Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > New technique could improve optical devices

 The orientation of light emission	The angular distribution of light emission from monolayer MoS2, left, closely matches the theoretical calculations for in-plane oriented emitters, right, indicating that light emission from MoS2 originates from in-plane oriented emitters.	Credit: Zia lab/Brown University
The orientation of light emission The angular distribution of light emission from monolayer MoS2, left, closely matches the theoretical calculations for in-plane oriented emitters, right, indicating that light emission from MoS2 originates from in-plane oriented emitters.

Credit: Zia lab/Brown University

Abstract:
Understanding the source and orientation of light in light-emitting thin films — now possible with energy-momentum spectroscopy — could lead to better LEDs, solar cells, and other devices that use layered nanomaterials.

New technique could improve optical devices

Providence, RI | Posted on March 5th, 2013

A multi-university research team has used a new spectroscopic method to gain a key insight into how light is emitted from layered nanomaterials and other thin films.

The technique, called energy-momentum spectroscopy, enables researchers to look at the light emerging from a thin film and determine whether it is coming from emitters oriented along the plane of the film or from emitters oriented perpendicular to the film. Knowing the orientations of emitters could help engineers make better use of thin-film materials in optical devices like LEDs or solar cells.

The research, published online on March 3 in Nature Nanotechnology, was a collaborative effort of Brown University, Case Western Reserve University, Columbia University, and the University of California-Santa Barbara.

The new technique takes advantage of a fundamental property of thin films: interference. Interference effects can be seen in the rainbow colors visible on the surface of soap bubbles or oil slicks. Scientists can analyze how light constructively and destructively interferes at different angles to draw conclusions about the film itself — how thick it is, for example. This new technique takes that kind of analysis one step further for light-emitting thin films.

"The key difference in our technique is we're looking at the energy as well as the angle and polarization at which light is emitted," said Rashid Zia, assistant professor of engineering at Brown University and one of the study's lead authors. "We can relate these different angles to distinct orientations of emitters in the film. At some angles and polarizations, we see only the light emission from in-plane emitters, while at other angles and polarizations we see only light originating from out-of-plane emitters."

The researchers demonstrated their technique on two important thin-film materials, molybdenum disulfide (MoS2) and PTCDA. Each represents a class of materials that shows promise for optical applications. MoS2 is a two-dimensional material similar to graphene, and PTCDA is an organic semiconductor. The research showed that light emission from MoS2 occurs only from in-plane emitters. In PTCDA, light comes from two distinct species of emitters, one in-plane and one out-of-plane.

####

About Brown University
Once the orientation of the emitters is known, Zia says, it may be possible to design structured devices that maximize those directional properties. In most applications, thin-film materials are layered on top of each other. The orientations of emitters in each layer indicate whether electronic excitations are happening within each layer or across layers, and that has implications for how such a device should be configured.

“If you were making an LED using these layered materials and you knew that the electronic excitations were happening across an interface,” Zia said, “then there’s a specific way you want to design the structure to get all of that light out and increase its overall efficiency.”

The same concept could apply to light-absorbing devices like solar cells. By understanding how the electronic excitations happen in the material, it could be possible to structure it in a way that coverts more incoming light to electricity.

“One of the exciting things about this research is how it brought together people with different expertise,” Zia said. “Our group’s expertise at Brown is in developing new forms of spectroscopy and studying the electronic origin of light emission. The Kymissis group at Columbia has a great deal of expertise in organic semiconductors, and the Shan group at Case Western has a great deal of expertise in layered nanomaterials. Jon Schuller, the study’s first author, did a great job in bringing all this expertise together. Jon was a visiting scientist here at Brown, a postdoctoral fellow in the Energy Frontier Research Center at Columbia, and is now a professor at UCSB.”

Other authors on the paper were Sinan Karaveli (Brown), Theanne Schiros (Columbia), Keliang He (Case Western), Shyuan Yang (Columbia), Ioannis Kymissis (Columbia) and Jie Shan (Case Western). Funding for the work was provided by the Air Force Office of Scientific Research, the Department of Energy, the National Science Foundation, and the Nanoelectronic Research Initiative of the Semiconductor Research Corporation.

For more information, please click here

Contacts:
Kevin Stacey
401-863-3766

Copyright © Brown University

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Quantum optics allows us to abandon expensive lasers in spectroscopy: Lomonosov Moscow State University scientists have invented a new method of spectroscopy November 21st, 2017

Nano-watch has steady hands November 21st, 2017

Nano Global, Arm Collaborate on Artificial Intelligence Chip to Drive Health Revolution by Capturing and Analyzing Molecular Data in Real Time November 21st, 2017

Nanoparticles could allow for faster, better medicine: Exposure of nanoparticles in the body allows for more effective delivery November 20th, 2017

Display technology/LEDs/SS Lighting/OLEDs

The next generation of power electronics? Gallium nitride doped with beryllium: How to cut down energy loss in power electronics? The right kind of doping November 9th, 2017

Atomic scale Moiré patterns to push electronic boundaries? November 1st, 2017

The secret to improving liquid crystal's mechanical performance: Better lubricating properties of lamellar liquid crystals could stem from changing the mobility of their structural dislocations by adding nanoparticles October 13th, 2017

Missing atoms in a forgotten crystal bring luminescence October 10th, 2017

The power of perovskite: OIST researchers improve perovskite-based technology in the entire energy cycle, from solar cells harnessing power to LED diodes to light the screens of future electronic devices and other lighting applications August 18th, 2017

Thin films

MIPT scientists revisit optical constants of ultrathin gold films October 20th, 2017

Govt.-Legislation/Regulation/Funding/Policy

EC Project Aims at Creating and Commercializing Cyber-Physical-System Solutions November 14th, 2017

Nanobiotix presented new clinical and pre-clinical data confirming NBTXR3’s significant potential role in Immuno-Oncology at SITC Annual Meeting November 14th, 2017

Leti Joins DARPA-Funded Project to Develop Implantable Device for Restoring Vision November 9th, 2017

Nanoshells could deliver more chemo with fewer side effects: In vitro study verifies method for remotely triggering release of cancer drugs November 8th, 2017

Discoveries

Quantum optics allows us to abandon expensive lasers in spectroscopy: Lomonosov Moscow State University scientists have invented a new method of spectroscopy November 21st, 2017

Nano-watch has steady hands November 21st, 2017

Nanoparticles could allow for faster, better medicine: Exposure of nanoparticles in the body allows for more effective delivery November 20th, 2017

ICN2 researchers compute unprecedented values for spin lifetime anisotropy in graphene November 17th, 2017

Announcements

Quantum optics allows us to abandon expensive lasers in spectroscopy: Lomonosov Moscow State University scientists have invented a new method of spectroscopy November 21st, 2017

Nano-watch has steady hands November 21st, 2017

Nano Global, Arm Collaborate on Artificial Intelligence Chip to Drive Health Revolution by Capturing and Analyzing Molecular Data in Real Time November 21st, 2017

Nanoparticles could allow for faster, better medicine: Exposure of nanoparticles in the body allows for more effective delivery November 20th, 2017

Tools

Nanometrics to Participate in the 6th Annual NYC Investor Summit 2017 November 16th, 2017

Nanometrics Announces $50 Million Share Repurchase Program November 15th, 2017

Nanometrics Board of Directors Names Pierre-Yves Lesaicherre President and CEO November 14th, 2017

Oxford Instruments announces winner of the 2017 Sir Martin Wood Prize for Japan November 14th, 2017

Military

Math gets real in strong, lightweight structures: Rice University researchers use 3-D printers to turn century-old theory into complex schwarzites November 16th, 2017

Promising sensors for submarines, mines and spacecraft: MSU scientists are developing nanostructured gas sensors that would work at room temperature November 10th, 2017

Leti Joins DARPA-Funded Project to Develop Implantable Device for Restoring Vision November 9th, 2017

Nanoshells could deliver more chemo with fewer side effects: In vitro study verifies method for remotely triggering release of cancer drugs November 8th, 2017

Energy

Inorganic-organic halide perovskites for new photovoltaic technology November 6th, 2017

Dendritic fibrous nanosilica: all-in-one nanomaterial for energy, environment and health November 4th, 2017

New nanomaterial can extract hydrogen fuel from seawater: Hybrid material converts more sunlight and can weather seawater's harsh conditions October 4th, 2017

Researchers set time limit for ultrafast perovskite solar cells September 22nd, 2017

Grants/Sponsored Research/Awards/Scholarships/Gifts/Contests/Honors/Records

Math gets real in strong, lightweight structures: Rice University researchers use 3-D printers to turn century-old theory into complex schwarzites November 16th, 2017

Oxford Instruments announces winner of the 2017 Sir Martin Wood Prize for Japan November 14th, 2017

A new way to mix oil and water: Condensation-based method developed at MIT could create stable nanoscale emulsions November 8th, 2017

Nanoshells could deliver more chemo with fewer side effects: In vitro study verifies method for remotely triggering release of cancer drugs November 8th, 2017

Research partnerships

Nano Global, Arm Collaborate on Artificial Intelligence Chip to Drive Health Revolution by Capturing and Analyzing Molecular Data in Real Time November 21st, 2017

EC Project Aims at Creating and Commercializing Cyber-Physical-System Solutions November 14th, 2017

Leti Joins DARPA-Funded Project to Develop Implantable Device for Restoring Vision November 9th, 2017

Nanoshells could deliver more chemo with fewer side effects: In vitro study verifies method for remotely triggering release of cancer drugs November 8th, 2017

Solar/Photovoltaic

Inorganic-organic halide perovskites for new photovoltaic technology November 6th, 2017

New nanomaterial can extract hydrogen fuel from seawater: Hybrid material converts more sunlight and can weather seawater's harsh conditions October 4th, 2017

Researchers set time limit for ultrafast perovskite solar cells September 22nd, 2017

Copper catalyst yields high efficiency CO2-to-fuels conversion: Berkeley Lab scientists discover critical role of nanoparticle transformation September 20th, 2017

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project