The potential-induced degradation (PID) is one of the biggest quality and reliability issues for photovoltaic modules. PID mainly occurs  when solar modules are operated at high system voltages and in humid environments. Since the discovery of PID, manufacturers of solar cells and solar modules have developed a variety of measures to reduce PID susceptibility. Furthermore, by conducting in quality tests they have to continually ensure that their products have sufficient resistance to PID.

Researchers at Fraunhofer CSP were able to identify the physical principles of the defect mechanism and develop an easy-to-use PID testing method for silicon solar cells. The method is characterized in particular by the fact that it works without the cost-intensive production of complete solar modules and their testing in large, specially operated climate chambers. As a standardized test procedure on the basis of DIN SPEC 91348 it moreover ensures improved measurement and comparability of PID susceptibility.

Based on this PID testing method, the company Freiberg Instruments developed the test device PIDcon, which is already being successfully operated by many companies in the photovoltaic industry. In addition, the production of PIDcheck, a mobile device that can be used to determine the PID susceptibility of solar modules in the field, started in June 2018.


  • Solar cell PID test (according to SEMI-PV075-00-1016, DIN SPEC 91348)
  • Polymer encapsulant PID quality test (according to SEMI-PV075-00-1016)
  • Solar module PID Test (according to IEC 62804-1 TS)
  • On-site solar module PID testing, recovery tests (in field, without dismounting of modules)
  • PID benchmark tests and databases
  • Fabrication of PID free reference materials and devices
  • Development of measurement devices and technical support
  • Defect analysis using microstructural diagnostic methods
  • PID test on the back of bifacial solar cells
  • PID tests under simultaneous lighting to evaluate degradation in field operation

PID Testing Method for Solar Cells and Modules according to DIN SPEC 91348


PID Testing Devices