Photoinduced electron transfer from a conducting polymer to buckminsterfullerene.
27 Nov 1992-Science (American Association for the Advancement of Science)-Vol. 258, Iss: 5087, pp 1474-1476
TL;DR: Because the photoluminescence in the conducting polymer is quenched by interaction with C60, the data imply that charge transfer from the excited state occurs on a picosecond time scale.
Abstract: Evidence for photoinduced electron transfer from the excited state of a conducting polymer onto buckminsterfullerene, C(60), is reported. After photo-excitation of the conjugated polymer with light of energy greater than the pi-pi* gap, an electron transfer to the C(60) molecule is initiated. Photoinduced optical absorption studies demonstrate a different excitation spectrum for the composite as compared to the separate components, consistent with photo-excited charge transfer. A photoinduced electron spin resonance signal exhibits signatures of both the conducting polymer cation and the C(60) anion. Because the photoluminescence in the conducting polymer is quenched by interaction with C(60), the data imply that charge transfer from the excited state occurs on a picosecond time scale. The charge-separated state in composite films is metastable at low temperatures.
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TL;DR: In this paper, the carrier collection efficiency and energy conversion efficiency of polymer photovoltaic cells were improved by blending of the semiconducting polymer with C60 or its functionalized derivatives.
Abstract: The carrier collection efficiency (ηc) and energy conversion efficiency (ηe) of polymer photovoltaic cells were improved by blending of the semiconducting polymer with C60 or its functionalized derivatives. Composite films of poly(2-methoxy-5-(2′-ethyl-hexyloxy)-1,4-phenylene vinylene) (MEH-PPV) and fullerenes exhibit ηc of about 29 percent of electrons per photon and ηe of about 2.9 percent, efficiencies that are better by more than two orders of magnitude than those that have been achieved with devices made with pure MEH-PPV. The efficient charge separation results from photoinduced electron transfer from the MEH-PPV (as donor) to C60 (as acceptor); the high collection efficiency results from a bicontinuous network of internal donor-acceptor heterojunctions.
9,611 citations
TL;DR: This review gives a general introduction to the materials, production techniques, working principles, critical parameters, and stability of the organic solar cells, and discusses the alternative approaches such as polymer/polymer solar cells and organic/inorganic hybrid solar cells.
Abstract: The need to develop inexpensive renewable energy sources stimulates scientific research for efficient, low-cost photovoltaic devices.1 The organic, polymer-based photovoltaic elements have introduced at least the potential of obtaining cheap and easy methods to produce energy from light.2 The possibility of chemically manipulating the material properties of polymers (plastics) combined with a variety of easy and cheap processing techniques has made polymer-based materials present in almost every aspect of modern society.3 Organic semiconductors have several advantages: (a) lowcost synthesis, and (b) easy manufacture of thin film devices by vacuum evaporation/sublimation or solution cast or printing technologies. Furthermore, organic semiconductor thin films may show high absorption coefficients4 exceeding 105 cm-1, which makes them good chromophores for optoelectronic applications. The electronic band gap of organic semiconductors can be engineered by chemical synthesis for simple color changing of light emitting diodes (LEDs).5 Charge carrier mobilities as high as 10 cm2/V‚s6 made them competitive with amorphous silicon.7 This review is organized as follows. In the first part, we will give a general introduction to the materials, production techniques, working principles, critical parameters, and stability of the organic solar cells. In the second part, we will focus on conjugated polymer/fullerene bulk heterojunction solar cells, mainly on polyphenylenevinylene (PPV) derivatives/(1-(3-methoxycarbonyl) propyl-1-phenyl[6,6]C61) (PCBM) fullerene derivatives and poly(3-hexylthiophene) (P3HT)/PCBM systems. In the third part, we will discuss the alternative approaches such as polymer/polymer solar cells and organic/inorganic hybrid solar cells. In the fourth part, we will suggest possible routes for further improvements and finish with some conclusions. The different papers mentioned in the text have been chosen for didactical purposes and cannot reflect the chronology of the research field nor have a claim of completeness. The further interested reader is referred to the vast amount of quality papers published in this field during the past decade.
6,059 citations
TL;DR: In this article, the authors report highly efficient polymer solar cells based on a bulk heterojunction of polymer poly(3-hexylthiophene) and methanofullerene.
Abstract: Converting solar energy into electricity provides a much-needed solution to the energy crisis the world is facing today. Polymer solar cells have shown potential to harness solar energy in a cost-effective way. Significant efforts are underway to improve their efficiency to the level of practical applications. Here, we report highly efficient polymer solar cells based on a bulk heterojunction of polymer poly(3-hexylthiophene) and methanofullerene. Controlling the active layer growth rate results in an increased hole mobility and balanced charge transport. Together with increased absorption in the active layer, this results in much-improved device performance, particularly in external quantum efficiency. The power-conversion efficiency of 4.4% achieved here is the highest published so far for polymer-based solar cells. The solution process involved ensures that the fabrication cost remains low and the processing is simple. The high efficiency achieved in this work brings these devices one step closer to commercialization.
5,431 citations
Cites background from "Photoinduced electron transfer from..."
...The efficiencies of polymer photovoltaic (PV) cells got a major boost with the introduction of the bulk heterojunction (BHJ) concep...
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TL;DR: In this article, the authors presented a review of several organic photovoltaics (OPV) technologies, including conjugated polymers with high-electron-affinity molecules like C60 (as in the bulk-heterojunction solar cell).
Abstract: There has been an intensive search for cost-effective photovoltaics since the development of the first solar cells in the 1950s. [1–3] Among all alternative technologies to silicon-based pn-junction solar cells, organic solar cells could lead the most significant cost reduction. [4] The field of organic photovoltaics (OPVs) comprises organic/inorganic nanostructures like dyesensitized solar cells, multilayers of small organic molecules, and phase-separated mixtures of organic materials (the bulkheterojunction solar cell). A review of several OPV technologies has been presented recently. [5] Light absorption in organic solar cells leads to the generation of excited, bound electron– hole pairs (often called excitons). To achieve substantial energy-conversion efficiencies, these excited electron–hole pairs need to be dissociated into free charge carriers with a high yield. Excitons can be dissociated at interfaces of materials with different electron affinities or by electric fields, or the dissociation can be trap or impurity assisted. Blending conjugated polymers with high-electron-affinity molecules like C60 (as in the bulk-heterojunction solar cell) has proven to be an efficient way for rapid exciton dissociation. Conjugated polymer–C60 interpenetrating networks exhibit ultrafast charge transfer (∼40 fs). [6,7] As there is no competing decay process of the optically excited electron–hole pair located on the polymer in this time regime, an optimized mixture with C60 converts absorbed photons to electrons with an efficiency close to 100%. [8] The associated bicontinuous interpenetrating network enables efficient collection of the separated charges at the electrodes. The bulk-heterojunction solar cell has attracted a lot of attention because of its potential to be a true low-cost photovoltaic technology. A simple coating or printing process would enable roll-to-roll manufacturing of flexible, low-weight PV modules, which should permit cost-efficient production and the development of products for new markets, e.g., in the field of portable electronics. One major obstacle for the commercialization of bulk-heterojunction solar cells is the relatively small device efficiencies that have been demonstrated up to now. [5] The best energy-conversion efficiencies published for small-area devices approach 5%. [9–11] A detailed analysis of state-of-the-art bulk-heterojunction solar cells [8] reveals that the efficiency is limited by the low opencircuit voltage (Voc) delivered by these devices under illumination. Typically, organic semiconductors with a bandgap of about 2 eV are applied as photoactive materials, but the observed open-circuit voltages are only in the range of 0.5–1 V. There has long been a controversy about the origin of the Voc in conjugated polymer–fullerene solar cells. Following the classical thin-film solar-cell concept, the metal–insulator–metal (MIM) model was applied to bulk-heterojunction devices. In the MIM picture, Voc is simply equal to the work-function difference of the two metal electrodes. The model had to be modified after the observation of the strong influence of the reduction potential of the fullerene on the open-circuit volt
4,816 citations
TL;DR: In this paper, a polymer solar cell based on a bulk hetereojunction design with an internal quantum efficiency of over 90% across the visible spectrum (425 nm to 575 nm) is reported.
Abstract: A polymer solar-cell based on a bulk hetereojunction design with an internal quantum efficiency of over 90% across the visible spectrum (425 nm to 575 nm) is reported. The device exhibits a power-conversion efficiency of 6% under standard air-mass 1.5 global illumination tests.
4,002 citations
Cites background from "Photoinduced electron transfer from..."
...69" language="eng" relation="yes" origsrc="yes"> Polymer bulk heterojunction (BHJ) solar cells based on composites of an electron-donating conjugated polymer and an electron-accepting fullerene offer promise for the realization of a low-cost, printable, portable and flexible renewable energy sourc...
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References
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TL;DR: In this article, the authors proposed a truncated icosahedron, a polygon with 60 vertices and 32 faces, 12 of which are pentagonal and 20 hexagonal.
Abstract: During experiments aimed at understanding the mechanisms by which long-chain carbon molecules are formed in interstellar space and circumstellar shells1, graphite has been vaporized by laser irradiation, producing a remarkably stable cluster consisting of 60 carbon atoms. Concerning the question of what kind of 60-carbon atom structure might give rise to a superstable species, we suggest a truncated icosahedron, a polygon with 60 vertices and 32 faces, 12 of which are pentagonal and 20 hexagonal. This object is commonly encountered as the football shown in Fig. 1. The C60 molecule which results when a carbon atom is placed at each vertex of this structure has all valences satisfied by two single bonds and one double bond, has many resonance structures, and appears to be aromatic. Before 1985, it was generally accepted that elemental carbon exists in two forms, or allotropes: diamond and graphite. Then, Kroto et al. identified the signature of a new, stable form of carbon that consisted of clusters of 60 atoms. They called this third allotrope of carbon 'buckminsterfullerene', and proposed that it consisted of polyhedral molecules in which the atoms were arrayed at the vertices of a truncated icosahedron. In 1990, the synthesis of large quantities of C60 [see Nature 347, 354–358 (1990)] confirmed this hypothesis.
13,394 citations
TL;DR: In this article, a new form of pure, solid carbon has been synthesized consisting of a somewhat disordered hexagonal close packing of soccer-ball-shaped C60 molecules.
Abstract: A new form of pure, solid carbon has been synthesized consisting of a somewhat disordered hexagonal close packing of soccer-ball-shaped C60 molecules. Infrared spectra and X-ray diffraction studies of the molecular packing confirm that the molecules have the anticipated 'fullerene' structure. Mass spectroscopy shows that the C70 molecule is present at levels of a few per cent. The solid-state and molecular properties of C60 and its possible role in interstellar space can now be studied in detail.
6,650 citations
Book•
01 Jan 1986
TL;DR: In this paper, the authors presented the theory and properties of conjugated polymers, including transport, optical, and self-assembly properties of poly(3,4-Ethylenedioxythiophene)-polymers.
Abstract: Volume 1: Conjugated Polymers: Theory, Synthesis, Properties, and Characterization PART 1: THEORY OF CONJUGATED POLYMERS On the Transport, Optical, and Self-Assembly Properties of -Conjugated Materials: A Combined Theoretical/Experimental Insight D. Beljonne, J. Cornil, V. Coropceanu, D.A. da Silva Filho, V. Geskin, R. Lazzaroni, P. Leclere, and J.-L. Bredas Theoretical Studies of Electron-Lattice Dynamics in Organic Systems S. Stafstroem PART 2: SYNTHESIS AND CLASSES OF CONJUGATED POLYMERS Helical Polyacetylene Synthesized in Chiral Nematic Liquid Crystals K. Akagi Synthesis and Properties of Poly(arylene vinylene)s A.C. Grimsdale and A.B. Holmes Blue-Emitting Poly(para-Phenylene)-Type Polymers E.J.W. List and U. Scherf Poly(paraPhenyleneethynylene)s and Poly(aryleneethynylene)s: Materials with a Bright Future U.H.F. Bunz Polyaniline Nanofibers: Synthesis, Properties, and Applications J. Huang and R.B. Kaner Recent Advances in Polypyrrole S.H. Cho, K.T. Song, and J.Y. Lee Regioregular Polythiophenes M. Jeffries-El and R.D. McCullough Poly(3,4-Ethylenedioxythiophene)-Scientific Importance, Remarkable Properties, and Applications S. Kirchmeyer, K. Reuter, and J.C. Simpson Thienothiophenes: From Monomers to Polymers G.A. Sotzing, V. Seshadri, and F.J. Waller Low Bandgap Conducting Polymers S.C. Rasmussen and M. Pomerantz Advanced Functional Polythiophenes Based on Tailored Precursors P. Blanchard, P. Leriche, P. Frere, and J. Roncali Structure-Property Relationships and Applications of Conjugated Polyelectrolytes K.S. Schanze and X. Zhao PART 3: PROPERTIES AND CHARACTERIZATION OF CONJUGATED POLYMERS Insulator-Metal Transition and Metallic State in Conducting Polymers A.J. Epstein One-Dimensional Charge Transport in Conducting Polymer Nanofibers A.N. Aleshin and Y.W. Park Structure Studies of - and - Conjugated Polymers M.J. Winokur Electrochemistry of Conducting Polymers P. Audebert and F. Miomandre Internal Fields and Electrode Interfaces in Organic Semiconductor Devices: Noninvasive Investigations via Electroabsorption T.M. Brown and F. Cacialli Electrochromism of Conjugated Conducting Polymers A.L. Dyer and J.R. Reynolds Photoelectron Spectroscopy of Conjugated Polymers M.P. de Jong, G. Greczyniski, W. Osikowicz, R. Friedlein, X. Crispin, M. Fahlman, and W.R. Salaneck Ultrafast Exciton Dynamics and Laser Action in -ConjugatedSemiconductors Z. Valy Vardeny and O. Korovyanko Volume 2: Conjugated Polymers: Processing and Applications PART 1: PROCESSING OF CONJUGATED POLYMERS Conductive Polymers as Organic Nanometals B. Wessling Conducting Polymer Fiber Production and Applications I.D. Norris and B.R. Mattes Inkjet Printing and Patterning of PEDOT-PSS: Application to Optoelectronic Devices Y. Yoshioka and G.E. Jabbour Printing Organic Electronics on Flexible Substrates N.D. Robinson and M. Berggren PART 2: APPLICATIONS AND DEVICES BASED ON CONJUGATED POLYMERS Polymers for Use in Polymeric Light-Emitting Diodes: Structure-Property Relationships H. Christian-Pandya, S. Vaidyanathan, and M. Galvin Organic Electro-Optic Materials L.R. Dalton Conjugated Polymer Electronics-Engineering Materials and Devices N. Tessler, J. Veres, O. Globerman, N. Rappaport, Y. Preezant, Y. Roichman, O. Solomesch, S. Tal, E. Gershman, M. Adler, V. Zolotarev, V. Gorelik, and Y. Eichen Electrical Bistable Polymer Films and Their Applications in Memory Devices J. Ouyang, C.-W. Chu, R.J. Tseng, A. Prakash, and Y. Yang Electroactive Polymers for Batteries and Supercapacitors J.A. Irvin, D.J. Irvin, and J.D. Stenger-Smith Conjugated Polymer-Based Photovoltaic Devices A.J. Mozer and N.S. Sariciftci Biomedical Applications of Inherently Conducting Polymers (ICPs),P.C. Innis, S.E. Moulton, and G.G. Wallace Biosensors Based on Conducting Electroactive Polymers S. Brahim, A.M. Wilson, and A. Guiseppi-Elie Optical Biosensors Based on Conjugated Polymers K. Peter, R. Nilsson, and O. Inganas Conjugated Polymers for Microelectromechanical and Other Microdevices G.M. Spinks and E. Smela Corrosion Protection Using Conducting Polymers D.E. Tallman and G.P. Bierwagen Artificial Muscles T.F. Otero
5,843 citations
TL;DR: In this article, the authors review the theoretical models that have been developed to describe the physics of polyacetylene and related conducting polymers and summarize the relevant experimental results obtained for these materials.
Abstract: Self-localized nonlinear excitations (solitons, polarons, and bipolarons) are fundamental and inherent features of quasi-one-dimensional conducting polymers. Their signatures are evident in many aspects of the physical and chemical properties of this growing class of novel materials. As a result, these polymers represent an opportunity for exploring the novel phenomena associated with topological solitons and their linear confinement which results from weakly lifting the ground-state degeneracy. The authors review the theoretical models that have been developed to describe the physics of polyacetylene and related conducting polymers and summarize the relevant experimental results obtained for these materials. An attempt is made to assess the validity of the soliton model of polyacetylene and its generalization to related systems in which the ground-state degeneracy has been lifted.
2,907 citations
TL;DR: In this paper, a flexible polyethylene terephthalate (PET) based light-emitting diodes (LEDs) were constructed from conjugated polymers, using poly(ethylene-terephthalates) as the substrate, soluble poly-aniline as the hole-injecting electrode, substituted poly(1,4-phenylene-vinylene) as electroluminescent layer and calcium as the electron-injection top contract.
Abstract: THE recent fabrication of light-emitting diodes (LEDs) from conjugated polymers1,2demonstrates the technological potential of this class of electronic materials. A variety of colours are possible, because the wavelength of luminescence emission can be chemically tuned during synthesis1–4. In addition, the mechanical properties of polymers suggest that light-emitting structures can be made that are more flexible than their inorganic counterparts, provided appropriate materials can be found for the substrate and electrodes. Here we report the fabrication of a fully flexible LED using poly(ethylene terephthalate) as the substrate, soluble poly-aniline as the hole-injecting electrode, a substituted poly(1,4-phenylene-vinylene) as the electroluminescent layer and calcium as the electron-injecting top contract. The structure is mechanically robust and may be sharply bent without failure. The LED is easily visible under room lighting and has an external quantum efficiency of about 1%. With a turn-on voltage for light emission of 2–3 V, the 'plastic' LED demonstrates that this unique combination of optical, electrical and mechanical properties can be used to make novel structures that are compatible with conventional devices.
2,513 citations