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: 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.
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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 ...
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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
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
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.
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References
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TL;DR: In this paper, the photoluminescence quenching of a CdSe quantum dot by hexanethiolate-monolayer-protected gold clusters (MPCs) with core diameters of 1.1−4.9 nm is described.
Abstract: The photoluminescence quenching of a CdSe quantum dot by hexanethiolate-monolayer-protected gold clusters (MPCs) with core diameters of 1.1−4.9 nm is described. Experimental evidence suggests that the quenching occurs via an energy transfer mechanism. The energy transfer quenching efficiencies of MPCs were compared using Stern−Volmer plots. The quenching constant (KQ) obtained from the slope of the plot shows an enormous increase from 2.5 × 105 to 2.3 × 108 M-1 by nearly 1000-fold as the core size increases from 1.1 to 4.9 nm. The origin of the size dependence is considered. There is a remarkable linear correlation found between the quenching constant and the MPC core volume. This correlation suggests that the energy transfer quenching efficiency is governed by the absorption cross-section of the MPC quencher that scales as its core volume.
41 citations
TL;DR: In this paper, the authors classified composite semiconductor nanoclusters into two categories, capped and coupled type heterostructures, and discussed the photo-induced charge transfer processes in single and multicomponent semiconductor nano-structures.
Abstract: Publisher Summary This chapter discusses some important features of chemically synthesized semiconductor heterostructures. By controlling the methods of preparation it is possible to tailor the photocatalytic property of these composite semiconductor nanoclusters. Their ability to carry out redox processes, with greater efficiency and selectivity than the single component systems has made them potential candidates for the conversion and storage of solar energy, and in the mineralization of chemical pollutants. These systems have potential applications in designing novel microheterogeneous assemblies, microelectronics, and chemical sensors. The feasibility of synthesizing composite semiconductor nanoclusters, by chemical precipitation or electrochemical deposition, opens up a wide array of possibilities, in utilizing these materials for chemical sensors, electrooptics, microelectronics, imaging technology, and photovoltaics. The chapter classifies composite semiconductor nanoclusters into two categories— namely, capped and coupled type heterostructures. The capped nanoclusters essentially have a coreshell geometry, while in a coupled system two semiconductor nanoclusters are in contact with each other. Photo-induced charge transfer processes in single and multicomponent semiconductor nanostructures are discussed in the chapter.
40 citations
TL;DR: Results show that the degree of P3HT chain ordering is strongly affected by RR, and that thermal annealing improves chain ordering in the OOP direction, in good agreement with high resolution transmission electron microscope measurements of film nanomorphology.
Abstract: Here we report a study of the polymer chain/nanocrystal ordering in thin films (nanolayers) of regioregular poly(3-hexylthiophene) (P3HT) and blends of P3HT with a soluble fullerene derivative. A detailed analysis has been made of two dimensional (2D) grazing incidence X-ray diffraction (GIXRD) measurements with synchrotron radiation. P3HT samples with three different levels of regioregularity (RR) were synthesized and used to investigate the influence of RR on the chain ordering in thin films. Blend films were also prepared to investigate the influence of fullerene molecule addition on chain ordering. For the analysis, one dimensional (1D) GIXRD patterns were extracted from the 2D images for varying azimuthal angles, allowing information to be obtained for chain ordering in both the out-of-plane (OOP) and in-plane (IP) directions. These results show that the degree of P3HT chain ordering is strongly affected by RR, and that thermal annealing improves chain ordering in the OOP direction. This observation is in good agreement with high resolution transmission electron microscope measurements of film nanomorphology.
39 citations
TL;DR: In this paper, transient absorption saturation measurements on lead sulfide colloidal nanocrystals at the first and second exciton energies were reported and fit the results to a model incorporating intraband and interband relaxation processes.
Abstract: We report transient absorption saturation measurements on lead sulfide colloidal nanocrystals at the first and second exciton energies and fit the results to a model incorporating intraband and interband relaxation processes We study in detail the Auger recombination from the first excited state, which takes place when more than one electron-hole pair is excited in a dot We find an Auger coefficient of 45 x 10 -30 cm 6 /s for dots of 55 nm diameter, and observe saturation of the absorption bleaching when the (8-fold degenerate) first level is filled We develop a model for the absorption dynamics using Poisson statistics and find a good fit with our experimental measurements
39 citations
TL;DR: In this paper, small CdSe colloids that exhibit quantization effects are prepared in acetonitrile and they show intensive transient photobleaching in the 370-500-nm region and transient absorption around 300 and 500-600 nm immediately after bandgap excitation of the semiconductor.
Abstract: Small CdSe colloids (particle diameter 30-50 A) that exhibit quantization effects are prepared in acetonitrile. The authors show intensive transient photobleaching in the 370-500-nm region and transient absorption around 300 and 500-600 nm immediately after bandgap excitation of the semiconductor. The nature and kinetic behavior of the transient photobleaching, which is attributed to the trapped charge carriers, are elucidated by investigating the influence of laser dose and various hole and electron scavengers.
38 citations