Strain-engineered Materials for use as Broad-spectrum Light Emitters & Collectors

Technology #15741

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Inventors
Professor Ju Li
Department of Nuclear Science and Engineering, MIT
External Link (web.mit.edu)
Xiaofeng Qian
Department of Nuclear Science and Engineering, MIT
Ji Feng
International Center for Quantum Materials, School of Physics, Peking University
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Christopher Noble
MIT Technology Licensing Officer - Clean and Renewable Energy
Patent Protection

Strain-Engineered Bandgaps

US Patent 9,595,624

Application

Photovoltaics, light emission, photocatalysis, and photon-detection.

Technology

This invention involves optoelectronic devices that can interact with light and facilitate the generation and collection of charge carriers, e.g., electrical current, associated with a broad range of wavelengths. Specifically, inhomogeneous strain as applied to atomically thin materials has been discovered to be an important vehicle to enable the collection and/or emission of a broad range of wavelengths as compared to prior materials operating at a single wavelength. This ability to interact with a range of wavelengths, as compared to a single wavelength, greatly increases the device's efficiency.

 In one example, an optoelectronic device may include a first optoelectronic material that is inhomogeneously strained. First and second charge carrier collectors are then electrically connected to the inhomogeneously strained material to collect charge carriers into the material to either generate a current or produce light. 

In addition to collecting and generating light, these materials can also be used to provide an engineered material for a range of different photocatalysis reactions using the same base material by simply adjusting the applied strain.

Problem Addressed

Typical photovoltaic materials are only capable of collecting a single wavelength of radiation to produce a current. This restriction of typical devises inherently limits the possible efficacy of a photovoltaic device. Further, unlike atomically thin materials, typical bulk materials are unable to sustain large enough elastic strains to significantly affect their ability to absorb different wavelengths of light before the onset of plasticity or fracture.

 Advantages

  • Controlled band gap in optoelectric materials at a low cost.
  • Multiple wavelengths of radiation can be utilized, thus increasing device efficiency.
  • Multiple photocatalysis reactions can be facilitated using the same material by using different applied strains.
  • Atomically thin membranes are a notable family of materials that exhibit ultrastrength qualities; for instance, they can resist inelastic relaxation up to a significant fraction of their ideal strength.