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Journal ArticleDOI

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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Journal ArticleDOI
TL;DR: This work reviews the historical development of Transition metal dichalcogenides, methods for preparing atomically thin layers, their electronic and optical properties, and prospects for future advances in electronics and optoelectronics.
Abstract: Single-layer metal dichalcogenides are two-dimensional semiconductors that present strong potential for electronic and sensing applications complementary to that of graphene.

13,348 citations

Journal ArticleDOI
TL;DR: Dye-sensitized solar cells (DSCs) offer the possibilities to design solar cells with a large flexibility in shape, color, and transparency as mentioned in this paper, and many DSC research groups have been established around the world.
Abstract: Dye-sensitized solar cells (DSCs) offer the possibilities to design solar cells with a large flexibility in shape, color, and transparency. DSC research groups have been established around the worl ...

8,707 citations

Journal ArticleDOI
TL;DR: Nanocrystals (NCs) discussed in this Review are tiny crystals of metals, semiconductors, and magnetic material consisting of hundreds to a few thousand atoms each that are among the hottest research topics of the last decades.
Abstract: Nanocrystals (NCs) discussed in this Review are tiny crystals of metals, semiconductors, and magnetic material consisting of hundreds to a few thousand atoms each. Their size ranges from 2-3 to about 20 nm. What is special about this size regime that placed NCs among the hottest research topics of the last decades? The quantum mechanical coupling * To whom correspondence should be addressed. E-mail: dvtalapin@uchicago.edu. † The University of Chicago. ‡ Argonne National Lab. Chem. Rev. 2010, 110, 389–458 389

3,720 citations

Journal ArticleDOI
TL;DR: In this paper, the development of different strategies to modify TiO2 for the utilization of visible light, including non metal and/or metal doping, dye sensitization and coupling semiconductors are discussed.
Abstract: Fujishima and Honda (1972) demonstrated the potential of titanium dioxide (TiO2) semiconductor materials to split water into hydrogen and oxygen in a photo-electrochemical cell. Their work triggered the development of semiconductor photocatalysis for a wide range of environmental and energy applications. One of the most significant scientific and commercial advances to date has been the development of visible light active (VLA) TiO2 photocatalytic materials. In this review, a background on TiO2 structure, properties and electronic properties in photocatalysis is presented. The development of different strategies to modify TiO2 for the utilization of visible light, including non metal and/or metal doping, dye sensitization and coupling semiconductors are discussed. Emphasis is given to the origin of visible light absorption and the reactive oxygen species generated, deduced by physicochemical and photoelectrochemical methods. Various applications of VLA TiO2, in terms of environmental remediation and in particular water treatment, disinfection and air purification, are illustrated. Comprehensive studies on the photocatalytic degradation of contaminants of emerging concern, including endocrine disrupting compounds, pharmaceuticals, pesticides, cyanotoxins and volatile organic compounds, with VLA TiO2 are discussed and compared to conventional UV-activated TiO2 nanomaterials. Recent advances in bacterial disinfection using VLA TiO2 are also reviewed. Issues concerning test protocols for real visible light activity and photocatalytic efficiencies with different light sources have been highlighted.

3,305 citations

Journal ArticleDOI
TL;DR: In this paper, the authors discussed the steps that have led to this discovery, and the future of this rapidly advancing concept have been considered, and it is likely that the next few years of solar research will advance this technology to the very highest efficiencies while retaining the very lowest cost and embodied energy.
Abstract: Over the last 12 months, we have witnessed an unexpected breakthrough and rapid evolution in the field of emerging photovoltaics, with the realization of highly efficient solid-state hybrid solar cells based on organometal trihalide perovskite absorbers. In this Perspective, the steps that have led to this discovery are discussed, and the future of this rapidly advancing concept have been considered. It is likely that the next few years of solar research will advance this technology to the very highest efficiencies while retaining the very lowest cost and embodied energy. Provided that the stability of the perovskite-based technology can be proven, we will witness the emergence of a contender for ultimately low-cost solar power.

2,506 citations

References
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Journal ArticleDOI
12 Mar 2008-ACS Nano
TL;DR: It is demonstrated that when a positive potential is applied to the film in an acetonitrile electrolyte, the PL is irreversibly quenched, indicating that photobrightening and charge carrier injection are coupled processes.
Abstract: The photoluminescence (PL) of 2D monolayers of CdSe/CdS/ZnS semiconductor nanocrystals (NCs) deposited on gold substrates and incorporated into electrochemical cells has been studied. By combining simultaneous cyclic voltammetry and confocal microscopy it is demonstrated that when a positive potential is applied to the film in an acetonitrile electrolyte, the PL is irreversibly quenched. This is irrespective of whether the samples are under an inert atmosphere or exposed to air or water vapor. When a negative potential is applied under nitrogen, quenching is also observed; however, it is reversible. Conversely when a negative potential is applied to the NC films in aerated acetonitrile, the PL intensity increases. The enhancement of the PL is stable for at least 180 s while the potential is held at −1.0 V (vs Ag quasi-reference electrode). When the potential is removed the PL intensity returns to the starting value. These results clearly indicate that photobrightening and charge carrier injection are coup...

84 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used single-walled carbon nanotubes (SWCNTs) on indium-doped tin oxide (ITO) electrodes to increase the short-circuit current under the irradiation condition and also reduced the charge recombination process under the dark condition.
Abstract: This paper reports the modification of CdS∕TiO2 quantum-dot sensitized solar cells by using single-walled carbon nanotubes (SWCNTs) on indium-doped tin oxide (ITO) electrodes. The presence of the SWCNT layers on an ITO electrode increased the short-circuit current under the irradiation condition and also reduced the charge recombination process under the dark condition. The power conversion efficiency of CdS∕TiO2 on ITO increased 50.0% in the presence of SWCNTs due to the improved charge-collecting efficiency and reduced recombination.

81 citations

Journal ArticleDOI
TL;DR: In this article, a 3:1 cluster of fullerene−bridge−aniline dyad and the model fulleropyrrolidine compound was shown to exhibit a red-shifted emission maximum (λmax ∼ 738 nm) compared to their corresponding monomeric forms.
Abstract: Fullerene−bridge−aniline dyad and the model fulleropyrrolidine compound form stable, optically transparent clusters in mixtures (3:1) of acetonitrile and toluene. Ground- and excited-state properties of the clusters of the dyad and the model compound are compared with their corresponding monomeric forms. Clustering of the dyad as well as the model compound exhibits a red-shifted emission maximum (λmax ∼ 738 nm) compared to their monomeric forms (λmax ∼ 714 nm). The electron transfer from the appended electron donor moiety to the parent fullerene core in the dyad cluster is evident from the decreased (∼80%) fluorescence yield. The formation of fullerene radical anion (absorption maximum at 1010 nm) with a lifetime of several hundreds of microseconds was further confirmed using nanosecond laser (337 nm) flash photolysis experiments. In contrast, the dyad molecules in their monomeric form did not yield any detectable yield of C60 radical anion following laser pulse excitation. The failure to observe any char...

80 citations