Multimolecular assemblies on high surface area metal oxides and their role in interfacial energy and electron transfer

Abstract

High surface area metal oxides offer a unique substrate for the assembly of multiple molecular components at an interface. The choice of molecules, metal oxide, and the nature of the assembly method can have a profound influence on the mechanism, rate, and efficiency of photoinduced energy and electron transfer events at the interface. Owing to their diversity and high level of control, these interfacial assemblies are of interest for numerous applications including solar energy conversion, photoelectrosynthesis, photo-writable memory, and more. Although these assemblies are generated with very different goals in mind, they rely on similar surface binding motifs and molecular structure-property relationships. Therefore, the goal of this review is to summarize the various strategies (i.e. co-deposition, axial coordination, metal ion linkages, electrostatics, host-guest interactions, etc.) for assembling chromophores, hosts, electron donors/acceptors, and insulating co-adsorbent molecules on mesoporous metal oxide substrates. The assembly, synthesis, and characterization, as well as subsequent photoinduced events (i.e. cross-surface energy/electron transfer, interchromophore energy transfer, electron injection, and others) are discussed for the various assembly strategies.

Immobilization of Molecular Catalysts for Enhanced Redox Catalysis

“…High performance dye‐sensitized solar cells (DSSCs) have so far been mainly fabricated by use of ruthenium polypyridine complexes and zinc porphyrins as the light‐harvesting and charge‐separation components, respectively, affording the highest power conversion efficiency (PCE=13.0 %) under photoirradiation of simulated sunlight (1 Sun=AM 1.5G) at 100 mW cm −2 . Metal‐free organic electron donor‐acceptor linked compounds have recently emerged as the near‐infrared photosensitizing dyes, exhibiting over 80 % external quantum efficiency (EQE) in a broad spectral range, and a high power conversion efficiency (PCE=13.0 %) under photoirradiation of simulated sunlight (AM 1.5G) at 100 mW cm −2 …”

“…High performanced ye-sensitized solar cells (DSSCs) have so far been mainly fabricated by use of ruthenium polypyridinec omplexesa nd zinc porphyrins as the light-harvesting and chargeseparation components,r espectively,a ffording the highest powerc onversion efficiency (PCE = 13.0 %) under photoirradiation of simulated sunlight (1 Sun = AM 1.5G) at 100 mW cm À2 . [82][83][84][85] Metal-free organic electron donor-acceptor linked compounds have recently emerged as the near-infrared photosensitizing dyes, exhibiting over 80 %e xternalq uantum efficiency (EQE) in ab road spectral range, and ah igh power conversion efficiency (PCE = 13.0 %) under photoirradiation of simulated sunlight (AM 1.5G) at 100 mW cm À2 . [86][87][88] Ah igherP CE of 14.3 %w ith the maximum incident photonto-current conversion efficiency (IPCE) of 91 %h as been attained by use of ap hotosensitizer,i .e.,c arbazole/alkyl-functionalized oligothiophene/alkoxysilyl-anchor dye( ADEKA-1 in Figure9a), [89] as together with the co-sensitizer (LEG415 in Figure 9b), [90] and [Co(phen) 3 ] 3 + /2 + (phen:1 ,10-phenanthroline) as the redox electrolyte couple under photoirradiation of simulated sunlight (AM 1.5G) at a1 00 mW cm À2 intensity ( Figure 10).…”

Multidentate Anchors for Surface Functionalization

“…The advantages of SAMs include easy operation, spontaneous formation of ordered films in situ, high surface coverage with few defects, and good thermodynamic stability. The LBL fabrications with SAMs as the template layer could be used to pursue higher and more advanced functionalities …”

“…The LBL fabricationsw ith SAMs as the template layer could be used to pursue higher and more advanced functionalities. [24][25][26][27][28][29][30] During the fabrication of functional SAMs,t he control over the interaction of anchoring groups with particular substrates is critical. Common substrates include noble metals( gold, silver,p latinum, and copper,e tc.…”

An Efficient Aniline‐Based Co‐Sensitizer for High Performance N3‐Sensitized Solar Cells

“…One of the classic examples was the co‐sensitization of DSSCs sensitized with a black dye using metal‐free organic dye (Y1 or D131) which resulted in enhanced photocurrent density and hence improved PCE up to 11.0‐11.4% . Till date, the optimum photon conversion efficiency (PCE) of 14.3% has been achieved for the such DSSCs under ambient atmosphere ,. Encouraged by these results, several research groups, including ours, have demonstrated various organic push‐pull configured dyes derived from electron rich donors such as triphenylamine, indole, carbazole, phenothiazine, thiophene, etc.…”