EPFL scientists have for the first time lab-tested the performance of perovskite solar cells under realistic conditions.
The perovskite solar cells were tested for their stability and efficiency under both diurnal and seasonal variations simulated by the lab.
Though often touted as a highly efficient and low-cost alternative to silicon solar cells, perovskite solar cells suffer from one major problem: stability.
Operational stability is commonly assessed either by continuous illumination in the lab or by outdoor testing.
The first approach has the disadvantage of not accounting for real-world operation variations in irradiance and temperature because of day-night and season changes.
According to the scientists, diurnal and seasonal variations are important for perovskite solar cells because of their slow response times.
On the other hand, outdoor tests require the devices to be encapsulated in order to protect them against exposure from harsh weather conditions.
It should be noted that while encapsulation addresses parasitic failure mechanisms, it fails to assess the perovskite material itself.
Now Wolfgang Tress, an EPFL scientist at the lab of Anders Hagfeldt, along with colleagues at the lab of Michael Grätzel, has brought real-world conditions into the lab, to increase the performance of perovskite solar cells.
Using data from a weather station near Lausanne, they reproduced the real-world temperature and irradiance profiles from specific days during the course of the year.
Thanks to this approach, the scientists were able to quantify the energy yield of the devices under realistic conditions, bringing them closer to real-world applications.
According to the scientists, temperature and irradiance variations does not affect the performance of perovskite solar cells in any dramatic way.
And though the efficiency of the cells decreases slightly during the course of a day, it recovers during the night.
According to Tress, the study provides a further step towards the assessment of the performance and reliability of perovskite solar cells under realistic operation conditions.
Image and content: Wolfgang Tress/EPFL