By Yolanda Smith, BPharm
The utility of quantum dots in continually expanding as more is discovered about how they work and their specific properties that can provide novel methods of doing things. One such use is in photovoltaic energy.
Traditionally, photovoltaic cells are composed of silicon are used to harness the solar energy of the sun. The technology of solar cells is advancing rapidly and cells using quantum dots are seen as a promising solution for the future.
Quantum dots are used to line the solar cell with a thin coating. Their natural ability to absorb solar light is harnessed, which is then transported as an electrical current to provide energy where it is required. The specific band gap of quantum dots corresponds to the frequency of sunlight, such that the light can be absorbed to excite the nanocrystal particles. This energy can then be converted and used as an electrical current.
Among the most beneficial qualities of quantum dots in photovoltaics, is their comparatively low cost, lightweight and versatile nature.
Unlike many traditional solar cells, quantum dot cells show considerable durability. They do not need high temperatures or an inert atmosphere to create energy and show no signs of degradation at all after five months in normal air conditions.
The manufacturing process of quantum dot photovoltaic cells requires considerably less energy than other types. The entire cell, excluding the electrodes at this point in time, can be deposited at room temperature under normal conditions, without the use of solution. This is advantageous as it minimizes manufacturing processes required with the transport of materials.
However, there is still work to be done before the utility of quantum dots will measure up to other techniques currently used for photovoltaic cells, such as silicon based cells.
Specifically, the efficiency of quantum dots is lower than industry standard rates, with only approximately 9% of sunlight energy being successfully converted into electrical energy. This is understandable given the short length of time quantum dots have been used in photovoltaic cells, in comparison to the six decades dedicated to the development of silicon-based cells. It is expected that subsequent research in the area will help to improve the efficiency of quantum dot photovoltaics.
The stability of quantum dots is not well understood and future research may help to explain this phenomenon so that it can be used to greater advantage. There has been an explosion of research in the field in recent years, which opens up the possibility of quantum dots utility and brings more questions to the surface for further research to discuss.
There is still significantly more work to be done before quantum dot voltaic cells may be offered on a commercial basis, but the potential they may carry for the future is undeniable. A great step forward has been made and over the coming years there is hope that quantum dot voltaic cells may provide an efficient and durable method of harnessing solar power.
Last Updated: Apr 28, 2015