Generalized syntheses of large-pore mesoporous metal oxides with semicrystalline frameworks

Yang, Peidong; Zhao, Dongyuan; Margolese, D.; Chmelka, Bradley F.; Stucky, Galen D.

doi:10.1038/24132

Cited by 2,458 publications

(1,953 citation statements)

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“…21,22 The general idea of this bottom-up approach is the following: a nanoparticle (1-4 nm) sol of the desired oxide (SiO 2 , TiO 2 , Nb 2 O 5 , etc.) is mixed with a block copolymer, consisting of two or more incompatible building blocks.…”

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Dye-Sensitized Solar Cell Based on a Three-Dimensional Photonic Crystal

et al. 2010

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We present a material assembly route for the manufacture of dye-sensitized solar cells, coupling a high-surface mesoporous layer to a three-dimensional photonic crystal (PC). Material synthesis aided by self-assembly on two length scales provided electrical and pore connectivity at the mesoporous and the microporous level. This construct allows effective dye sensitization, electrolyte infiltration, and charge collection from both the mesoporous and the PC layers, opening up additional parameter space for effective light management by harvesting PC-induced resonances.KEYWORDS Photonic crystal, self-assembly, photovoltaics, dye-sensitized solar cell E ver since the pioneering work of O'Regan and Grät-zel, dye-sensitized solar cells (DSCs) have attracted great interest as a promising technology for future sustainable energy generation. 1 In DSCs, charge carrier generation takes place in a chemisorbed monolayer of photoactive dye which is sandwiched between a semiconductor oxide, usually mesoscopic anatase, and an electrolyte acting as electron and hole conducting materials, respectively. Using state-of-the-art ruthenium-based inorganic dyes, efficiencies higher than 11% have been reported. [2][3][4] DSCs are generally made from cheap and nontoxic components and can be designed in a variety of different colors and transparencies, which distinguishes them as an ideal photovoltaic concept for integrated architecture. It therefore seems only a matter of time before large scale production will follow. 5 In general, improvements in the overall power conversion efficiency have been centered on increasing the photovoltage through manipulation of the oxide, improving the photocurrent with new dyes, and increasing stability by better encapsulation. 5 While record-holding liquid electrolyte DSCs already achieve maximum quantum efficiency (photon-toelectron conversion) in the spectral range around 520 nm, light harvesting in the red and near-infrared (at the tail of the absorption spectra) is still relatively low. In solid-state devices, light absorption is generally limited by the film thickness, as thick mesoporous films prove difficult to infiltrate. 6 One way to successfully enhance light harvesting is the introduction of optical elements, such as highly scattering layers. These consist of large particles, that increase the photon path length in the cell. 7,8 This ubiquitous approach has the unfortunate effect of rendering the DSC opaque thus depriving it of one of its main advantages over competing technologies. As a result, photonic band gap materials in the form of 3D inverted TiO 2 opal or porous bragg stacks have been applied to DSCs to enhance light harvesting in specific partsofthespectrumwhileretainingthecelltransparency. 9-12 Several theoretical approaches report a variety of possible effects, including the localization of heavy photons near the edges of a photonic bandgap, 13 Bragg diffraction in a periodic lattice, 14 multiple scattering at disordered regions in the photonic crystal (PC), 15 and the for...

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Dye-Sensitized Solar Cell Based on a Three-Dimensional Photonic Crystal

et al. 2010

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“…Meso-and macroporous solids are usually made in the presence of organic templates which then have to be removed without damaging the inorganic shell 7,8 . In the foaming method we describe here, amines are simply intercalated between vanadium oxide planes and do not act as templates for the formation of macropores.…”

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Macroporous crystalline vanadium oxide foam

Chandrappa

Steunou

Livage

2002

Nature

153

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“…However, unlike the silicate or aluminate precursors, most inorganic precursors can not hydrolyze or hydrolyze in a quite high speed. 3D interlinked frameworks of these components are difficult to be generated with stable long-range periodic structures (50,51).…”

Section: Surfactant Self-assembly Approachmentioning

confidence: 99%

“…To synthesize nonsiliceous ordered mesoporous materials, the important success appeared when the versatile evaporation induced self-assembly (EISA) strategy under the non-aqueous system was introduced to synthesize mesoporous metal oxides (50,53). It was initially used in the preparation of mesoporous silica thin films by Brinker and coworkers (52).…”

Section: Surfactant Self-assembly Approachmentioning

confidence: 99%

“…The inorganic species are further polymerized and condensed, gradually forming the mesostructures (Figure 3) (54)(55)(56). Semicrystalline frameworks were obtained where nanocrystallites nucleated within the amorphous inorganic matrices (50). However, the compositions of ordered mesoporous oxides directly obtained from the EISA approach are still limited.…”

Section: Surfactant Self-assembly Approachmentioning

confidence: 99%

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General Synthesis of Ordered Nonsiliceous Mesoporous Materials

Wan

Yang

Zhao

2008

ACS Symposium Series

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The design of ordered nonsiliceous mesoporous materials is illustrated based on the surfactant assembly and confinedspace growth. These materials include mesoporous metal oxides, polymers, and carbons with open framework structures, and single-crystal metal, metal oxide and carbon nanoarrays with replicated mesostructures. A generalized "acid-base pair" concept, which self-adjusts the acidity and homogeneity of the inorganic precursor, is proposed to prepare highly ordered mesoporous metal oxides, phosphates and borates, as well as mixed metal oxides and phosphates, with diverse structures. Mesoscopically ordered polymer frameworks with uniformly large pore sizes are derived from the self-assembly from organic templates and organic precursors. Heating these materials transforms them to homologous carbon frameworks. Microwave digested method is an efficient way to enhance the adsorption property of hard silica templates in fabricating ordered nonsiliceous single-crystal nanoarrays. The coordination of organic surfactants with metal ions is also a method to increase the interaction between hard templates and precursors. A one-step impregnation process is used to fabricate ordered silica monoliths with various metal oxide nanocrystals. Improving the interactions between the precursors themselves plays an essential role in replicating ordered mesoporous CdS, SiC and graphitized carbons. Preliminary applications in bone-forming materials, biosensors and electrodes are presented as well.

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Generalized syntheses of large-pore mesoporous metal oxides with semicrystalline frameworks

Cited by 2,458 publications

References 23 publications

Dye-Sensitized Solar Cell Based on a Three-Dimensional Photonic Crystal

Dye-Sensitized Solar Cell Based on a Three-Dimensional Photonic Crystal

Macroporous crystalline vanadium oxide foam

General Synthesis of Ordered Nonsiliceous Mesoporous Materials

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