NIST demonstrates quick testing of organic materials with off-the-shelf technology

Organic materials are attractive to the solar industry because of their comparative low cost and physical flexibility. NIST findings reveal how to test a candidate organic material's viability at converting light to electricity both quickly and directly. Credit: Cappello/Georgia Tech, Courtesy National Renewable Energy Lab 

 http://phys.org/news/2015-07-nist-quick-materials-off-the-shelf-technology.html#jCp

Hunting for the best material from which to build organic solar cells can be like seeking the proverbial haystack needle, but now scientists at the National Institute of Standards and Technology (NIST) and the Naval Research Laboratory may have a better search tool for the nascent industry.

The team's research findings in Nature Communications show it is possible to test a candidate material quickly and directly, using off-the-shelf laser technology. The method bypasses the costly, time-consuming step of constructing a prototype solar cell for each material to be evaluated.

"We'd like to give companies and manufacturers an alternative to trial and error," says NIST research chemist Ted Heilweil. "It takes a long time to develop photovoltaic materials for market. Screening them using our method would be much faster."

Organic materials (e.g. plastics) hold a particular attraction for the solar industry, largely because of their comparative low cost and physical flexibility. Organics inspire the possibility of one day painting an inexpensive solar array onto most any surface, even one that bends and moves, and simply replacing it with a fresh coat when it wears out.

At this point, organics are far less efficient at converting sunlight to electricity than traditional silicon-based technology, but ideas for better materials come at a fast clip. Unfortunately, sifting through these candidates and zeroing in on the most promising ones is expensive and arduous. Because it entails building a prototype cell for each prospective material, relatively few candidates get tested.

The team's new method sidesteps this problem by using ultrafast lasers to probe a candidate material's abilities directly—and without electrical contacts. They found that when shining pulses of visible light onto a sample to mimic the sun, they could probe the sample's electronic behavior with a second laser pulse near the microwave range of the spectrum. When the sample absorbs these "terahertz" waves, its properties change in easily detectable ways. Just how the terahertz pulse changes is dependent on the material's viability at converting light to electricity.

To test their method, the team looked at a number of mixed organic molecules and polymers whose abilities were well-understood from conventional prototyping.

"We looked at small organics and polymers that people in the solar industry have been using as benchmarks, and we saw the same relative behavior with our terahertz measurements," Heilweil says. "We're pretty confident that our method can tell you what is useful to know."

The team is using the method as part of its own ongoing materials search, Heilweil says.

 Explore further: NIST measurements may help optimize organic solar cells

More information: "Hot photocarrier dynamics in organic solar cells." Nature Communications, 6. Article 7558.Published online July 16, 2015. DOI: 10.1038/ncomms8558

Abstracts Nuclear Gauges, Nondestructive Evaluation, Materials Analysis, Chemical Analysis of Art (thanks to bucktailjig!)

There is always reason to be excited about the developments in Terahertz technology. The following are just a small portion of the many, abstracts relating to on-going studies and projects which are certain to lead to commercial products, sooner or later. ( I want to believe in sooner ).

Time-Domain Terahertz Process Control Measurements to Replace Nuclear Source Gauges
Basic Information
Abstract Number:
1910-2


Author Name:
Jeffrey S White
Affiliation:
Picometrix LLC
Session Title:
Product Status / Process Stream Measurements
Event Type:
Oral
Event Title:
Time-Domain Terahertz Process Control Measurements to Replace Nuclear Source Gauges
Presider(s):
Woodman, Michael
Start Time:
08:50 AM ( Slot # 2 )
Date:
03/11/2009
Location:
S505a
Keywords:
Instrumentation, Paint/Coatings, Paper/Pulp, Process ControlCo-Authors
Name
Affiliation
Chernovsky, Artur
Picometrix LLC
Fichter, Greg
Picometrix LLC
Zimdars, David
Picometrix LLCAbstract Content
This presentation will detail Time-Domain Terahertz (TD-THz) instrumentation to address a number of measurement applications typically made with nuclear source gauges (alpha, beta, gamma). The goal of this Department of Homeland Security funded grant is to develop a functional economic technology to replace nuclear source gauges, thus removing the need to have such “orphaned” nuclear material in the commercial sector.Measurements will be demonstrated for basis weight (grams per square meter), thickness and density monitoring in manufacturing / process control. Examples include paper manufacture and conversion processes, multiple diverse coating applications and consumer product (adhesives on tape) manufacturing processes. TD-THz also allows nuclear gauge like measurements in industries that cannot use such gauges (e.g., PAT measurements for pharmaceutical manufacturing).It will be demonstrated that TD-THz measurements can be made at a much higher rate with better precision. The higher speed measurements allow better measurement of “cross machine” variations in web type manufacturing applications.Terahertz measurements extend past the capabilities of nuclear gauges. A significant advantage of the TD-THz is the ability to study multilayer and composite structures. With reflection geometry measurements, physical properties (e.g., mass, thickness) can be simultaneously determined for multiple layers of a sample. Non-contact “caliper” whole sample thickness measurements are demonstrated. This measurement does not require any prior knowledge of the sample’s composition.The TD-THz sensors are coupled through flexible fiber optic and electrical cables, allowing the sensors to be easily placed at process measurement points. All measurements are completely safe for personnel and samples.
____________________________


Advanced THz Materials for Nondestructive Evaluation (NDE)
New Phase 1 SBIR . This fits right in with Bob Sacks (Director, Molecular Beam Epitaxy, Picometrix LLC, an API Company) field of expertise. When acheived this will enhance all other projects and applications, and hopefully arouse interest from the TSA to go ahead and fund a TSA phase ll to adopt & integrate our Thz technology.

Proposal #:
F083-083-0876
DoD Submission #:
F083-083-0876
Phase:
I
Program:
SBIR
Proposal Title:
Advanced THz Materials for Nondestructive Evaluation (NDE)
AF Sol Topic #:
AF083-083
DoD Technology Area:
Materials / Processes
Solicitation #:
08.3
Gov't Managing Office:
RX
Agency:
AF
Gov't Sponsoring Office:
Topic Title:
Advanced THz Materials for Nondestructive Evaluation (NDE)
Award Details
Status:
Active
Amount:
100000
Contract:
FA8650-09-M-5425
Start:
1/12/2009 12:00:00 AM
End:
10/12/2009 12:00:00 AM
Annual Report FY:
Transition Success Story written?
Impact Story Submitted? No
HUBZone:
No
TRL Level:
TRL Application:
DTIC Rpt. Date:
DTIC Rpt. Num.:
DTIC Accession Number:
Firm Details
Firm:
Picometrix LLC
Socially & EconomicallyDisadvantaged Business?:
No
Address:
2925 Boardwalk
Woman Owned?:
No
Veteran Owned?:
No
City:
Ann Arbor
Disabled Veteran Owned?:
No
State:
MI
HBCU/MI:
No
Zip:
48104
HBCU/MI Name
Employees:
174
Contact Information
Project Manager Name:
Dr. David Zimdars
Project Manager Title:
Manager of Terahertz Development
Project Manager Phone:
(734) 864-5639
Project Manager Email:
dzimdars@picometrix.com

Corp Official Name:
Mr. Robin F. Risser
Corp Official Title:
President and General Manager
Corp Official Phone:
(734) 864-5605
Corp Official Email:
rrisser@picometrix.com
Appendix B
Abstract:In this Phase I project, we will demonstrate the improvement of the time-domain-terahertz (TD-THz) transmitter output power of low temperature grown indium gallium arsenide (LT-InGaAs) based epitaxial layer structures excited by the 1060 nm lasers, such as that employed in the T-RayTM 4000 TD-THz instrumentation system. Prior to this SBIR proposal, Picometrix has developed and commercialized 1060 nm driven LT-InGaAs photoconductive material with performance equivalent to traditional 800 nm driven low temperature grown gallium arsenide (LT-GaAs). The goal of this Phase I SBIR project will be to increase the electric field within the THz transmitting antenna at least 10 times over Picometrix’s current LT-InGaAs (or LT-GaAs) antenna by developing an enhanced LT-InGaAs photoconductive material. This emphasis on epitaxial growth and microfabrication during the first phase will provide the basis for a high-sensitivity THz transceiver that will make stand-off non-destructive evaluation (NDE) imaging possible during Phase II.
Benefits:In phase II we will package the enhanced “high performance” LT-InGaAs transmitter materials into the Picometrix’s standard telecommunications style miniature fiber pigtailed modules. These modules will provide greater than 10 times the electric field (and thereby a 10x increase in signal to noise) over the current generation of LT-InGaAs modules (or LT-GaAs modules). A Phase II prototype NDE stand-off imaging monostatic reflection TD-THz transceiver with 3-5 meter stand-off will be constructed, utilizing the new high performance modules. This will allow inspection of aircraft from the ground, without having to bring the instrument up near to the aircraft skin.
Keywords:Terahertz, Non Destructive Evaluation, molecular beam epitaxy, imaging

_____________________________________

FTIR, Sum Frequency and Terahertz-Materials Analysis
Basic Information
Abstract Number:
170-8


Author Name:
Jeffrey S White
Affiliation:
Picometrix LLC
Session Title:
FTIR, Sum Frequency and Terahertz-Materials Analysis
Event Type:
Oral
Event Title:
Time-Domain Terahertz Data Deconvolution Analysis for the Improved Measurement of Coating Thickness, Sample Mass, Density and other Applications
Presider(s):
Scandone, Marie
Start Time:
03:35 PM ( Slot # 9 )
Date:
03/08/2009
Location:
S504d
Keywords:
Data Analysis, Instrumentation, Paint/Coatings, Process ControlCo-Authors
Name
Affiliation
Chernovsky, Artur
Picometrix LLC
Fichter, Greg
Picometrix LLC
Zimdars, David
Picometrix LLCAbstract Content
This presentation will detail Time-Domain Terahertz (TD-THz) measurements and subsequent deconvolution analysis of THz time-domain data to significantly improve the measurement precision. These analysis methods directly improve the ability of TD-THz to make sample physical properties (e.g., basis weight, mass, thickness, density) for both laboratory and process control measurements. Additionally the method improves the appearance of data visualization (e.g., B-Scan) and the quality of imaging applications.TD-THz systems emit essentially single cycle pulses (1 ps width) of EM radiation. As an example, reflections of this pulse can be detected from all interfaces of a single or multilayer sample during the manufacturing process. The timing of these interfaces can be used to measure layer mass, thickness, density, etc. and thus provide process control or PAT capabilities.As will be presented, deconvolution analysis methods allow significantly improved robust measurement, with higher precision, of the time of the THz reflections. As the time-of-flight data is used to determine sample properties, this method directly leads to improved sample measurements. The analysis can be applied in real time and thus can be used in process control measurement applications (e.g., PAT for Pharmaceutical manufacturing).After deconvolution, a subsequent convolution with a prescribed pulse shape (e.g., Gaussian) significantly improves data visualization for B-Scans and for imaging applications.The TD-THz sensors are coupled through flexible fiber optic and electrical cables, allowing the sensors to be easily placed at process measurement points. All measurements are completely safe for personnel and samples.

________

Chemical Analysis of Art and Archaeological Objects
Basic Information
Abstract Number:
140-1


Author Name:
Jeffrey S White
Affiliation:
Picometrix LLC
Session Title:
Chemical Analysis of Art and Archaeological Objects
Event Type:
Oral
Event Title:
Time-Domain Terahertz Detection of Hidden Artworks
Presider(s):
Frederick, Kimberley
Start Time:
01:00 PM ( Slot # 1 )
Date:
03/08/2009
Location:
S505a
Keywords:
Art/Archaeology, Imaging, InstrumentationCo-Authors
Name
Affiliation
Duling, Irl
Picometrix LLC
Fichter, Greg
Picometrix LLC
Fukunaga, Kaori
NICT
Jackson, Jae B
Picometrix LLC
Menu, Michel
Louvre Museum
Whitaker, John
Picometrix LLC
Zimdars, David
Picometrix LLCAbstract Content
This presentation will detail Time-Domain Terahertz (TD-THz) investigations of detecting hidden works of art. Study of frescoes hidden under plaster in the 12th century Church of Saint-Jean-Bapitste in Vif France will be presented.Most dielectric materials are transparent to THz, thus it is possible to generate images through the plaster material. The reflectance and absorbance of materials used in frescoes and other art works (e.g., graphite) can vary in the THz region. Measurements through the plaster can record the reflection differences due to the differing pigments, binders, substrates and other materials of the artwork. Thus, the artwork under the plaster can be imaged. Studies of paintings, stained glass and parchment art objects will also be consideredThe presentation will also consider laboratory studies of THz properties of a wide range of the pigments, binders and other material used for both historic, recent and preservation artworks (THz spectra database).TD-THz systems emit essentially single cycle pulses (1 ps width) of EM radiation. Reflections of this pulse can be detected from all interfaces of a multilayer dielectric sample. The timing of these interfaces can be used to measure layer mass, thickness, etc.The TD-THz sensors are coupled through flexible fiber optic and electrical cables, allowing the sensors to be easily scanned over a very wide area. Umbilicals as long as 30 m have been delivered. All measurements are completely safe for personnel and samples.