. 24/7 Space News .
CHIP TECH
Molecular-like photochemistry from semiconductor nanocrystals
by Staff Writers
Raleigh NC (SPX) Jan 22, 2016


Illustration depicting semiconductor nanocrystal to molecule triplet energy transfer and established subsequent reactions. Image courtesy Dr. Cedric Mongin. For a larger version of this image please go here.

Researchers from North Carolina State University have demonstrated the transfer of triplet exciton energy from semiconductor nanocrystals to surface-bound molecular acceptors, extending the lifetime of the originally prepared excited state by six orders of magnitude. This finding has implications for fields ranging from solar energy conversion to photochemical synthesis to optoelectronics to light therapy for cancer treatment.

Excitons are the electron/hole pairs formed in semiconductor nanocrystals upon absorption of light, temporarily storing it as chemical energy. In solar cells, for example, the excitons transport energy through the material so that it can be collected and converted into electricity.

In terms of photochemistry, the major drawback to using most semiconductor nanocrystals as photosensitizers lies in their short excited state lifetimes - typically tens of nanoseconds - which renders them inadequate to drive photochemical reactions.

NC State chemistry professor Felix Castellano, along with postdoc Cedric Mongin and graduate student Sofia Garakyaraghi, wondered if it would be possible to extend the semiconductor nanocrystal excited state lifetime to time scales long enough to perform chemistry.

"The fundamental question was, 'Can we take a nanoparticle excited state with a lifetime of tens of nanoseconds and extend it through sensitization,'" says Castellano.

"If we take the original nanocrystal excited state and transfer its energy to a triplet acceptor on the surface of the nanomaterial, then the molecular triplet excited state you create should have a long enough lifetime to promote chemical reactions. This would also suggest that semiconductor nanocrystals exhibit molecular-like behavior."

Castellano's team used cadmium selenide (CdSe) nanocrystals capped with oleic acid, prepared by Prof. Mikhail Zamkov and his graduate student Natalia Razgoniaeva at Bowling Green State University. Some of the oleic acid is then replaced by the molecular triplet acceptor 9-anthacenecarboxylic acid (ACA).

When the CdSe nanocrystal bearing ACA is struck with a green laser pulse, the exciton produced in the CdSe is transferred to the ACA, forming a molecular triplet exciton with a millisecond lifetime. This represents a lifetime extension of six orders of magnitude, enabling subsequent chemical reactivity.

"The other benefit is that by translating the exciton away from the nanoparticle surface, instead of involving the nanoparticle itself in the desired chemical reactions, you won't degrade the nanoparticle," says Castellano. "It can keep absorbing light and transferring the energy into the bulk solution."


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only


.


Related Links
North Carolina State University
Computer Chip Architecture, Technology and Manufacture
Nano Technology News From SpaceMart.com






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Previous Report
CHIP TECH
Dutch hi-tech group ASML posts 'record' year in 2015
The Hague (AFP) Jan 20, 2016
Leading Dutch manufacturer of computer chip making systems ASML Wednesday declared 2015 a "record" year for sales which rose to 6.3 billion euros ($6.9 billion), with net profits leaping by 15 percent. The company, seen as a global hi-tech bellwether for the microprocessing industry, said profits had reached 1.39 billion euros, compared with 1.2 billion in 2014. "Our full-year 2015 net ... read more


CHIP TECH
Russia postpones manned Lunar mission to 2035

Audi joins Google Lunar XPrize competition

Lunar mission moves a step closer

Momentum builds for creation of 'moon villages'

CHIP TECH
Opportunity rock abrasion tool conducts two rock grinds

Opportunity Abrasion Tool Conducts Two Rock Grinds

Curiosity gets a good taste of scooped, sieved sand

Rover uses Rock Abrasion Tool to grind rocks

CHIP TECH
Voyager Mission Celebrates 30 Years Since Uranus

Engineers Mark Completion of Orion's Pressure Vessel

2016 Goals Vital to Commercial Crew Success

Space: The here-and-now frontier

CHIP TECH
China aims for the Moon with new rockets

China shoots for first landing on far side of the moon

Chinese Long March 3B to launch Belintersat-1 telco sat for Belarus

China Plans More Than 20 Space Launches in 2016

CHIP TECH
Astronaut Scott Kelly plays ping pong with water

Japanese astronaut learned Russian to link two nations

NASA, Texas Instruments Launch mISSion imaginaTIon

Water in US astronaut's helmet cuts short Briton's 1st spacewalk

CHIP TECH
Roscosmos Approves Delay of Eutelsat 9B Launch Due to Bad Weather

Assembly begins on 2nd Ariane 5 launcher for 2016

Ariane 5 is readied for an Arianespace leading customer Intelsat

EpicNG satellite installed on Ariane 5 for launch

CHIP TECH
Follow A Live Planet Hunt

Lab discovery gives glimpse of conditions found on other planets

Nearby star hosts closest alien planet in the 'habitable zone'

ALMA reveals planetary construction sites

CHIP TECH
New insights into the supercritical state of water

It's a 3-D printer, but not as we know it

Microsoft donates cloud computing 'worth $1 bn'

Research reveals mechanism for direct synthesis of hydrogen peroxide









The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.