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The purpose of ERC Starting Grants is to support promising young researchers. The two-million euro funding has been granted for a five-year period. If Oksanen and his research group make a breakthrough, their work may result in an environmentally friendly solid state optical cooling solution that could be used to replace the mechanical cooling solutions of heat pumps and refrigerators.

Thermophotonics studies phenomena in which both electricity and heat are used to generate light energy. Oksanen's research group has performed ground-breaking work in the field of LED structures suitable for cooling and heat transfer. Making use of thermophotonic phenomena is possible when the photons emitted by a LED receive energy from the electricity supplied to the LED and also obtain heat from the system.

-      Efficiency is a slightly misleading term here, but LEDs can have an efficiency of over 100 per cent. In order for this to be possible, the external quantum efficiency of the semiconductor should be close to one, while the operating voltage should remain slightly below the voltage corresponding to the energy of the photons. This is what we are trying to achieve.

The research project will progress from creating computational models to manufacturing new semiconductor structures in the cleanroom facilities of the Micronova Centre for Micro and Nanotechnology. The main goal is to perform experiments that will prove the light-emission-based cooling phenomenon of electrically doped semiconductors.

-      To begin with, we will demonstrate the heat transfer effect in closed structures that include both a light-emitting component (LED) and a light-absorbing component, such as a solar cell. The idea is to increase light emission, or the quantum efficiency of the LED.

Optical cooling to replace Peltier elements

In the long run, the goal is to create optical cooling solutions to replace Peltier elements that are based on thermoelectric cooling. Peltier cooling is used in various applications, such as car coolers, but it is not very efficient.

-      In the best-case scenario, the efficiency of optical cooling could exceed the efficiency of mechanical cooling used in refrigerator compressors and heat pumps. This would mean major energy savings in both cooling and heating applications worldwide. Optical cooling solutions are more environmentally friendly because they do not require the use of harmful refrigerants. They can also be made to last as there are no moving parts.

Oksanen's research group works at the Department of Neuroscience and Biomedical Engineering at the School of Science. The foundation for the work to be carried out in the ERC project has been laid in the HighLight project of the Aalto University MIDE research programme and in the MOPPI project of the Aalto Energy Efficiency Research Programme.

Further information:

Jani Oksanen
Researcher, D.Sc. (Tech.)
Department of Neuroscience and Biomedical Engineering
tel. +358 50 512 4374
jani.oksanen@aalto.fi