Download or read book Development and Characterization of New Donor Acceptor Conjugated Polymers and Fullerene Nanoparticles for High Performance Bulk Heterojunction Solar Cells written by and published by . This book was released on 2011 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bithiophene/thieno[3,4-c]pyrrole-4,6-dione (TPD)-based donor-acceptor polymer, PBTTPD, that exhibits high crystallinity and a low-lying highest occupied molecular orbital was prepared. A device incorporating a PBTTPD/[6,6]-phenyl-C61-butyric acid methyl ester blend (1:1.5, w/w) displayed an open circuit voltage of 0.95 V and a power conversion efficiency of 4.7%. A molecular design concept was introduced to develop a series of new conjugated polymers with donor-pi-bridge-acceptor side chains for high-efficiency polymer solar cells. Different from the commonly used linear D-A conjugated polymers, the acceptor of the polymers are located at the end of the side chains and connected with the electron-rich unit on the main chain through a pi-bridge. This method provides a facile way to tune the bandgaps and energy levels of the polymers by simply varying the acceptors on the side chains. A systematic study was performed in this project to elucidate the relationship among molecular structure-morphology-device properties to explore the full potential of applying these new materials for OPV applications.

Download or read book Synthesis and Characterization of Donor acceptor Conjugated Polymers for Bulk Heterojunction Solar Cell Applications written by Mao-Chuan Yuan and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Characterization of Main Chain Donor acceptor Conjugated Polymers for Bulk Heterojunction Solar Cell Applications written by Guan-Yu Chen and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Emerging Photovoltaic Technologies written by Carlito S. Ponseca and published by CRC Press. This book was released on 2019-12-19 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: The need to address the energy problem and formulate a lasting solution to tame climate change has never been so urgent. The rise of various renewable energy sources, such as solar cell technologies, has given humanity a glimpse of hope that can delay the catastrophic effects of these problems after decades of neglect. This review volume provides in-depth discussion of the fundamental photophysical processes as well as the state-of-the-art device engineering of various emerging photovoltaic technologies, including organic (fullerene, non-fullerene, and ternary), dye-sensitized (ruthenium, iron, and quantum dot), and hybrid metal-halide perovskite solar cells. The book is essential reading for graduate and postgraduate students involved in the photophysics and materials science of solar cell technologies.

Download or read book Polymer Photovoltaics written by Fei Huang and published by Royal Society of Chemistry. This book was released on 2015-09-08 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymer solar cells have gained much attention as they offer a potentially economic and viable way of commercially manufacturing lightweight, flexible and low-cost photovoltaics. With contributions from leading scientists, Polymer Photovoltaics provides an international perspective on the latest research for this rapidly expanding field. The book starts with an Introduction to polymer solar cells and covers several important topics that govern their photovoltaic properties including the chemistry and the design of new light harvesting and interfacial materials and their structure-property relationship; the physics for photocurrent generation in the polymer solar cells; new characterization tools to study morphology effect on the property of donor/acceptor bulk heterojunctions; new device concepts such as tandem cells and semi-transparent cells and advanced roll-to-roll processes for large-scale manufacturing of polymer solar cells. Written by active researchers, the book provides a comprehensive overview of the recent advancements in polymer solar cell technology for both researchers and students that are interested in this field.

Download or read book Design Synthesis and Characterization of Self assembling Conjugated Polymers for Use in Organic Electronic Applications written by Kathy Beckner Woody and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Conjugated polymers comprise some of the most promising materials for new technologies such as organic field effect transistors, solar light harvesting technology and sensing devices. In spite of tremendous research initiatives in materials chemistry, the potential to optimize device performance and develop new technologies is remarkable. Understanding relationships between the structure of conjugated polymers and their electronic properties is critical to improving device performance. The design and synthesis of new materials which self-organize into ordered nanostructures creates opportunities to establish relationships between electronic properties and morphology or molecular packing. This thesis details our progress in the development of synthetic routes which provide access to new classes of conjugated polymers that contain dissimilar side chains that segregate or dissimilar conjugated blocks which phase separate, and summarizes our initial attempts to characterize these materials. Poly(1,4-phenylene ethynylene)s (PPEs) have been used in a variety of organic electronic applications, most notably as fluorescent sensors. Using traditional synthetic methods, asymmetrically disubstituted PPEs have irregular placement of side chains on the conjugated backbone. Herein, we establish the first synthetic route to an asymmetrically substituted regioregular PPEs. The initial PPEs in this study have different lengths of alkoxy side chains, and both regioregular and regiorandom analogs are synthesized and characterized for comparison. The design of amphiphilic structures provides additional opportunities for side chains to influence the molecular packing and electronic properties of conjugated polymers. A new class of regioregular, amphiphilic PPEs has been prepared bearing alkoxy and semifluoroalkoxy side chains, which have a tendency to phase separate. Fully conjugated block copolymers can provide access to interesting new morphologies as a result of phase separation of the conjugated blocks. In particular, donor-acceptor block copolymers that phase separate into electron rich and electron poor domains may be advantageous in organic electronic devices such as bulk heterojunction solar cells, of which the performance relies on precise control of the interface between electron donating and accepting materials. The availability of donor-acceptor block copolymers is limited, largely due to the challenges associated with synthesizing these materials. In this thesis, two new synthetic routes to donor-acceptor block copolymers are established. These methods both utilize the catalyst transfer condensation polymerization, which proceeds by a chain growth mechanism. The first example entails the synthesis of a monofunctionalized, telechelic poly(3-alkylthiophene) which can be coupled to electron accepting polymers in a subsequent reaction. The other method describes the first example of a one-pot synthesis of a donor-acceptor diblock copolymer. The methods of synthesis are described, and characterization of the block copolymers is reported.

Download or read book Synthesis and Characterisation of Non Fullerene Electron Acceptors for Organic Photovoltaics written by Sarah Holliday and published by Springer. This book was released on 2018-03-22 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reports on the design, synthesis and characterization of new small molecule electron acceptors for polymer solar cells. Starting with a detailed introduction to the science behind polymer solar cells, the author then goes on to review the challenges and advances made in developing non-fullerene acceptors so far. In the main body of the book, the author describes the design principles and synthetic strategy for a new family of acceptors, including detailed synthetic procedures and molecular modeling data used to predict physical properties. An indepth characterization of the photovoltaic performance, with transient absorption spectroscopy (TAS), photo-induced charge extraction, and grazing incidence X-ray diffraction (GIXRD) is also included, and the author uses this data to relate material properties and device performance. This book provides a useful overview for researchers beginning a project in this or related areas.

Download or read book Synthesis and Characterization of Conjugated Polymers and Small Molecules for Organic Photovoltaic Devices written by Obum Kwon and published by . This book was released on 2013 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: Solar energy harvested directly from sunlight using photovoltaic (PV) technology has become one of the most promising ways to meet growing global energy needs with a sustainable resource while minimizing environmental concerns. Especially, organic bulk heterojunction (BHJ) solar cells have been attracting a great deal of interest as a source of renewable energy because of their potential as low-cost, flexible, light-weight and large-scale devices. The choice of materials in a BHJ solar cell is very important for device performance because the power conversion efficiencies (PCEs) are determined by their some crucial characteristics such as energy levels, charge transfer mobilities and structural orders. In this dissertation, two carbazole-diketopyrrolopyrrole based conjugated polymers (P1 and P2) and three thieno-[3,4-c]pyrrole-4,6-dione (TPD) based small molecules (M1, SM1 and SM2) were synthesized and characterized to investigate their optical, electrical and photovoltaic properties. First, the substitution of alkyl and aryl side chains on the carbazole moiety of two push-pull conjugated polymers (P1 and P2) shows the significant differences in the optical, electrical and photovoltaic properties. Second, TPD-based conjugated small molecule with a donor-acceptor-donor-acceptor-donor (D-A-D-A-D) framework, M1 shows the relatively deep HOMO level resulting the relatively high Voc.(0.85 eV) Small molecule BHJ solar cells were fabricated and characterized using different M1:PC71BM blend ratios, solvents, and additives and the highest PCE achieved in this study was 1.86%. Lastly, different bridgehead atoms of SM1 and SM2 can affect their energy band levels and device performances. The PCE (2.5%) of the SM2-based SM-BHJ solar cell was higher than that of the SM1-based SM-BHJ solar cell (1.5%).

Download or read book Polymer Based Nanostructured Donor Acceptor Heterojunction Photovoltaic Devices written by and published by . This book was released on 2003 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bulk heterojunction photovoltaic devices based on blends of conjugated polymers and fullerenes have achieved efficiencies of 3.5% under AM1.5 illumination. This is a result of efficient exciton dissociation at donoracceptor interfaces. However, the intimate blending of the electron and hole transporting species leads to detrimental charge carrier recombination in the bulk of these devices. We are investigating a solution to this problem by fabricating nanostructured oxideconjugated polymer composite structures. Porous SnO2 films with pore diameters of~100 nm have been fabricated. Intercalation of polymers into the pores by adsorption from solution yielded structures with approximately 75% of the free volume filled with polymer. The resulting composite structures are promising candidates for developing polymer-based solar cells with short carrier-to-electrode path lengths while retaining high optical absorption, thus leading to increased efficiencies. Additionally, a carboxylic acid fullerene derivative was shown to bind to the SnO2 surface, a necessary step in creating a nanostructured electron-accepting surface.

Download or read book Synthesis and Characterization of New Conjugated Polymers for Application in Solar Cells written by Mohd Sani Sarjadi and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Charge transfer and Other Excitonic State in Conjugated Polymer written by Dhanashree Moghe and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the last few decades there has been tremendous progress in organic photovoltaics (OPVs), with efficiencies reaching over 10%. Still, many factors including the origin and the dynamics of charge carrier involved are debatable. New and sensitive techniques are constantly being devised to identify the origin of free charges. At the same time, a lot of research has also been devoted to synthesize low bandgap material such that its absorption spectra overlap with that of the solar spectrum. The most important hindrance in organic semiconductors is the formation of bound electron-hole (exciton) charge pair upon photoexcitation. Additional energy is required to dissociate the bound pair to generate free charges for photovoltaic application. The most popular and efficient way to dissociate excitons is to fabricate a bulk heterojunction solar cell, which comprises of a blend of at least two polymers: one donor and the other acceptor. It is very well established that the presence of fullerene (acceptor) helps in transfer of the negative charges from the donor polymer to fullerene, making the exciton slightly less bound. The nanometer scale islands further help in migration of charges. A crucial aspect of our studies has been evaluating the role of various excitonic states such as charge-transfer and triplet excitonic states in device efficiencies. The focus of this work was on diketopyrrolopyrrole (DPP)- based donor-acceptor (D-A) type conjugated copolymers which have low bandgap energies and have been known to show high efficiency in organic photovoltaics. These copolymers have D-A unit present in the same chain, which lowers the optical bandgap of the material. Variation of either the donor or the acceptor fraction offers an option to tune the optical bandgap by using the same D-A chromophores. The D-A configuration also results in the separation of positive and negative charges within the same polymeric chain, which is the intramolecular charge-transfer excitonic state. We analyze the intramolecular charge-transfer state using bias dependent absorption studies, which allowed us to estimate the binding energy of intramolecular exciton. Later, we performed density functional theory (DFT) and time dependent DFT calculations to identify the origin of the intramolecular exciton absorption. Taking the copolymers as donor (and fullerene as acceptor) in an organic photovoltaic device, we probe the (intermolecular) charge-transfer states formed at the copolymer/fullerene interface . We utilize monochromatic photocurrent method and a highly sensitive (and fast) Fourier transform photocurrent spectroscopy technique to probe the intermolecular charge-transfer states in the device. Our analyses show that the optical bandgap difference between the copolymers and fullerene plays a pivotal role in stabilization /destabilization of charge - transfer states in copolymer-fullerene systems. The triplet excitons are also known to play an important role in OPV efficiency. We probe the diffusion length of triplet exciton in ladder-type polymers by devising a simple, yet efficient method using optical modulation spectroscopy (photoinduced absorption spectroscopy). The diffusion length of triplet excitons is estimated to be almost three orders of magnitude more than the singlet excitons . Further, by implementing a 1D random-walk model to the photoinduced absorption data, we estimate diffusivities of the triplet exciton in our sample.

Download or read book Novel Acceptor Molecules for Bulk Heterojunction Organic Solar Cells written by Jason Thomas Bloking and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Solution-processable organic solar cells offer the promise of clean energy generation at lower cost than conventional technologies due to high-throughput roll-to-roll manufacturing, cheap and abundant materials and the lower installation costs associated with lightweight and flexible solar modules. Power conversion efficiencies of organic solar cells have surpassed 10% due in large part to the discovery and design of new materials for the donor half of the donor-acceptor heterojunction. However, the vast majority of organic photovoltaic devices contain fullerene derivatives as the electron acceptor material. Devices containing fullerenes as the electron acceptors have been shown to be energetically limited to open-circuit voltages of 1.0 V or less, thus limiting their maximum efficiency and potential for use as the high-voltage top cell in tandem solar cell architectures. This is in addition to other drawbacks of fullerenes such as their high synthetic cost and relatively poor light absorption. A phenyl imide-based electron acceptor molecule, HPI-BT, has been developed as an alternative to fullerene derivatives to address some of these drawbacks. Device efficiencies of up to 3.7% with the common electron donating polymer poly (3-hexyl thiophene) -- P3HT -- have been achieved through detailed optimization. While these devices have open-circuit voltages of 0.94 V (0.31 V higher than comparable devices with P3HT and PC61BM, a common fullerene derivative), the quantum efficiency is 20% lower than the equivalent fullerene-containing device. Through investigation of the dependence of quantum efficiency on applied electric field and light intensity in these devices and others using additional electron donating polymers, the primary cause of lower quantum efficiency in these devices is found to be recombination of geminate charge pairs before they are able to reach their fully charge-separated state. Recent research reports show that the microstructure of a typical bulk heterojunction organic solar cell consists of a relatively pure electron donor phase (P3HT), a relatively pure acceptor phase (PC61BM) and a two-component mixed phase at the interface of the two pure phases. This interfacial mixed phase is believed to provide an energetic driving force for charge separation from the mixed phase into the pure phases, thus providing high quantum efficiencies in fullerene-based devices. X-ray diffraction studies on blends of polythiophene and HPI-BT show no evidence of a strongly mixed third phase. The lower quantum efficiency of devices containing HPI-BT without this third mixed phase is explained by the favorable energetic offsets created in this three-phase morphology. Alternatively, the inability of fullerenes to effectively absorb light can be partially mitigated by the addition of a third molecule providing additional absorption bandwidth in a ternary blend organic solar cell. The addition of up to 20% (by weight) of a conjugated dye molecule, tetra-tert-butyl functionalized silicon naphthalocyanine (t-butyl SiNc), to a typical bulk heterojunction solar cell with P3HT and PC61BM results in the generation of additional photocurrent from dye absorption in the near-infrared region of the light spectrum. The effect of the tert-butyl functionalization on the incorporation of the dye molecule is discussed along with the potential for improved efficiency of ternary blend organic solar cells relative to their binary blend counterparts.

Download or read book Conjugated Polymers for Next Generation Applications Volume 2 written by Vijay Kumar and published by Woodhead Publishing. This book was released on 2022-06-23 with total page 443 pages. Available in PDF, EPUB and Kindle. Book excerpt: Conjugated Polymers for Next-Generation Applications, Volume Two: Energy Storage Devices describes the synthesis and characterization of varied conjugated polymeric materials and their key applications, including active electrode materials for electrochemical capacitors and lithium-ion batteries, along with new ideas of functional materials for next-generation high-energy batteries, a discussion of common design procedures, and the pros and cons of conjugated polymers for certain applications. The book's emphasis lies in the underlying electronic properties of conjugated polymers, their characterization and analysis, and the evaluation of their effectiveness for utilization in energy and electronics applications. This book is ideal for researchers and practitioners in the area of materials science, chemistry and chemical engineering. - Provides an overview of the synthesis and functionalization of conjugated polymers and their composites - Reviews important photovoltaics applications of conjugated polymeric materials, including their use in energy storage, batteries and optoelectronic devices - Discusses conjugated polymers and their application in electronics for sensing, bioelectronics, memory, and more

Download or read book Generation Recombination and Extraction of Charges in Polymer written by Steve Albrecht and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A dramatic efficiency improvement of bulk heterojunction solar cells based on electron-donating conjugated polymers in combination with soluble fullerene derivatives has been achieved over the past years. Certified and reported power conversion efficiencies now reach over 9% for single junctions and exceed the 10% benchmark for tandem solar cells. This trend brightens the vision of organic photovoltaics becoming competitive with inorganic solar cells including the realization of low-cost and large-area organic photovoltaics. For the best performing organic materials systems, the yield of charge generation can be very efficient. However, a detailed understanding of the free charge carrier generation mechanisms at the donor acceptor interface and the energy loss associated with it needs to be established. Moreover, organic solar cells are limited by the competition between charge extraction and free charge recombination, accounting for further efficiency losses. A conclusive picture and the development of precise methodologies for inves...

Download or read book Conjugated Polymers and DNA for Photovoltaic and Photonic Applications written by Palamu Arachchige Daminda Sampath Navarathne and published by . This book was released on 2011 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Rational Design of Ternary Blend Organic Solar Cells Based on Block Copolymer Additives written by Dylan Robb Kipp and published by . This book was released on 2016 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt: We utilize a combined computational and experimental approach to study the influence of block copolymer additives on the morphological and device characteristics of organic solar cells based on the conjugated polymer/fullerene bulk heterojunction morphology. Our study is motivated by the question whether such block copolymer additives can be utilized to influence the phase separation morphologies, interfacial properties, and, therefore, the device efficiencies of such organic photovoltaic devices. Towards this objective, we split our project into 3 parts: 1.) We utilize Single Chain in Mean Field simulations to investigate the influence of block copolymers on the morphological and interfacial characteristics of the polymer/fullerene blend. Based on these simulations, we identify a design rule for the formation of the equilibrium, cocontinuous donor/acceptor morphologies that are believed to be desirable for efficient charge collection in organic photovoltaics. We utilize this design rule to identify a large collection of blend formulations that give rise to bicontinuous phases, and identify which of these select blend formulations result from comparable volume mixtures of donors and acceptors, which typically yield high device efficiencies in organic photovoltaics. 2.) Based on the predictions from (1), in experiments, we design thermally-stable morphologies with nanoscale domain sizes and percolating donor/acceptor pathways. We demonstrate the manner in which the experimental results agree with the simulations and, hence, establish the validity of our simulation method for predicting phase behavior. 3.) We develop a kinetic Monte Carlo-based method to predict the device performance characteristics of arbitrary donor/acceptor morphologies and couple the morphology and device-level simulations in sequence to identify the blend formulations and resulting morphological features that give rise to the best device performance overall. We demonstrate that, by appropriately tuning the HOMO and LUMO energy levels of the block copolymer additive, an energy cascade can be exploited to further improve charge separation and device efficiencies. In total, our project constitutes a predictive framework for designing new additive-based organic photovoltaic blend formulations with optimized device properties.

Download or read book Conjugated Polymers for Next Generation Applications Volume 1 written by Vijay Kumar and published by Woodhead Publishing. This book was released on 2022-06-24 with total page 618 pages. Available in PDF, EPUB and Kindle. Book excerpt: Conjugated Polymers for Next-Generation Applications, Volume One: Synthesis, Properties and Optoelectrochemical Devices describes the synthesis and characterization of varied conjugated polymeric materials and their key applications, including active electrode materials for electrochemical capacitors and lithium-ion batteries, along with new ideas of functional materials for next-generation high-energy batteries, a discussion of common design procedures, and the pros and cons of conjugated polymers for certain applications. The book's emphasis lies in the underlying electronic properties of conjugated polymers, their characterization and analysis, and the evaluation of their effectiveness for utilization in energy and electronics applications. This book is ideal for researchers and practitioners in the area of materials science, chemistry and chemical engineering. - Provides an overview of the synthesis and functionalization of conjugated polymers and their composites - Reviews important photovoltaics applications of conjugated polymeric materials, including their use in energy storage, batteries and optoelectronic devices - Discusses conjugated polymers and their application in electronics for sensing, bioelectronics, memory, and more