The CHEOPS Protocol: Performance Measurement and Stability Testing

Key Facts

  • Standardised protocol on irradiation, cell performance measurement, stability testing for encapsulated cells, sample requirements and measurement conditions
  • Norms for the communication of data
  • Protocol adopted unanimously by all major EU-funded research and innovation projects in the domain of perovskite photovoltaic research.


CHEOPS partners were the main driving force behind a new initiative to increase transparency of perovskite research, through the introduction of a unified standard for performance measurement and stability testing of perovskite-based photovoltaic devices. The recommendations for measurement and testing of perovskite-based PV devices are gathered in the CHEOPS protocol. It covers irradiation, cell performance measurement, stability testing for encapsulated cells, sample requirements, measurement conditions and data which partners need to communicate. For example the CHEOPS protocol specifies that stability testing for encapsulated cell samples needs to include testing at 85°C in the dark in inert atmosphere or air, exposure to thermal cycling between -40°C and 85°C for 200 cycles, to endure light soaking at 60°C for 1000 h at the maximum power point (MPP) if a suitable setup is available, a damp-heat test at 85% relative humidity and 85°C for 1000 h and lastly reverse bias cells during IV scans up to -2V.


With the introduction of mutually shared and EU-wide approaches to measurement of perovskite PV devices, a major barrier to advancing the technology had been overcome. The following projects have committed to follow the CHEOPS protocol for performance measurement and stability testing: APOLO, APPEL, CHEOPS, ESPResso, FASTEST, HYPERION, MEASTRO, No-LIMIT, PERTPV and POSITS.


Unifying measurements means changing the habitual practices of local research groups. Also within CHEOPS, that process was a lengthy yet worthwhile endeavor as CHEOPS eventually managed to convince all EU-funded research projects in the field of perovskite PV research to commit to this protocol for future research and innovation.

Scientific Output

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The CHEOPS protocol is currently being put into use in the follow-up projects that were created after the CHEOPS Project. Read more about the follow-up projects steaming from CHEOPS here.