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 paper, a graphite powder (GP) film-supported counter electrode (CE) has been prepared by an accessible and low-temperature method, where GP films provide large areas for the loading of the flake-like catalytic active Cu2S particles.
Abstract: A graphite powder (GP) film-supported Cu2S counter electrode (CE) has been prepared by an accessible and low-temperature method. GP film is prepared using a doctor-blading technique on an F-doped SnO2 conducting glass (FTO) substrate, while Cu2S is formed by immersion and heat treatment of a metal chalcogenide complex (N4H9Cu7S4) in an air atmosphere. GP films provide large areas for the loading of the flake-like catalytic active Cu2S particles. The lamellar structures of GP also provide an excellent electrical pathway for faster charge transportation from the external circuit to the catalyst, Cu2S. Electrochemical impedance spectroscopy and Tafel characterizations indicate that the GP film-supported Cu2S CE constructed using three Cu2S deposition cycles (GP-3Cu2S) exhibits a much smaller charge transfer resistance (Rct) and higher catalytic activity than Pt or bare Cu2S. The quantum dot-sensitized solar cells (QDSSCs) with GP-3Cu2S CEs have a photovoltaic conversion efficiency (PCE) of 4.59%. Moreover, the cells with GP-xCu2S CE exhibit excellent stability under conventional working conditions for 12 h without any obvious decay in the PCE. In contrast, the PCE degrades severely for cells based on Pt or bare Cu2S.
28 citations
TL;DR: In this paper, a core-hole clock implementation of resonant photoemission spectroscopy (RPES) was used to investigate the charge transfer dynamics across the interface of 3,4,9,10-perylenetetetricarboxylic dianhydride (PTCDA) organic molecules and the reduced rutile TiO2 (110) 1 × 1 surface.
Abstract: Charge transfer dynamics across the interface of 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) organic molecules and the reduced rutile TiO2 (110) 1 × 1 surface has been investigated using core-hole clock implementation of resonant photoemission spectroscopy (RPES). It is found that ultrafast charge transfer from PTCDA molecules to TiO2 substrate takes place on the time scale of 8–20 fs due to their strong electronic coupling. Moreover, the charge transfer time scale at the PTCDA/TiO2 (110) interface shows evident orientational dependence which varies with the molecular site owing to different electronic coupling strengths.
28 citations
TL;DR: A new method for in situ reversible tuning of photoluminescence properties of quantum dots (Qdots) by partial oxidation of population of the emitting species and subsequent chemical reduction of the oxidized form is reported.
Abstract: Herein we report the development of a new method for in situ reversible tuning of photoluminescence properties of quantum dots (Qdots) by partial oxidation of population of the emitting species and subsequent chemical reduction of the oxidized form. The concept has been demonstrated using Mn2+-doped ZnS Qdots stabilized by acetyl acetonate. Treatment of an aqueous solution of the Qdots (with Mn(OAc)2 being the source of Mn used for the synthesis of the Qdots) by potassium peroxodisulfate (KPS) led to reduction of intensity of emission due to Mn2+ (4T1-6A1). Subsequent treatment of the solution containing KPS-treated Qdots with NaBH4 led to regaining of intensity, thus providing reversibility to the tuning, which was possible for more than one cycle. Electron spin resonance (ESR) spectroscopic investigations revealed reduction of the population of Mn2+ upon treatment with KPS, whereas it went back up upon further treatment with NaBH4. Interestingly, a mixed population of oxidation states of Mn was indicate...
28 citations
TL;DR: In this article, the authors systematically review the recent progress on metal chalcogenide-based QDSCs in practical applications from three main functional points, namely, QD sensitizers, counter electrodes (CEs), and interface modification layers.
Abstract: As one of the most promising third-generation photovoltaics devices, quantum dot-sensitized solar cells (QDSCs) have attracted increasing attention due to their easy fabrication, low cost, potential high efficiency, etc. Thus, substantial efforts have been taken to boost their photoelectrical conversion efficiencies (PCEs) and device stability consistently by precisely optimizing the structure of materials and device architecture. Throughout the development of QDSCs, it is noteworthy to mention that metal chalcogenide-based semiconductors have been key materials in capturing sunlight as sensitizers, catalytic electrolyte reduction as counter electrodes (CEs), and interface charge transport as interface modification layers. Herein, we systematically review the recent progress on metal chalcogenide-based QDSCs in practical applications from three main functional points, specifically, QD sensitizers, counter electrodes (CEs), and interface modification layers. Besides, we have outlined the fundamental structure, operation principle, and brief history of these sensitized solar cells. Finally, the state of existing challenges and future prospects for QDSCs employing various metal chalcogenides are also discussed.
28 citations
TL;DR: In this paper, a simple, green, and room temperature synthetic route for the formation of Si quantum dots (Si QDs) and Au nanoparticle-Si quantum dot (Au NP-Si QD) nanocomposites was reported.
Abstract: We report a simple, green, and room temperature synthetic route for the formation of Si quantum dots (Si QDs) and Au nanoparticle–Si quantum dot (Au NP-Si QD) nanocomposites. Glucose was used as a ...
28 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