Office of Technology Transfer – University of Michigan

Metallic Wire Grids as Transparent Electrode Fabricated by Roll to Roll Process

Technology #5223

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Researchers
Lingjie Jay Guo
Managed By
Joohee Kim
Licensing Specialist, Physical Sciences & Engineering 734.764.8202
Patent Protection
US Patent Pending
US Patent Pending

Drawbacks Of Using Indium-Tin-Oxide In Display And Photovoltaic Systems

Indium-tin-oxide (ITO) is widely used in display systems, photovoltaics, and in optical and conductive coatings. However, ITO is relatively expensive, and recent increases in the cost of indium have prompted a search for viable alternatives.

ITO also poses several technological barriers to the construction of large-area flexible and moldable photovoltaic (PV) devices and systems. ITO has limited flexibility and conductivity making it non-optimal for thin-film and flexible technologies. High quality ITO (especially high-conductivity ITO) requires high temperature annealing, which is incompatible with plastic-based flexible substrates. The poor conductivity of ITO films on flexible substrates reduces the fill-factor of devices, resulting in low power conversion efficiencies. ITO film is also brittle, and its poor mechanical stability can cause device failure when an ITO-coated flexible substrate is bent.

University of Michigan’s Technology To Replace Indium-Tin-Oxide In Display And Photovoltaic Systems

Researchers at the University of Michigan have developed a technology that overcomes the above issues associated with ITO. The technology makes use of a transparent and conductive electrode based on metallic nanostructures. This transparent metal electrode (TME) takes the form of a periodic nanoscale metal wire grid fabricated by nanoimprint lithography (NIL). The TME has high optical transparency and good electrical conductivity. Unlike with ITO, these properties can be adjusted independently by changing the metal line width and thickness in the metal grid structure. The TME also displays improved mechanical flexibility and durability.

Additionally, the nanoscale metallic nanowire structures exhibit unique optical properties due to the excitation of surface plasmon resonance (SPR), which can be exploited in specially designed plasmonic color filters and polarizers.

Applications

  • Touchscreen applications
  • ITO replacement in OLED screens, and photovoltaic systems
  • Plasmonic color filters and polarizers
  • High input power applications like 3D projection displays

Advantages

  • Reduced cost compared to ITO-based approaches
  • High optical transparency and electrical conductivity
  • Increased transmission efficiency
  • Simplified color filter design and fabrication