ISOS solar cell lifetime and stability testing
We can offer stability and lifetime tests of solar cells in accordance within ISOS procedures including dark testing (D), outdoor testing (O), laboratory weathering testing (L), and thermal cycling testing (T).DOI:10.1016/j.solmat.2011.01.036 Tests and price examples are listed in the table below.
|Temperature||Relative humidity||Light source||Duration||Estimated price|
|ISOS-D-1||Ambient||Ambient||-||1000 h||800 €a|
|ISOS-D-2||65 or 85 °C||Low||-||1000 h||1600 €a|
|ISOS-D-3b||65 or 85 °C||85 %||-||1000 h||3000 €a|
|ISOS-L-2||65 °C||Low||Simulated lightc||1000 h||1900 €a|
|ISOS-L-3||85 °C||50 %||Simulated lightc||1000 h||3000 €a|
|ISOS-O-2||Outdoor||Outdoor||Outdoord||1000 h / 1 year||900 €a / 3500 €a|
|ISOS-O-3||Outdoor||Outdoor||Outdoord||1000 h||1800 €a|
|ISOS T-3b||-40 to +85 °C||55 %||-||200 cycles||3000 €a|
bISOS-D-3 and ISOS-T-3 can only be carried out sequentially
cSimulated light source with spectrum close to AM1.5G
dFixed platform facing south with angle adjusted to latitude (Denmark) (solar tracking system can also be utilized at extra cost)
Several tests can be combined and modified according to specific needs. The test procedures include periodic IV characterization of samples, extraction of ageing curves for photovoltaic parameters, determination of T80 lifetime and detailed reporting of the data. Upon request advanced characterization techniques can be added to the testing routine, such as:
- LBIC – Periodic mapping of the active area using laser light for detecting gradual deterioration of the sample area
- IPCE – Periodic measurements for determining deterioration of charge generation properties
ISOS guidelines are testing procedures that were developed based on a consensus of the organic solar cells community during the International Summit on Organic Photovoltaics Stability (in 2010) and are commonly used for accurately determining the lifetime of the thin film solar cell technologies, such as polymer solar cells, DSSC, perovskite solar cells etc.DOI:10.1016/j.solmat.2011.01.036 Examples of baselines for the performance of polymer based solar cells under the different ISOS test conditions have been reported in literature.DOI:10.1016/j.solmat.2015.07.037
- Dark tests (ISOS-D-1, ISOS-D-2 and ISOS-D-3)
ISOS-D-1: Simple shelf life test where the samples are stored in room environment in dark and the IV curves are periodically recorded.
ISOS D-2: The samples are stored in an oven in dark at elevated temperature of 65 or 85 °C with the purpose of determining the thermal stability of the devices.
ISOS D-3: The samples are stored in a damp heat chamber with controlled temperature and relative humidity of 85 °C / 85%. The test is adopted from the IEC standards for solar cell qualification tests.
- Laboratory weathering (ISOS-L-2 and ISOS-L-3)
ISOS-L-2: The samples are exposed to indoor light exposure under a solar simulator with light intensity in the range of 0.7 to 1 sun and spectrum close to AM1.5G. The device temperature is controlled at 65 or 85 °C. The relative humidity is not controlled and is typically rather low. The test is aimed at revealing the photosensitivity of the sample.
ISOS-L-3: The samples are exposed to indoor light exposure in an environmental chamber with simultaneous exposure to light (intensity in the range of 0.7 to 1 sun and spectrum close to AM1.5G), elevated sample temperature of 85 °C and controlled relative humidity of 50%. This test is the harshest among the ISOS test, since the samples are exposed simultaneously to a multitude of environmental stress.
- Outdoor (ISOS-O-2 and ISOS-O-3)
ISOS-O-2 and ISOS-O-3: The samples are placed on a fixed platform facing south with angle adjusted to latitude (Denmark). The samples can be placed under passive load or left at open circuit conditions. In the case of ISOS-O-2 the samples are periodically taken inside and IV characterization is performed under a solar simulator for constructing the ageing curves. In the case of ISOS-O-3 the samples in addition to the indoor IV characterization are also frequently (every 15 minutes) measured outside while exposed to outdoor environment, which allows to record the change of the performance during the day and night and seasonal cycles. The outdoor tests are accompanied with full recording of the weather conditions (temperature, irradiation does, humidity, wind, precipitation etc.). The outdoor testing is the most real test that reveals the actual performance of the samples in outdoor conditions. The recommended duration of the test is at least 1 year in order to record the response of the sample to the full cycle of seasonal changes.
- Thermal cycling (ISOS-T-2)
ISOS-T-3: The samples are stored in a thermal chamber and subjected to cycles of temperature changes varying between -40 to +85 °C with relative humidity kept at 55% (where possible). The test is aimed at determining the sample sensitivity towards the temperature fluctuations in outdoor real conditions.