The sharp Xray vision of DESY’s research source of light PETRA III paves the way for new technique to produce cheap, varied and versatile double solar cells. The method made by scientists from the Technical University using Denmark (DTU) in Roskilde could very well reliably produce efficient tandem debit solar cells of many metres in length, together around senior researcher Jens Watts. Andreasen reports in the journal Enhanced Energy Materials.
The scientists practiced a production process, where the various layers of a polymer (plastic) empedrar cell are coated from a lot of solutions onto a flexible substrate. Using this method, the solar cell can be attract fast and cheap in a roll-to-roll process and in almost any desired specifications – up to several kilometers a long time single solar cell modules of men and women manufactured. However , the energy harvesting productivity of this type of solar cell is not going to very high. To increase the efficiency, a meaningful DTU team around Frederik J. Krebs stacked two such pv cells onto each other. Each of these absorbs another type of part of the solar spectrum, so that the which results tandem polymer solar cell transforms more of the incoming sunlight into electricty.
But the multilayer coating presents a great many new challenges, as Andreasen – the best way: “Lab studies have shown that by now coated layers may be dissolved since solvent from the following layer, inflicting on complete failure of the solar cellular phone. ” To prevent redissolution of the very first solar cell, the scientists offered a carefully composed protective second time beginners coating between the two solar cells. The entire protective coating contains a layer made with zinc oxide (ZnO) that is make certain to 40 nanometres thick – with regards to a thousand times thinner than a a persons hair.
To check shape and function of an protective coating and the other sheets of the tandem solar cell, the main scientists used the exceptionally sharp Xray vision of DESY’s research source of light PETRA III that can reveal premier details. “The solar cell file format is very delicate, consisting of twelve personal layers altogether. Imaging the complete file format is challenging, ” explained co-author Juliane Reinhardt from DESY’s treatment plan station P06 where the investigations were created. “And the sample was make certain to two by four microns bigger. “
Still, with the brilliant Xray beam from PETRA III, the main researchers could peer into the finish structure in fine detail, using a plan called 3D ptychography. This method reconstructs the three-dimensional shape and hormones of a sample from the way it then diffracts the incoming X-rays. A lot full 3D reconstruction a great number of overlapping X-ray diffraction images have to be noted down from all sides and angles. The benefit of ptychography is that it yields a higher pixel size than would be possible with standard X-ray imaging alone. And in distinction to electron microscopy, X-ray ptychography can also look deep inside the tune.
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“With 3D ptychography, we were able to image the complete roll-to-roll coated tandem solar cell, having, among other things, the integrity of the because it nanometres thin zinc oxide finish in the protective coating that easily preserved underlying layers from admission damage, ” said DESY researcher Gerald Falkenberg, head of the treatment plan station P06. “These are the 3 D ptychography measurements with the highest space resolution we have achieved so far. The advantages show that with the correct method of the intermediate layer, the underlying empedrar cell is protected from redissolution. “
The investigation paves how you can a possible industrial application of the new plan. “In a complex multilayer device as being a polymer tandem solar cell, ipod may fail in multiple expedited new usa passport, ” Andreasen pointed out. “What i was able to see with 3D ptychography was that the preparation of the espèce electrode combines the good conductivity the coarsely structured silver electrode applying good film forming ability the conducting polymer that infiltrates the main silver electrode and forms an easy surface for the coating of the more layers. ” This is what allows the main coating of very thin sheets, at very high speeds, still growing contiguous layers, without pinholes.
Exploring the complete structure can also provide valuable statistics for a possible optimization of the as well as the production process. “In principle i make the devices without knowing what the interior fridge freezer structure looks like in detail. But the actual structure tells us which parameters i can also modify, and which factors are essential for the device architecture, for example the special type of oral appliance of substrate electrode, and the method of the intermediate layer, ” Andreasen explained. “We were now that could verify that we can coat continuous, homogeneous layers, roll-to-roll from admission, at speeds up to several meters for each minute. We have shown that roll-to-roll work of tandem solar cells is possible, that will happen layers roll-coated from solution, knowing that it is only possible using a specific method of the intermediate layer between the pair of sub-cells. “
The resulting polymer bicicleta solar cell converts 2 . 67 per cent of the incoming sunlight to form electric energy, which is way below the productivity of conventional solar cells. “The productivity is low, compared to conventional pv cells, by a factor of 7 to 8, despite the fact that one should consider that the production the price of this type of solar cell is a great many orders of magnitude lower than to receive conventional solar cells. This is the particular a look at polymer solar cells, ” explained Andreasen. “Furthermore, this is the first example of a meaningful roll-to-roll coated tandem solar cellular phone where the efficiency of the tandem home gym actually exceeds that of the individual sub-cell devices by themselves. “
PETRA 3 produces extremely brilliant X-rays driving fast electrons from a powerful compound accelerator. The particles are expanded to nearly the speed of light because send down a magnetic skid?kning course. In each bend, the main electrons emit tiny X-ray whizzes that add up to a narrow and very bright X-ray beam.