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: The systematic study of PbS-sensitized solar cells utilizing different metal oxide semiconductors as electron transporters would provide useful insights and promote the development of semiconductor-s Sensitized mesoscopic solar cells employing panchromatic sensitizers.
Abstract: Metal oxide semiconductors with lower lying conduction band minimum and superior electron mobility are essential for efficient charge separation and collection in PbS-sensitized solar cells. In the present study, mesoscopic SnO2 was investigated as an alternative photoanode to the commonly used TiO2 and examined comprehensively in PbS-sensitized liquid junction solar cells. To exploit the capability of PbS in an optimized structure, cascaded nPbS/nCdS and alternate n(PbS/CdS) layers deposited by a successive ionic layer adsorption and reaction method were systematically scrutinized. It was observed that the surface of SnO2 has greater affinity to the growth of PbS compared with TiO2, giving rise to much enhanced light absorption. In addition, the deposition of a CdS buffer layer and a ZnS passivation layer before and after a PbS layer was found to be beneficial for efficient charge separation. Under optimized conditions, cascaded PbS/CdS-sensitized SnO2 exhibited an unprecedented photocurrent density of 17.38 mA cm−2 with pronounced infrared light harvesting extending beyond 1100 nm, and a power conversion efficiency of 2.23% under AM 1.5, 1 sun illumination. In comparison, TiO2 cells fabricated under similar conditions showed much inferior performance owing to the less efficient light harnessing of long wavelength photons. We anticipate that the systematic study of PbS-sensitized solar cells utilizing different metal oxide semiconductors as electron transporters would provide useful insights and promote the development of semiconductor-sensitized mesoscopic solar cells employing panchromatic sensitizers.
58 citations
TL;DR: The findings reported herein suggest that the atomic inorganic ligand reinforces the influence of quantum confinement on the solar energy conversion efficiency of QDSSCs.
Abstract: Light absorption and electron injection are important criteria determining solar energy conversion efficiency. In this research, monodisperse CdSe quantum dots (QDs) are synthesized with five different diameters, and the size-dependent solar energy conversion efficiency of CdSe quantum dot sensitized solar cell (QDSSCs) is investigated by employing the atomic inorganic ligand, S2–. Absorbance measurements and transmission electron microscopy show that the diameters of the uniform CdSe QDs are 2.5, 3.2, 4.2, 6.4, and 7.8 nm. Larger CdSe QDs generate a larger amount of charge under the irradiation of long wavelength photons, as verified by the absorbance results and the measurements of the external quantum efficiencies. However, the smaller QDs exhibit faster electron injection kinetics from CdSe QDs to TiO2 because of the high energy level of CBCdSe, as verified by time-resolved photoluminescence and internal quantum efficiency results. Importantly, the S2– ligand significantly enhances the electronic coup...
58 citations
TL;DR: In this article, a comprehensive review on recent advances in electrolytes for QDSCs, with a conclusion and future prospects section, is presented, where the authors focus on the electrolyte system.
Abstract: Quantum dot sensitized solar cells (QDSCs) have been considered as a promising candidate for low-cost, high efficiency third generation photovoltaic solar cells. In the past few years, QDSCs have witnessed tremendous progress with an increase of power conversion efficiency from less than 5% in 2010 to 12.57% in 2017. Both photoanodes and counter electrodes for QDSCs have been extensively studied and reviewed in previous reports, while little attention has been paid to the electrolyte system. Herein, we present a comprehensive review on recent advances in electrolytes for QDSCs, with a conclusion and future prospects section.
58 citations
TL;DR: The hemin/G-quadruplex-catalyzed generation of chemiluminescence through the oxidation of luminol by H2O2 stimulates the chemilUMinescence resonance energy transfer to CdSe/ZnS quantum dots (QDs), resulting in the luminescence of the QDs.
Abstract: The hemin/G-quadruplex-catalyzed generation of chemiluminescence through the oxidation of luminol by H2O2 stimulates the chemiluminescence resonance energy transfer (CRET) to CdSe/ZnS quantum dots (QDs), resulting in the luminescence of the QDs. By the cyclic K+-ion-induced formation of the hemin/G-quadruplex linked to the QDs, and the separation of the G-quadruplex in the presence of 18-crown-6-ether, the ON-OFF switchable CRET-induced luminescence of the QDs is demonstrated. QDs were modified with nucleic acids consisting of the G-quadruplex subunits sequences and of programmed domains that can be cross-linked through hybridization, using an auxiliary scaffold. In the presence of K+-ions, the QDs aggregate through the cooperative stabilization of K+-ion-stabilized G-quadruplex bridges and duplex domains between the auxiliary scaffold and the nucleic acids associated with the QDs. In the presence of 18-crown-6-ether, the K+-ions are eliminated from the G-quadruplex units, leading to the separation of the...
58 citations
TL;DR: In this article, CdS/CdSe co-sensitized TiO 2 photoanodes for QDSSCs were prepared by successive ionic layer adsorption and reaction (SILAR), spray pyrolysis and zinc-copper alloy processes.
Abstract: Herein, CdS/CdSe co-sensitized TiO 2 photoanodes for QDSSCs were prepared by successive ionic layer adsorption and reaction (SILAR), spray pyrolysis and zinc–copper alloy processes. The HR-TEM, SEM, EDS, XRD, UV–vis and I – V curve analyses were performed to investigate the surface and structural properties of the prepared electrodes and the efficiencies of the fabricated QDSSs. Employing different methods for preparation of Cu 2 S counter electrode affected the performance of QDSSCs under one illumination of sun (100 mW/cm 2 ) so that various conversion efficiencies ( μ ) of 3.18, 0.341 and 0.266% were measured in alloy, SILAR and spray pyrolysis methods, respectively. Therefore, among these methods, the zinc–copper alloy process with higher efficiency is preferred that gives fill factor (ff) and short circuit density ( J SC ) values of 0.44 and 11.69 mA/cm 2 . The HR-TEM images showed that CdS and CdSe QDs are in close contact with TiO 2 nanoparticles and the sizes of CdS and CdSe QDs are about 5 and 6 nm, respectively. The energy-dispersive X-ray spectroscopy (EDS) measurement confirmed that CdS and CdSe QDs are successfully deposited on the surface of the TiO 2 film. The band gaps estimated from Tauc plots using UV–vis spectra vary from 3.1 eV (without CdS and CdSe, bare TiO 2 ) to 2.38 eV (TiO 2 /CdS (3)/CdSe). The SEM images of Cu 2 S counter electrodes prepared by zinc–copper alloy indicated nanosheets with high porosity that is much suitable for injection of electrolyte while in two other approaches (SILAR and spray pyrolysis), large (∼50–70 nm) and small (∼10–17 nm) nanoparticles were observed without high porosity.
58 citations
References
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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.
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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.
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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...
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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.
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