Amazing pictures Quantum Dot Solar Cells

Amazing pictures Quantum Dot  Solar Cells.

A University of Toronto team led by Professor Ted Sargent has reported the development of the first two-layer quantum dot solar cell, that can be a game changer in the field of solar energy. The team has used two different specification of colloidal quantum dots ( CQS) , one tuned to absorb the visible part of the solar energy, and the other to absorb the infrared and near-infrared part of it, increasing the theoretical junction efficiency from 31 percent to 42 percent.

The conventional bulk silicon solar cells can only absorb energy from the visible spectrum of sunlight. The rest of the energy is passed through unabsorbed on poorly absorbed.The PbS ( Lead Sulfide) colloidal quantum dots, used by the Toronto team, have the advantage of being capable of being tuned to absorb different parts of the solar spectrum.
Combining two layers into a “tandem junction” has been attempted earlier too, but the problem had always been the resistance at the junction that led to losses. The Toronto team has come up with a solution to this problem by using a combination of four metal oxides in a cascaded transition layer that has kept the resistance “nice and low” as Prof Sargent puts it. The team has also chosen transparent oxides to permit the sunlight to pass through the lower layer.
The team is reported to have applied the CQS in layers on a Tin Oxide coated glass plate in ambient air and temperature conditions. Since the process does not need specialised equipment, it could eventually be as easy to apply as spraying on. The technology also permits increasing the number of layers to 3 or 4 that could push the theoretical junction efficiency as high as 84 percent.
While the theoretical junction efficiency has been increased to 42 percent, the Toronto team’s first two layer cell has an efficiency of only a tenth of that at 4.2 percent. The Toronto team is confident that in the next 5 years, this efficiency will be increased to 10 percent. The lower efficiency of quantum dot cells will be offset by their lower costs both in manufacture and application.

Reef Explorer By Gert-Jan van Breugel

It was a landmark event in the history of marine technology, when the exclusively solar powered catamaran Sun21 crossed the Atlantic Ocean in 2007. Now, clean solar power is literally going to leave its mark undersea, rather than over-sea. And it is going to do that with the help of the unconventionally new and adroitly conceived Reef Explorer. Contrived by Gert-Jan van Breugel, the solar powered electric marine craft would allow its passengers to enjoy the wondrous and vibrant scenery of the underwater life of our seas, oceans and lakes.


Conceptualized specifically for beautiful locations of coral reefs (and hence the name Reef Explorer) around the equator of the world, this advanced piece of machinery is all set to fulfill the economic niche for tourism market with a adamantly ‘green’ virtue. The distinctive design integrates a noticeably transparent hull, which will act as a window to the underwater view. It is flanked by two other wing like hulls (with propellers), thus completing the multi-hull system for reducing the effect of drag through water.

The whole body is composed of a light, sturdy and durable plastic called polyethylene. The production procedure incorporates an advanced technique known as roto-molding, which is a low-pressure plastic forming process that utilizes high temperature and biaxial rotation for to produce hollow one-piece parts. The previously mentioned transparent hull will consist of two polycarbonate sheets (a material used for bulletproof glasses and fighter jet cockpits).

Now, at last, coming to the ‘green’ part, this remarkable contraption will incorporate solar cells for clean electricity generation. According to the designer, this will have a two-fold advantage. Firstly, the clean propulsion mechanism powered by solar energy would cause no harm to the endangered eco-systems of coral reefs. Secondly, as already mentioned the craft will specifically be used in the equator regions. This is because the integrated solar cells will perform much better due to high sun intensity (in equators), especially with the sun’s angle being almost perpendicular.

The craft will be powered by two silent 12-volt electric motors, whereas the solar panels will be mounted on each side of the wing hulls. The excess energy generated by the cells can even be stored in four deep cycle batteries, and used during emergency cases (they can run for continuously 6 hours).




Designer: Gert-Jan van Breugel