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Professor in the Department of Engineering+44 (0) 191 33 42527


Short Bio

Dr Balocco is an Assistant Professor in Electronics in the School of Engineering and Computing Sciences at Durham University, appointed in November 2011. This position follows an appointment as a Research Associate at School of Electrical and Electronic Engineering at the University of Manchester. His research interests have included transport phenomena in self-assembled quantum dots, novel nanodevice architecture and circuit in organic and metal-oxide thin films, ultra-fast nanodevices for THz applications and large-area micro- and nano-fabrication techniques. More recently, his interest focuses on the interaction of thermal radiation with semiconductor nanodevices with applications envisaged in THz imaging and energy harvesting.

Converting radiant heat into electrical power
Schematic and image of a thermal rectenna

It is well known that every hot object radiates a great deal of energy in the form of far- and mid-infrared radiation. Battery chargers, heat from industrial machinery, domestic appliances and even the human body, all generate a large amount of this “low grade” –or wasted– energy; even a considerable part of the solar spectrum lies within this frequency region. A strong research and development effort, as well as a large injection of capital, has been made in order to envisage an effective way to harvest this energy with no CO2 expenditure. Unfortunately, current solid-state solar technology –namely photovoltaics– and thermophotovoltaics are unable to capture efficiently the energy radiated in the mid-infrared, and below, due to the physical limitations imposed by the semiconductors’ energy gaps used in their manufacturing. Although some successful result has been reported with thermoelectric devices, their efficiency is too low to be considered as a viable technology for energy harvesting [6] and the required materials, such as bismuth telluride (Bi2Te3), often pose environmental risks.

New devices based on the rectenna paradigm are quickly gaining acceptance as viable solutions for scavenging electromagnetic radiation. This idea is not new: it was initially proposed by Bailey in the early 70’s for direct conversion of sunlight as an alternative to solar cells. However, this approach relies on the availability of low-cost rectifiers –namely diodes– which can operate at very-high speed with very-low threshold voltage, which can be easily integrated with optical antennas. Due to the limited technology available at the time, the subject did not receive much attention from either the scientific community or industry.

The net power radiated per unit area by a hot body J at an absolute temperature T to a medium at room temperature T0 obeys the Stefan-Boltzmann law: J = σε(T4 -T0 4) where σ is the Stefan-Boltzmann constant and ε the body emissivity, the latter can often be approximated to 1 if the body surface is properly treated. The amount of available power is startling: an object at a temperature of 600 °C radiates 33 kW/m2, while an adult human body approximately 100 W. Obviously, not all the radiated power can be converted into useable electric power, and the theoretical efficiency limit will be investigated in WP4. The frequency spectrum emitted by a hot body is well described by Planck’s law of black-body radiation. A remarkable consequence, Wien’s displacement law, states that the frequency at which the power density is at a maximum is fmax = T × 58.8 GHz/K, where T is the body temperature in Kelvin. In the temperature range of interest, 300-600 °C, fmax ranges approximately between 30 and 50 THz. 

We recentely demonstrated a working prototype based on novel ultrafast nanodiodes coupled to infrared microantennas, which we fabricate in the electronic group clearoom (see figure): Y. Pan et al., "Micro rectennas: Brownian ratchets for thermal-energy harvesting", Appl. Phys. Lett. 105, 253901 (2014). Apart from being the first group to clearly demonstrate the convertion of radiant energy to dc power, we also proposed a model based on Brownian ratchets, which correctly accounts for the incoherent nature of thermal radiation.

Projects with the automotive industry are currently ongoing, aiming to recover efficiently the power lost as heat.

Prospective PhD students are welcome to get in touch directly for further information and for discussing funding opportunities.

Research Grants


  • (PI) EPSRC EP/N021258/1 “Nano-rectennas for heat-to-electricity conversion”, led by Durham University in collaboration with the University of Manchester. Grant value £712,468; Durham share £354,129. Start date 8/8/2016; end date 7/8/2019.
  • (PI) Royal Academy of Engineering Distinguished Visiting Fellowships DVF1415/2/95 “Tamm plasmon based optoelectronic devices”. Grant value £6,000. Start date 23/6/2015; end date 24/12/2015.
  • (PI) Thermal Energy Recovery From Combustion Engine Exhaust Pipes, EPSRC, £22k, 2014-06-26 - 2014-12-24
  • (CO-I) NOTEDEV ITN 2013, European Commission, £700k 2013-10-01 - 2017-09-30
  • (CO-I) Sensor Array for Terahertz Imaging in Non-destructive test (SATIN), TSB, £27k, 2014-10-01 - 2015-07-31
  • (PI) Electronic nanodevices for energy harvesting: a novel approach to thermal energy conversion, EPSRC, £98k, 2013-06-26 - 2014-06-25

Research interests

  • Rectennas for Energy Harvesting
  • THz technology
  • THz imaging
  • Semiconductor devices
  • Ultra-fast electronic transport mechanisms


Conference Paper

Journal Article


Supervision students