charge dissociation for excitation close to the CT energy. This finding is explained by kinetic Monte Carlo simulations accounting for a varying degree of e-h delocalization, where strongly bound localized CT pairs (< 2nm distance) are doomed to recombine at low excitation energies while extended delocalization over 3-5nm yields an increased and energy-independent IQE. Using a single material parameter set, the experimental CT electroluminescence and absorption spectra are reproduced by the same kMC model by accounting for the vibronic progression of the calculated 0-0 transition. In contrast to CT-EL, CT-absorption probes the complete CT manifold. Charge transport in organic solar cells is currently modelled as either an equilibrium or a non-equilibrium process. The former is described by drift-diffusion (DD) equations, which can be calculated quickly but assume local thermal equilibrium of the charge carriers with the lattice. The latter is described by kMC models, that are time-consuming but treat the charge carriers individually and can probe all relevant time and energy scales. A hybrid model that makes use of the multiple trap and release (MTR) concept in combination with the DD equations is shown to describe both steady-state space charge limited conductivity experiments and non-equilibrium time-resolved transport experiments using a single parameter set. For the investigated simulations, the DD-MTR model is in good agreement with kMC and ~10 times faster. Steady-state mobilities from DD equations have been argued to be exclusively relevant for operating OPVs while charge carrier thermalization and non-equilibrium time-dependent mobilities (although acknowledged) can be disregarded. This conclusion, based on transient photocurrent experiments with ?s time resolution, is not complete. We show that non-equilibrium kMC simulations can describe the extraction of charge carriers from subps to 100 ?s timescales with a single parameter set. The majority of the fast charge carriers, mostly non-thermalized electrons, are extracted at time scales below the resolution of the experiment. In other words, the experiment resolves only the slower fraction of the charges, predominantly holes.
Download or read book Charge Transport and Recombination Dynamics in Organic Bulk Heterojunction Solar Cells written by Andreas Baumann and published by . This book was released on 2011 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
