Tests conducted by the Helmholtz Zentrum Berlin (HZB) in Germany have shown that perovskite works solar cells that work at high wide-wide burden in Europe, suffer from higher performance losses in the winter compared to conventional PV devices. However, the scientists warned that this seasonal boundness at lower latitudes could be less pronounced.
A group of researchers from Helmholtz-Zentrum Berlin (HZB) in Germany has performed a 4-year outdoor test of standard perovskite solar cells in one of his facilities in Germany and has discovered that PVSKITE-based PV devices can suffer from higher seasonal solar cells.
The scientists said that testing was the longest ever performed on an external data set for Perovskite PV, for which the lack of a long track record remains one of the largest obstacles to its commercial maturity, since device still represents long-term stability instead of efficiency on both research and industrial levels.
Their measurements were performed on an open-air test field in Berlin with standard glass laminated perovskiet solar cells based on a substrate made of Indium Tia-Oxide (ITO), a 2PACZ layer, a perovskietbietabsorber with an energy band of 1.65 EV, a Elektrontransport layer (ETL) made from Buckminsterfullere (C60),),, a buffer layer of tinoxide (snox), and a copper (cu) metal contact.
“The devices shown are the most stable that we have checked outdoors; that is why this dataset is very suitable for discussing seasonal effects,” they explained, and noticed that the test facility is exposed to high irradiation and high temperatures in the summer, as well as low irradiation light and low temperatures in the winter.
At the end of the 4-year analyzed period, the Academicians found that the perovskiet cells offer a good “summer-to-summer” statement, with the devices losing minimum performance losses in the first two summers and less than 15% in the following summers. The devices, on the other hand, turned out to be 30% less efficient in the winter compared to the summer.
The researchers identified four factors that led to this difference in performance: changes in the spectral circumstances; the effect of the temperature coefficient; hysteresis in the current density -voltage (J–V) Features and the corresponding MPP tracking losses; And the so -called “metastability” of Perovskiet, which consists of all those processes that cause perovskiet breakdown.
Regarding the first factor – the seasonal changes in the solar spectrum – the group discovered that they can lead to a difference of 10% in generated current between summer and winter at the same radiation levels. “In comparison with Berlin, locations closer to the equator experience less pronounced seasonal spectral variation because of the impact of latitude on seasonal air mass variation,” they specified. “That is why the relatively high changes in generated electricity as a result of spectral shifts that are observed at our location would be reduced at more equatorial locations.”
Regarding the temperature changes, which usually depend on the location of a project, the researchers noted that their influence was largely related to the condition and age of the cells.
The analysis of metastability identified light acceleration as the most recurring problem.
“Light -collected losses at locations with high insulation and ambient temperatures throughout the year can be more than twice as low compared to locations with less favorable conditions,” the researchers noted. “In the perovskiet -sun cells studied, these losses are linked to the size of JV -Hysteresis, which increases considerably in outdated devices and at low operating temperatures. As a result, the energy breach of the observed devices is reduced during the third and fourth winters.”
The group concluded by saying that more accurate data is needed to understand the real size of the observed seasonal factor, although they also stated that the test offers promising results that demonstrates the potential of this technology to reach the operational lifetime requirements of current commercialized PV technologies.
Their findings are available in the study “Seasonalness in Perovskiet Solar cells: Insights from 4 years of outside data“Published in Advanced energy materials.
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