Periyasamy Thilakan, Associate Professor, Department of Green Energy Technology, Madanjeet School of Green Energy Technologies, Pondicherry University, has been granted two patents by the Government of India for inventions in the domain of research on solar cells and nano materials.
The patents, granted under the Patents Act, 1970, will have a validity of 20 years, a press note from the university said.
One of the patented works, ‘Preparation of Luminescent Nanocrystalline Indium-tin-oxide (ITO)’ by Mr. Thilakan and a team of researchers at the Department of Green Energy Technology deals with the preparation of ITO nanocrystalline active light emitting layers.
As of now, the LED bulb manufacturing utilises the light emitted from the Gallium Nitride (GaN) that falls into the UV-A band width of emission, which is further converted into white light by phosphors. This white light is reported with poor colour vision called as colour rendering index (CRI).
The capable emission wavelength of ITO found in the UV-B was around 280-315 nm with the potential to improve the coloured vision. In this patent, the methodology for the preparation of defect free ITO nano crystallites capable of emission at the room temperature was invented.
Application of nano crystallites for the LED fabrication is expected to emit the white light having more colour rendering index, the university said.
The other patent, ‘Preparation of wide band TiO2 Antireflection coating for Silicon Solar Cells’ by the team led by Mr. Thilakan involves a process for the preparation and deposition of TiO2 nanoparticles on the etch-optimized p-type silicon substrates suitable for solar cell fabrication.
Solar cell is a current generator and its capacity is directly proportional to the absorbed number of photons with the energy capacity greater or equal to the bandgap of the semiconductor used. Hence, any loss of photon by reflection is the loss of output.
Till now, the silicon solar cell reported with the highest efficiency of 25.0 ± 0.5% results in the reflection losses of about 16% in the UV illumination.
Using the patented process for the optimisation of the surface of p-Silicon substrate, the preparation and deposition of TiO2 nanocrystal line layers results in flat band antireflection from the UV wavelength to the band edge wavelength of silicon.
This combination of nano TiO2/textured silicon results in the reflection of incident light less than 10% in the UV range, which is less than the reflection of the best silicon solar cell reported so far, the university press note said.