Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

Thin film CIS PV module with improved performance and high long-term stability

At project start in 2001 Würth Solar has delivered to the project standard CIS modules (60cm x 120cm) with efficiencies above 8%. Meanwhile the modules have been further improved and Würth Solar demonstrated CIS average efficiencies above 10%. Second generation CIS modules with output power at STC of up to 79W have been tested in the second field-test phase.

The dc performance ratio relates the average efficiency of a module (defined as monthly sum of module output power divided by monthly solar irradiation on the module area) to the nominal STC efficiency (data sheet value given by the manufacturer). Most of the second-generation CIS modules have a DC performance ratio between 88% and up to 96%. The dependence of power on the operation temperature is similar to silicon; the power temperature coefficients are only marginally better than the silicon data. The performance under weak irradiance levels is also comparable to the low light performance of silicon PV modules. The main reason for the improved performance ratio is the characteristic increase of the module efficiency in the first weeks or even months after installation with a subsequent stabilisation of the module efficiency on a higher level.

No degradation has been observed for the second-generation modules since the installation in spring/summer 2003. Accelerated ageing experiments have been performed and delivered no indications for stability problems.

In the project, stability has been proven for a one-year period. This is still a minor part of the 20 years and more of expected lifetime. To date, we find no indication in the measurement results that a long lifetime with stable performance dates cannot be achieved.

In conclusion, the CIS thin film PV technologies have proven their maturity and are ready for an introduction to the market.

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Reinhold-Wuerth-Strasse 4