GreEnergy will integrate nano-optical antennas with nano-rectifiers (rectennas) and a micro-energy storage component, on a single microchip

Problems to be solved

More than 70% of the energy we require is produced out of bio fossil fuels which cause severe damage to our planet by contributing to global warming. The search for clean energy resources is underway but still only accounts for less than 20% of the total energy market.

In addition, the exponential demand for electronic devices, with better performance and expanded functionality, requires more power to operate. The integration into these devices of an energy harvesting/storage system based on solar energy is a big step towards developing sustainable self-powering electronics.

However, the photovoltaic (PV) solar energy technologies currently have low efficiency and relatively high cost. GreEnergy aims to solve this issue by prototyping a self-powering system based on optical nano-antennas which can harvest solar energy with very high efficiency, rectify the AC signal and use it to charge a micro-supercapacitor.

Our approach to develop optical nano-antennas for solar energy harvesting

Optical rectenna

  • Optical weideband antenna operating withint the visible frequencies, with over theoretical 90% efficiency
  • Nano-rectifier of the AC signal into DC signal with high conversion efficiency, to supply a more-steady power source to the system
  • 2 options: graphene geometric diodes versus metal-insulator-metal (MIM) diodes


  • I/O ciurcuitry at the interface between rectenna and energy storage unit, stabilizing and filtering the diode output
  • Circuit design and simulation, using Computer Aided Design (CAD) assisted circuital and electro-magnetic simulations
  • Simulation of the full system level circuitry

Energy storage (self-powering system)

  • Micro-supercapacitator charged by the harvested energy from the rectenna, with high capacitance and very long cycle life
  • Optimising electrode and electrolyte materials for this particular application

System integration & demonstration

  • Develop process for on-chip integration of antenna/rectifier with energy storage device and interface circuitry
  • Fabricate the system
  • System level simulation of components
  • Develop prototype of integrated system, demonstrating successful charging of the micro-supercapacitator by the antenna/rectifier system

Our key objectives

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Achieve lab scale technology validation at the system level, by demonstrating a prototype achieving 20-40% efficiency for the integrated components
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Benchmark the technology for future development and commercialisation, aiming at a 60% system efficiency
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Fair deal to consumers, with a system cost below €100 per 1 m2, accelerating clean energy market penetration and strengthening the EU and worldwide leadership on renewables energy

Areas of exploitation and applications

Successful completion of the development will lead to a full-scale development stage maturing of the system for commercialisation via solar cell companies, institutes and consumer markets.

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Energy harvesting

  • Energy suppliers: centralised power plant
  • Solar cell related companies: replace the current semiconductor-based solar photovoltaic cells
  • Companies of electronic and micro-electronic devices

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Internet of Things

  • Free-space optical communication: wireless transmission of data for telecommunications or computer networking
  • Optical sensors: smartphones (screen brightness), pipeline monitoring, civil and transportation (bridge, dam, airplane monitoring…)

Future applications might also include biosensing and biomedical nano-communication.

Further reading

  1. Internet of things (IoT): Internet of things, Wikipedia,
  2. Energy harvesting: The How and Why of Energy Harvesting for Low-Power Applications, All About Circuits,