Quantum Dot Solar Cells. Semiconductor Nanocrystals as Light Harvesters
18 Oct 2008-Journal of Physical Chemistry C (American Chemical Society)-Vol. 112, Iss: 48, pp 18737-18753
TL;DR: In this paper, three major ways to utilize semiconductor dots in solar cell include (i) metal−semiconductor or Schottky junction photovoltaic cell, (ii) polymer−smiconductor hybrid solar cell, and (iii) quantum dot sensitized solar cell.
Abstract: The emergence of semiconductor nanocrystals as the building blocks of nanotechnology has opened up new ways to utilize them in next generation solar cells. This paper focuses on the recent developments in the utilization of semiconductor quantum dots for light energy conversion. Three major ways to utilize semiconductor dots in solar cell include (i) metal−semiconductor or Schottky junction photovoltaic cell (ii) polymer−semiconductor hybrid solar cell, and (iii) quantum dot sensitized solar cell. Modulation of band energies through size control offers new ways to control photoresponse and photoconversion efficiency of the solar cell. Various strategies to maximize photoinduced charge separation and electron transfer processes for improving the overall efficiency of light energy conversion are discussed. Capture and transport of charge carriers within the semiconductor nanocrystal network to achieve efficient charge separation at the electrode surface remains a major challenge. Directing the future resear...
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TL;DR: In this paper, the authors present the synthesis of 1D nanostructured fibers made via electrospinning and their applications in photovoltaics, photocatalysis, hydrogen energy harvesting and fuel cells.
Abstract: As the demand for energy is rapidly growing worldwide ahead of energy supply, there is an impulse need to develop alternative energy-harvesting technologies to sustain economic growth. Due to their unique optical and electrical properties, one-dimensional (1D) electrospun nanostructured materials are attractive for the construction of active energy harvesting devices such as photovoltaics, photocatalysts, hydrogen energy generators, and fuel cells. 1D nanostructures produced from electrospinning possess high chemical reactivity, high surface area, low density, as well as improved light absorption and dye adsorption compared to their bulk counterparts. So, research has been focused on the synthesis of 1D nanostructured fibers made from metal oxides, composites, dopants and surface modification. Furthermore, fine tuning these NFs has facilitated fast charge transfer and efficient charge separation for improved light absorption in photocatalytic and photovoltaic properties. The recent trend in exploring these electrospun nanostructures has been promising in-terms of reducing costs and enhancing the efficiency compared to conventional materials. This review article presents the synthesis of 1D nanostructured fibers made via electrospinning and their applications in photovoltaics, photocatalysis, hydrogen energy harvesting and fuel cells. The current challenges and future perspectives for electrospun nanomaterials are also reviewed.
252 citations
TL;DR: It is shown that it is possible to design both injection and recombination in QD sensitized solar cells (QDSCs) by the appropriate use of molecular dipoles and conformal coatings by boosting the energy conversion efficiency of the devices.
Abstract: Semiconductor Quantum Dots (QDs) currently receive widespread attention for the development of photovoltaic devices due to the possibility of tailoring their optoelectronic properties by the control of size and composition. Here we show that it is possible to design both injection and recombination in QD sensitized solar cells (QDSCs) by the appropriate use of molecular dipoles and conformal coatings. QDSCs have been manufactured using mesoporous TiO2 electrodes coated with “in situ” grown CdSe semiconductor nanocrystals by chemical bath deposition (CBD). Surface modification of the CdSe sensitized electrodes by conformal ZnS coating and grafting of molecular dipoles (DT) has been explored to both increase the injection from QDs into the TiO2 matrix and reduce the recombination of the QD sensitized electrodes. Different sequences of both treatments have been tested aiming at boosting the energy conversion efficiency of the devices. The obtained results showed that the most favorable sequence of the surfac...
252 citations
TL;DR: Bi(2)S(3) nanocrystals/BiOCl hybrid architectures with tunable band gaps were synthesized by a controlled anion exchange approach and they displayed highly efficient visible light photoactivities, which is associated with suitable energetics and structural topotactic relationship that can benefit the interfacial charge transfer.
247 citations
TL;DR: A nearly three-fold increase in the photoconversion efficiency (IPCE) was observed upon intercalation of Li(+) ions into TiO(2) nanotube arrays and the analysis of the V(oc) decay following termination of UV light shows a significant decrease in the rate of recombination of accumulated electrons.
Abstract: Cations such as H(+) and Li(+) are intercalated into TiO(2) nanotube arrays by subjecting them to short-term electrochemical pulses at controlled potentials (<-1.0 V vs Ag/AgCl). The intercalation of these small cations has a profound effect toward enhancing photocurrent generation under UV light irradiation. A nearly three-fold increase in the photoconversion efficiency (IPCE) was observed upon intercalation of Li(+) ions into TiO(2) nanotube arrays. The intercalation process is visualized by the color change from gray to blue. Spectroelectrochemical measurements were carried out to monitor the absorption changes at different applied potentials. The analysis of the V(oc) decay following termination of UV light shows a significant decrease in the rate of recombination of accumulated electrons upon Li(+) ion intercalation.
246 citations
Cites methods from "Quantum Dot Solar Cells. Semiconduc..."
...T iO2 nanotube arrays prepared by anodic corrosion of Ti films are useful as 1-D scaffolds to anchor lightharvesting assemblies.(1) 4 These TiO2 nanotube arrays consist of 50 100 nm diameter...
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TL;DR: The use of narrow band gap semiconductors such as PbS may expand the light absorption range to the near-infrared region in quantum-dot-sensitized solar cells.
Abstract: The use of narrow band gap semiconductors such as PbS may expand the light absorption range to the near-infrared region in quantum-dot-sensitized solar cells (QDSCs), increasing the generated photo...
246 citations
References
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TL;DR: In this article, an upper theoretical limit for the efficiency of p−n junction solar energy converters, called the detailed balance limit of efficiency, has been calculated for an ideal case in which the only recombination mechanism of holeelectron pairs is radiative as required by the principle of detailed balance.
Abstract: In order to find an upper theoretical limit for the efficiency of p‐n junction solar energy converters, a limiting efficiency, called the detailed balance limit of efficiency, has been calculated for an ideal case in which the only recombination mechanism of hole‐electron pairs is radiative as required by the principle of detailed balance. The efficiency is also calculated for the case in which radiative recombination is only a fixed fraction fc of the total recombination, the rest being nonradiative. Efficiencies at the matched loads have been calculated with band gap and fc as parameters, the sun and cell being assumed to be blackbodies with temperatures of 6000°K and 300°K, respectively. The maximum efficiency is found to be 30% for an energy gap of 1.1 ev and fc = 1. Actual junctions do not obey the predicted current‐voltage relationship, and reasons for the difference and its relevance to efficiency are discussed.
11,071 citations
TL;DR: Many potential applications have been proposed for carbon nanotubes, including conductive and high-strength composites; energy storage and energy conversion devices; sensors; field emission displays and radiation sources; hydrogen storage media; and nanometer-sized semiconductor devices, probes, and interconnects.
Abstract: Many potential applications have been proposed for carbon nanotubes, including conductive and high-strength composites; energy storage and energy conversion devices; sensors; field emission displays and radiation sources; hydrogen storage media; and nanometer-sized semiconductor devices, probes, and interconnects. Some of these applications are now realized in products. Others are demonstrated in early to advanced devices, and one, hydrogen storage, is clouded by controversy. Nanotube cost, polydispersity in nanotube type, and limitations in processing and assembly methods are important barriers for some applications of single-walled nanotubes.
9,693 citations
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: In this paper, the authors describe recent progress in the theory of nanoparticle optical properties, particularly methods for solving Maxwell's equations for light scattering from particles of arbitrary shape in a complex environment.
Abstract: The optical properties of metal nanoparticles have long been of interest in physical chemistry, starting with Faraday's investigations of colloidal gold in the middle 1800s. More recently, new lithographic techniques as well as improvements to classical wet chemistry methods have made it possible to synthesize noble metal nanoparticles with a wide range of sizes, shapes, and dielectric environments. In this feature article, we describe recent progress in the theory of nanoparticle optical properties, particularly methods for solving Maxwell's equations for light scattering from particles of arbitrary shape in a complex environment. Included is a description of the qualitative features of dipole and quadrupole plasmon resonances for spherical particles; a discussion of analytical and numerical methods for calculating extinction and scattering cross-sections, local fields, and other optical properties for nonspherical particles; and a survey of applications to problems of recent interest involving triangula...
9,086 citations
TL;DR: Semiconductor nanocrystals prepared for use as fluorescent probes in biological staining and diagnostics have a narrow, tunable, symmetric emission spectrum and are photochemically stable.
Abstract: Semiconductor nanocrystals were prepared for use as fluorescent probes in biological staining and diagnostics. Compared with conventional fluorophores, the nanocrystals have a narrow, tunable, symmetric emission spectrum and are photochemically stable. The advantages of the broad, continuous excitation spectrum were demonstrated in a dual-emission, single-excitation labeling experiment on mouse fibroblasts. These nanocrystal probes are thus complementary and in some cases may be superior to existing fluorophores.
8,542 citations