Enhanced light-harvesting in quantum dot-metal-organic frameworks

Feb 26, 2013
Enhanced light-harvesting in quantum dot: Metal-organic frameworks
A schematic of directional energy (exciton) migration in the MOF, along with the porphyrin building-blocks of the MOF, is shown.

Center for Nanoscale Materials (CNM) users from Northwestern University, working together with the Nanophotonics Group at the Argonne National Laboratory, report the functionalization of porphyrin-based metal-organic frameworks (MOFs) with CdSe/ZnS core/shell quantum dots (QDs) for the enhancement of light harvesting via energy transfer from the QDs to the MOFs. This work paves the road for the development of efficient light harvesting complexes for solar energy conversion.

Because of their efficient energy-transport properties, porphyrin-based MOFs are attractive compounds for solar photochemistry applications. However, their absorption bands provide limited coverage in the visible spectral range for light-harvesting applications. The broad of the QDs in the visible region offers greater coverage of the by QD-MOF hybrid structures. Time-resolved emission studies at CNM show that photoexcitation of the QDs is followed by energy transfer to the MOFs with efficiencies of more than 80%.

Enhanced light-harvesting in quantum dot: Metal-organic frameworks
Schematic of QD sensitization and energy transfer to the MOFs; QDs are 5-6 nm and the interporphyrin spacing is about 1 nm.

This sensitization approach can result in a >50% increase in the number of photons harvested by a single monolayer MOF structure with a monolayer of QDs on the MOF surface. Porphyrin molecules with different substituents were used to alter the degree of structural anisotropy in the MOF, in order to preferentially increase the anisotropy in electronic coupling between porphyrins in specific directions, so as to produce anisotropic energy migration. Theoretical evaluation of the coupling constants also was performed.

Explore further: World's smallest propeller could be used for microscopic medicine

More information: S. Jin et al., Energy Transfer from Quantum Dots to Metal-Organic Frameworks for Enhanced Light Harvesting, J. Am. Chem. Soc. 135, 955 (2013).

H.-J. Son et al., Light Harvesting and Ultrafast Energy Migration in Porphyrin-Based Metal-Organic Frameworks, J. Am. Chem. Soc. 135, 862 (2013).

add to favorites email to friend print save as pdf

Related Stories

MOFs materials special review issue

Feb 22, 2012

New analyses of more than 4,000 scientific studies have concluded that a family of "miracle materials" called MOFs have a bright future in products and technologies — ranging from the fuel tanks in hydrogen-powered cars ...

'Seeding' the next generation of smart materials

Mar 18, 2011

(PhysOrg.com) -- Scientists at CSIRO have developed a simple but effective technique for growing and adding value to an exciting new group of smart materials which could be used in areas such as optical sensing ...

Recommended for you

A new way to make microstructured surfaces

19 hours ago

A team of researchers has created a new way of manufacturing microstructured surfaces that have novel three-dimensional textures. These surfaces, made by self-assembly of carbon nanotubes, could exhibit a ...

Tough foam from tiny sheets

Jul 29, 2014

Tough, ultralight foam of atom-thick sheets can be made to any size and shape through a chemical process invented at Rice University.

User comments : 0