A research team led by Prof. Pak Tae-ho of POSTECH has developed new technology for synthesizing nano tubes.
Scientists have developed a new technology that can significantly increase the efficiency of solar cells compared to current technologies using the TiO₂, which is rapidly being utilized in the nanotechnology area thanks to its low price and excellent stability.
The research team led by Prof. Pak Tae-ho of chemical engineering at POSTECH developed a technology that can easily synthesize TiO₂-based nano tubes, whose two ends are opened, in large volume by etching desired parts after treating the TiO₂ with heat in two ways.
This new technology is expected to significantly contribute to improving the performance of solar cells as it enables an expanded area of solar cells and increases the charge collection efficiency by up to 90%.
Scientists have been using the anode oxidation method in producing TiO₂-based nano tubes thus far, but this method is unable to make large area solar cells because nano tubes are either broken or rolled in the separation process. And one end of the nano tubes is closed even though they successfully prevent the breaking or rolling phenomenon.
In the case that one end of the nano tube blocks, it is difficult to use for sensoring as it does not allow electrolyte to move freely. For this reason, many research teams have been competing over the developing technology of mass producing nano tubes with two open ends.
The research team led by Prof. Pak Tae-ho successfully produced TiO₂-based nano tubes whose two ends are opened by chemically cutting the part that is not enhanced with stability after reinforcing the stability of the desired nano tube layer by treating it with heat.
The new technology is particularly noteworthy as the heat treatment method is simple and it can sharply improve economic efficiency if used in the etching process of hydrogen peroxide that is richly available.
When the nano tubes developed by the research team are used as the working electrode of solar cells, the charge collection efficiency increases by 75~90% over the nano particle-based electrode, and its photovoltaic conversion efficiency also rose to 8.6% from the previous 7.3%.
As it enables the precise control of the size and length of nano tubes, the new technology is expected to be widely used in various areas, including that of the photocatalyst and chemical sensor.
Prof. Pak Tae-ho said, “Since TiO₂-based nano tubes are widely applied for photocatalyst, the sensor and battery as well as the solar cell, the technology of controlling the structure of nano tubes is very highly evaluated. International research communities show keen interest in the new technology since it can increase economic efficiency while paving the road for mass production through the adoption of simple processes.”
Meanwhile, the new technology of synthesizing nano tubes developed by the Prof. Pak-led research team was published by ‘Chemical Communications’ of the U.K.’s Royal Society of Chemistry, an authoritative journal in the chemistry area, as the cover story.