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: In this article, a hierarchical structure comprising doubly open-ended TiO2 nanotube (NT) arrays with various layers of few-nanometer-sized nanoparticles (NPs) was proposed to investigate the electron collection mechanisms in homogeneous hybrid structures.
Abstract: We prepared well-defined hierarchical structures comprising doubly open-ended TiO2 nanotube (NT) arrays covered with various layers of few-nanometer-sized TiO2 nanoparticles (NPs) to investigate the electron collection mechanisms in homogeneous hybrid structures. We found that competitive electron transport pathways (direct transport through the NT and randomized transport through the NPs) are present in the homogeneous hybrid structures. Photoinduced electrons generated at the few-nanometer-sized TiO2 NPs directly connected with TiO2 NTs (e.g., isolated and single-layer NPs on the surface of NTs) dominantly traveled to the NTs. With an increasing number of TiO2 NP layers, photoinduced electrons are randomly transported through the TiO2 NP layers. Enhanced light harvesting and efficient charge collection (∼95%) caused by the increased amounts of dye loading and the direct transport through the NT, respectively, are achieved in a structure with ∼1.4 layers of few-nanometer-sized TiO2 NPs, resulting in a po...
32 citations
TL;DR: This study highlights the efficient wiring of flavin adenine dinucleotide-dependent glucose dehydrogenase to PbS quantum dot (QD)-sensitized inverse opal TiO2 electrodes (IO-TiO2) by means of an Os-complex-containing redox polymer for the light-driven glucose oxidation.
Abstract: The functional coupling of photoactive nanostructures with enzymes creates a strategy for the design of light-triggered biocatalysts. This study highlights the efficient wiring of flavin adenine dinucleotide (FAD)-dependent glucose dehydrogenase (FAD-GDH) to PbS quantum dot (QD)-sensitized inverse opal TiO2 electrodes (IO-TiO2) by means of an Os-complex-containing redox polymer for the light-driven glucose oxidation. For the construction of IO-TiO2 scaffolds, a template approach has been developed, enabling the tunability of the surface area and a high loading capacity for the integration of QDs, redox polymer, and enzyme. The biohybrid signal chain can be switched on with light, generating charge carriers within the QDs, triggering a multistep electron-transfer cascade from the enzyme toward the redox polymer via the QDs and finally to the IO-TiO2 electrode. The resulting anodic photocurrent can be modulated by the potential, the excitation intensity, and the glucose concentration, providing a new degree...
32 citations
TL;DR: In this article, a uniform set of mono-crystalline nanoparticles ranging from 6 nm to over 100 nm were prepared for the MgO, Co3O4, and Fe3O 4 oxide systems and characterized by transmission electron microscopy (TEM) and x-ray diffraction (XRD).
Abstract: Uniform sets of mono-crystalline nanoparticles ranging from 6 nm to over 100 nm were prepared for the MgO, Co3O4, and Fe3O4 oxide systems. The nanoparticles were characterized by transmission electron microscopy (TEM) and x-ray diffraction (XRD). A careful analysis shows increased lattice parameter for smaller nanoparticles of each oxide system: 0.47% expansion from bulk for 7 nm MgO crystallites, 0.15% expansion from bulk for 9 nm Co3O4 crystallites, and 0.13% expansion from bulk for 6 nm Fe3O4 crystallites. The compressive surface stresses and expansion energies against hydrostatic pressure for each oxide system were calculated, respectively, to be 4.13 N/m and 1.8 meV/formula unit for MgO, 3.09 N/m and 0.87 meV/formula unit for Co3O4, and 1.26 N/m and 0.67 meV/formula unit for Fe3O4. The fundamental understanding of oxide nanoparticle mechanics as presented here will facilitate integration of these materials into technological applications in a rationally designed manner.
32 citations
TL;DR: In this article, a unique concept of photoreference electrode developed for thin photoelectrochemical solar cells enables threeelectrode characterization of quantum dot sensitized solar cells (QDSSCs) under operat...
Abstract: A unique concept of photoreference electrode developed for thin photoelectrochemical solar cells enables three-electrode characterization of quantum dot sensitized solar cells (QDSSCs) under operat...
32 citations
TL;DR: The polarizability of the CdSe/P3HT interface is key to achieving efficient charge separation and slow back electron transfer, two of the most important processes to boost the photocurrent and voltage in C dSe/ P3HT photovoltaic devices.
Abstract: We report our results on the influence of the dipole moment of small molecules anchored to the surface of CdSe nanocrystals, over the interfacial charge recombination dynamics in CdSe/P3HT (P3HT : poly-3-hexylthiophene). The polarizability of the CdSe/P3HT interface is key to achieving efficient charge separation and slow back electron transfer, two of the most important processes to boost the photocurrent and voltage in CdSe/P3HT photovoltaic devices.
32 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