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...
Citations
More filters
TL;DR: The photoluminescence intensity of ZnS-AgInS(2) solid solution nanoparticles was remarkably enhanced by increasing the heating temperature to 180 degrees C, above which the emission was simply diminished, while ZNS coating of the particles resulted in further enhancement of PL intensity, giving the highest quantum yield.
148 citations
TL;DR: The novel synthesis of tetrahedrite copper antimony sulfide (CAS) nanocrystals (Cu12Sb4S13), which display strong absorptions in the visible and NIR, are presented, an excellent new candidate for both thin film and hybrid solar cells and as strong NIR absorbers in general.
Abstract: Herein, we present the novel synthesis of tetrahedrite copper antimony sulfide (CAS) nanocrystals (Cu12Sb4S13), which display strong absorptions in the visible and NIR. Through ligand tuning, the size of the Cu12Sb4S13 NCs may be increased from 6 to 18 nm. Phase purity is achieved through optimizing the ligand chemistry and maximizing the reactivity of the antimony precursor. We provide a detailed investigation of the optical and photoelectrical properties of both tetrahedrite (Cu12Sb4S13) and famatinite (Cu3SbS4) NCs. These NCs were found to have very high absorption coefficients reaching 105 cm–1 and band gaps of 1.7 and 1 eV for tetrahedrite and famatinite NCs, respectively. Ultraviolet photoelectron spectroscopy was employed to determine the band positions. In each case, the Fermi energies reside close to the valence band, indicative of a p-type semiconductor. Annealing of tetrahedrite CAS NC films in sulfur vapor at 350 °C was found to result in pure famatinite NC films, opening the possibility to tu...
148 citations
TL;DR: A robust S(2-)/S(n)(2-) electrolyte that has been specifically designed for compatibility with CdSe quantum dots in sensitized solar cells is reported, which reaches 1.86% efficiency and a short-circuit current close to 14 mA·cm(-2) under air-mass 1.5 global illumination.
Abstract: Further development of quantum dot-sensitized solar cells (QDSCs) will require long-term stability in addition to the continuous increase of photovoltaic (PV) conversion efficiency achieved in the last years. We report a robust S2–/Sn2– electrolyte that has been specifically designed for compatibility with CdSe quantum dots in sensitized solar cells. The new pyrrolidinium ionic liquid reaches 1.86% efficiency and a short-circuit current close to 14 mA·cm–2 under air-mass 1.5 global illumination and improves the device lifetime with good photoanode stability over 240 h. PV characterization showed that the solar cell limitations relate to poor catalysis of regeneration at the counter electrode and high recombination. Further improvement of these factors in the robust electrolyte configuration may thus have a significant impact for advancing the state-of-the-art in QDSCs.
148 citations
TL;DR: In this article, the surface modification of solution-based quantum dot-sensitized solar cells (QDSCs) via the steady state absorption and emission characteristics of colloidal CdSe passivated with β-alanine (β-Ala) was studied.
Abstract: With the increased interest in quantum dot sensitized solar cells (QDSCs) there comes a need to better understand how surface modification of quantum dots (QDs) can affect the excited state dynamics of QDs, electron transfer at the QD–metal oxide (MO) interface, and overall photoconversion efficiency of QDSCs. We have monitored the surface modification of solution based QDs via the steady state absorption and emission characteristics of colloidal CdSe passivated with β-alanine (β-Ala). The trap-remediating nature of the β-Ala molecule, arising from the Lewis basicity of the amine group, is realized from the hypsochromic shifts seen in excitonic absorption and emission bands as well as an increase in fluorescence quantum yield. Transient absorption measurements of CdSe–TiO2 films prepared with and without β-Ala as a linker molecule further reveal the role of the surface modifier in influencing excited state electron transfer processes. Electron transfer at this interface was found to be dependent on the me...
146 citations
01 Oct 2018
TL;DR: In this paper, an interesting, new 0D material is presented: graphene quantum dots The new properties arising from quantum confinement and edge effects after converting 2D graphene into graphene quantum dot have attracted great interest in various disciplines, such as physics, biology, materials, and chemistry.
Abstract: Here, an interesting, new 0D material is presented: graphene quantum dots The new properties arising from quantum confinement and edge effects after converting 2D graphene into graphene quantum dots have attracted great interest in various disciplines, such as physics, biology, materials, and chemistry Here, the recent technological advances in the field of graphene quantum dots reported in the literature on both a theoretical and an experimental basis are highlighted Various synthesis methodologies and physical properties are discussed, along with their implementation in energy (supercapacitors, fuel cells, photovoltaic devices, light-emitting diodes), biomedical (biosensors, drug delivery, bioimaging), and environmental applications
146 citations
References
More filters
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