Topic
Heterojunction
About: Heterojunction is a research topic. Over the lifetime, 41859 publications have been published within this topic receiving 1000343 citations. The topic is also known as: Heterojunction.
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TL;DR: In this paper, the fabrication, properties, and solar energy applications of highly ordered TiO 2 nanotube arrays made by anodic oxidation of titanium in fluoride-based electrolytes are reviewed.
1,905 citations
TL;DR: Li et al. as mentioned in this paper provided an overview of the concept of heterojunction construction and more importantly, the current state-of-the-art for the efficient, visible-light driven junction water splitting photo(electro)catalysts reported over the past ten years.
Abstract: Solar driven catalysis on semiconductors to produce clean chemical fuels, such as hydrogen, is widely considered as a promising route to mitigate environmental issues caused by the combustion of fossil fuels and to meet increasing worldwide demands for energy. The major limiting factors affecting the efficiency of solar fuel synthesis include; (i) light absorption, (ii) charge separation and transport and (iii) surface chemical reaction; therefore substantial efforts have been put into solving these problems. In particular, the loading of co-catalysts or secondary semiconductors that can act as either electron or hole acceptors for improved charge separation is a promising strategy, leading to the adaptation of a junction architecture. Research related to semiconductor junction photocatalysts has developed very rapidly and there are a few comprehensive reviews in which the strategy is discussed (A. Kudo and Y. Miseki, Chemical Society Reviews, 2009, 38, 253–278, K. Li, D. Martin, and J. Tang, Chinese Journal of Catalysis, 2011, 32, 879–890, R. Marschall, Advanced Functional Materials, 2014, 24, 2421–2440). This critical review seeks to give an overview of the concept of heterojunction construction and more importantly, the current state-of-the art for the efficient, visible-light driven junction water splitting photo(electro)catalysts reported over the past ten years. For water splitting, these include BiVO4, Fe2O3, Cu2O and C3N4, which have attracted increasing attention. Experimental observations of the proposed charge transfer mechanism across the semiconductor/semiconductor/metal junctions and the resultant activity enhancement are discussed. In parallel, recent successes in the theoretical modelling of semiconductor electronic structures at interfaces and how these explain the functionality of the junction structures is highlighted.
1,891 citations
TL;DR: In this paper, a planar heterojunction CH3NH3PbI3-xCl x solar cells with thin solid films of a perovskite absorber was shown to achieve power conversion efficiencies of up to 11.4% with optimized solution-based film formation.
Abstract: Organometal trihalide perovskite based solar cells have exhibited the highest efficiencies to-date when incorporated into mesostructured composites. However, thin solid films of a perovskite absorber should be capable of operating at the highest efficiency in a simple planar heterojunction configuration. Here, it is shown that film morphology is a critical issue in planar heterojunction CH3NH3PbI3-xCl x solar cells. The morphology is carefully controlled by varying processing conditions, and it is demonstrated that the highest photocurrents are attainable only with the highest perovskite surface coverages. With optimized solution based film formation, power conversion efficiencies of up to 11.4% are achieved, the first report of efficiencies above 10% in fully thin-film solution processed perovskite solar cells with no mesoporous layer. © 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim.
1,856 citations
TL;DR: Luminescent measurements show that the efficiency increases with decreasing size of the particles, as expected within the framework of an electron-hole localization theory, suggesting that doped nanocrystals are indeed a new class of materials heretofore unknown.
Abstract: We report for the first time that doped nanocrystals of semiconductor can yield both high luminescent efficiencies and lifetime shortening at the same time. Nanocrystals of Mn-doped ZnS with sizes varying from 3.5 to 7.5 nm were prepared by a room temperature chemical process. These nanosized particles have an external photoluminescent quantum efficiency as high as 18% at room temperature and a luminescent decay at least 5 orders of magnitude faster than the corresponding ${\mathrm{Mn}}^{2+}$ radiative transition in the bulk crystals. Luminescent measurements show that the efficiency increases with decreasing size of the particles, as expected within the framework of an electron-hole localization theory. These results suggest that doped nanocrystals are indeed a new class of materials heretofore unknown.
1,855 citations
IBM1
TL;DR: In this paper, a theoretical model is presented to predict the band offsets at both lattice-matched and pseudomorphic strained-layer interfaces, based on the local density functional pseudopotential formalism and the ''model solid approach'' of Van de Walle and Martin.
Abstract: Semiconductor heterojunctions and superlattices have recently shown tremendous potential for device applications because of their flexibility for tailoring the electronic band structure. A theoretical model is presented to predict the band offsets at both lattice-matched and pseudomorphic strained-layer interfaces. The theory is based on the local-density-functional pseudopotential formalism and the ``model-solid approach'' of Van de Walle and Martin. This paper is intended as a self-contained description of the model, suitable for practical application. The results can be most simply expressed in terms of an ``absolute'' energy level for each semiconductor and deformation potentials that describe the effects of strain on the electronic bands. The model predicts reliable values for the experimentally observed lineups in a wide variety of test cases and can be used to explore which combinations of materials and configurations of the strains will lead to the desired electronic properties.
1,807 citations