New ORNL Method Could Unleash Solar Power Potential
March 16, 2016 | ORNLEstimated reading time: 2 minutes
Measurement and data analysis techniques developed at the Department of Energy's Oak Ridge National Laboratory could provide new insight into performance-robbing flaws in crystalline structures, ultimately improving the performance of solar cells.
While solar cells made from light-harvesting perovskite (an organic-inorganic hybrid) materials have recently eclipsed the 20 percent efficiency mark, researchers believe they could do better if they had a clearer picture of energy flow at the nanometer scale. The ORNL discovery, described in a paper published in ACS Photonics, synchronizes microscopy, ultra-short pulses of laser light and data analytics to extract images with single-pixel precision, providing unprecedented detail.
"If we can see exactly and in real time what is happening, we can map out the electronic processes in space instead of relying on snapshots gleaned from spatial averages," said Benjamin Doughty, one of the authors and a member of ORNL's Chemical Sciences Division.
Armed with information about what electrons are doing inside the material, researchers believe they can make improvements that lead to solar cells that are more efficient and potentially less expensive.
"With conventional approaches of studying photovoltaic materials, we are unable to accurately map out electronic processes and how electrons are getting lost," Doughty said. "Those processes can translate into losses in efficiency."
The experiment consists of optically pumping the thin film sample with a 50 femtosecond -- or 50 millionths of a billionth of a second -- laser pulse and then measuring changes in light absorption with a second laser pulse in the material. The technique, called femtosecond transient absorption microscopy, consists of a tabletop of lasers, optics and a microscope. The net result is a pixel-by-pixel map of the material being studied and information researchers can use to improve performance.
"The ability to identify what will be created after the solar cell absorbs a photon, either a pair of free charges or their bound form called an exciton, is crucial from both fundamental and applied perspectives," said co-author Yingzhong Ma, who led the research team. "We found that both free charges and excitons are present, and the strength of our approach lies in not only identifying where they are but also determining what their relative contributions are when they are both present at a given spatial location."
A key remaining challenge is to understand what causes the observed spatial difference, said Ma, so he and colleagues are exploring an all-optical imaging approach that would allow them to correlate electronic dynamics with underlying structural information. This approach may also help researchers map and understand perovskite degradation issues associated with moisture. Ma noted that this must be resolved before solar cells based on this class of materials can be successful.
Suggested Items
Ansys’ Collaboration with Schrödinger will Accelerate Materials Development with Unprecedented Multiscale Simulation
05/09/2024 | ANSYSAnsys and Schrödinger are collaborating to deliver an ICME approach that bridges the gap between materials discovery and product development.
2024 Apple iPad Pro Estimated to Ship Between 4.5 to 5 Million Units
05/08/2024 | TrendForceApple’s recent product launch in May introduced a lineup of new tablets featuring advanced AMOLED screens. Notably, the Pro version boasts a dual-layer tandem structure designed to address the longstanding challenges of screen burn-in and lifespan that are common with AMOLED displays.
AIM Solder Signs Shinil Fl Ltd. as New Distributor for Korea
05/08/2024 | AIM SolderAIM Solder, a leading global manufacturer of solder assembly materials for the electronics industry, is pleased to announce a new distribution partnership with Shinil Fl Ltd., a prominent supplier of technological solutions in the SMT and semiconductor sectors.
IDTechEx Discusses Low-Loss Materials: The Enabler of Future Connected Vehicles?
05/06/2024 | IDTechExFuture connected vehicles will offer future drivers a safer, smoother, and more convenient driving experience. Not only will drivers get access to more navigation and entertainment options, but they will also gain access to safety technologies that will potentially reduce accidents, improve congestion, and reduce emissions globally by allowing vehicle safety systems to communicate with each other and with city traffic infrastructure.
LQDX Divests Aluminum Soldering Business - Mina™ - to Taiyo America Inc.
05/02/2024 | PRNewswireLQDX, formerly known as Averatek Corp., developer of high-performance materials for advanced semiconductor manufacturing, today announced that it has divested its aluminum soldering business – known as MinaTM – to Taiyo America Inc., a global market leader in advanced electronic materials.