TEKNIK ELEKTRONIKA

Nature's photosynthesis process far outperforms man-made light-energy-converting devices. The highly efficient mechanism for rapid separation and transfer of photo-excited charge pairs in the photosynthetic reaction center is a key step. In many thin-film solar-cell efforts, this charge separation is a critical challenge. In response, several fundamental studies have modeled nature's multistep charge-transfer process, which aids in precluding charge-pair recombination, or directly incorporated photosynthetic complexes into devices.

 

Electrochemical solar-cell performance can also suffer from high light conditions or repeated exposures, damaging the donor dye molecules. Nature addresses this irreversible photodegradation elegantly by removing and replacing photodamaged components as often as once every hour. A group of researchers at Purdue University has been working on development of photovoltaic nanostructures with synthetic analogs to nature's efficient charge-separation and regeneration processes, forming the basis for a new class of electrochemical solar cells.

 

Because of the combination of a high electron-accepting tendency and unmatched electrical-conductivity properties, carbon nanotubes have been subject of much attention in donor/acceptor nanohybrid studies. These aim to develop optimized hybrids of molecular donors and acceptors, the foundation for electrochemical solar-cell devices.

 

As opposed to relying on either covalent or noncovalent interactions with donors such as porphyrins, ruthenium-based complexes, or semiconductor nanocrystals, Purdue University researchers have developed new strategies using highly functional biomolecules for direct noncovalent aqueous solubilization and functionalization of carbon nanotubes, preserving their electronic structure and unique properties. These biomolecules bind the donors with acceptors, and facilitate charge transport and regeneration.

 

By varying the size of the biomolecule, it is possible to control the intermolecular distance between donor and acceptor, a critical aspect in charge-separation and recombination kinetics. Additionally, by changing the local environment, the structure of the biomolecule can be altered, modifying the binding conditions with the donor and allowing for removal and replacement with fresh donor molecules for optimal photoconversion.

 

Source: SPIE Newsroom

More info

http://www.spie.org



View the Original article