Energy generation

Read all about our energy research including energy conversion, triboelectric and thermoelectric generation.

Flexible organic solar cells

Hybrid SCs offer numerous application possibilities. They can be rolled and used as a lightweight solar charger or integrated in the facades and windows of buildings improving the aesthetic appearance while generating green electricity at low cost.

Energy conversion

From our inception, we have been actively involved in research on energy conversion techniques. The research has focused on two fundamental aspects; Photovoltaic devices for converting solar radiation to electricity and light emitting diodes (LEDs) converting electrical energy to optical radiation with high efficiency.

Photovoltaic device research has been conducted on a number of themes. The research ranges from inorganic material based thin film semiconductor solar cells to fourth generation organic-inorganic hybrid thin film devices. We are concentrating on utilising the advantages of organic and inorganic material systems in hybrid photovoltaic systems, using our core expertise in nanotechnology.

Carbon nanotubes are utilised in these novel device architectures, as solution processable, flexible electrodes for photo-generated charge collection and transport. Inexpensive nanostructured material systems such as zinc oxide are also being explored for charge collection and transport to the electrodes. Laser nanostructured material systems are utilised for harnessing their optical properties to further improve these systems.

The research is aimed at improving the efficiencies of solution processable thin film photovoltaics, while keeping the potential cost low in utilising printing technologies, which are on the verge of becoming a commercial reality, in a commercially relevant approach, applying large area photovoltaic mini-modules.

We have also been innovating organic and polymer light-emitting diodes (OLEDs and PLEDs) by combining commercially available materials with novel carbon-based technologies, including carbon nanotubes and graphene. The addition of these novel materials to OLEDs/PLEDs can enhance brightness, device efficiency, and lifetime.

In addition, we have a number of other research interests in utilisation of nanotechnology for energy conversion. These include research on energy storage such as super-capacitors, hydrogen storage and membrane development for osmosis which leads to enhanced chemical to electrical energy conversion.

Thermoelectric generation

Thermoelectric materials or devices are those that convert energy from heat into an electrical potential when a temperature gradient is induced between the two ends of a material.

As heat is a by-product in many modern scenarios, the range of application to generate additional thermoelectric energy is vast. This includes industries such as; automotive, textile (i.e. wearable electronics), aerospace, space and power generation.

However, current thermoelectric devices are composed of semiconductor materials which tend to be toxic, inorganic and expensive to manufacture.

In our current project, carbon nanotubes are shown to be an effective alternative thermoelectric material with properties that include mechanical flexibility, low manufacturing cost and non-toxicity. A common technique used to functionalise carbon nanotubes while doping to exhibit n-type and p-type semiconducting properties, is typically achieved by introducing chemical compounds such as polyethylenimine.

A high figure of merit for thermoelectric devices (i.e. efficiency rating) requires a high Seebeck coefficient, high electrical conductivity and a low thermal conductivity. We measure these parameters within a custom made thermoelectric analysis device, which features a vacuum controlled chamber, with a remotely controlled heating element and active cooling system, providing the necessary high temperature gradients. This set-up allows us to explore thermal conductivity and thermoelectric properties of next generation flexible thin film materials, such as carbon nanotubes and other carbon based materials.

Photoluminescence Quenching in Carbon Nanotube-Polymer/Fullerene Films: Carbon Nanotubes as Exciton Dissociation Centres in Organic Photovoltaics
N. Aamina Nismy, K. D. G. Imalka Jayawardena, A. A. Damitha T. Adikaari and S. Ravi P. Silva.

Triboelectric generation

Triboelectricity is a commonly observed phenomenon in day-to-day life, it occurs when two surfaces contact or rub against each other to generate static charge, a classic example being rubbing a balloon and sticking it to the wall.

Triboelectric Nanogenerators (TENGs) utilise the generation of static charge to effectively convert mechanical energy in to electrical energy. These devices have exhibited the potential to generate high power outputs at high efficiency and low cost. TENGs have been successfully demonstrated as a suitable option for applications in energy harvesting as well as self-powered sensors, paving the way for smart textiles.

We are investigating the fundamental sciences of TENGs as well as their potential applications. By employing custom built sub-micron precise automated motion control systems, and ultra-sensitive electrical characterisation units, we are performing high precision characterisations of these devices, allowing us to further develop the necessary material advances required to meet the current consumer demands.

  • Theoretical study of the working principle of TENGs
  • Characterisation of the fundamental behaviour of different modes of TENG structures
  • Enhancing of the power output of TENGs using nanomaterial-based modifications
  • High efficient textile-based TENGs for wearable electronics
  • Electrospun nano-fibre TENGs.

Get in contact

If you'd like to learn more about this research then please email Professor Ravi Silva.

Flexible smart surfaces for augmented indoor communications (SURFAS) project

This SURFAS project aims to develop efficient radio frequency (RF) energy harvesters and zero-power consuming smart electronic surfaces that are able to reflect and enhance electromagnetic radiation (EM) and improve the accessibility of wi-fi signals in buildings.

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Nanoelectronics Centre
Advanced Technology Institute
University of Surrey