New accurate contactless temperature measurement for photovoltaic devices

A technician is testing film solar cells.

Collaboration between two EMPIR projects enables demonstration of new temperature measurement technique for PV devices

EMPIR project Hybrid metrology for thin films in energy applications (16ENG03 Hymet) is working to develop new capabilities to assess thin film performance to aid their deployment in novel energy applications such as thin film solar cells.

EMPIR project ‘Enhancing process efficiency through improved temperature measurement 2’ (17IND04, EMPRESS 2) is working to improve the accuracy of a range of thermometer types used in manufacturing, as well as undertaking validation of in-situ references standards for combustion flame temperature measurement.




Collaboration between these two EMPIR projects has enabled the demonstration of an innovative new temperature measurement technique for PV devices. The HyMET project has adapted knowledge on contactless temperature measurement generated by EMPRESS 2 to allow accurate characterisation of solar cells.

The innovation

NPL, a partner in both projects, has demonstrated for the first time accurate, contactless temperature measurements of a photovoltaic (PV) device within its glass/polymer/glass encapsulation, with an uncertainty of less than 1 ºC. The method is based on phosphor thermometry and can provide spatially-resolved temperature measurements through the encapsulation of a PV module. The results represent a significant advancement for the characterisation of temperature in encapsulated energy-harvesting devices. These can be used to quantify the quality of the manufacturing process as well as to identify local degradation.

The efficiency of solar photovoltaic PV devices strongly depends on the operating temperature, resulting in a direct impact on the energy yield of PV systems. Accurate operational temperature determination is therefore crucial for intelligent materials selection, PV product design and for validating modelling techniques of thermal and electrical behaviour of PV devices. In addition, accurate temperature measurements allow accurate energy rating of PV products so that energy generation yield of PV systems can be correctly assessed for different locations around the world. Having a better knowledge of the operational temperature also reduces risk for PV system investors and owners, as performance losses due to temperature effects can be better understood.

This research has been published in a paper entitled In situ contactless thermal characterisation and imaging of encapsulated photovoltaic devices using phosphor thermometry in one of the most prestigious solar energy peer-reviewed journals, Progress in Photovoltaics: Research and Applications. This paper is highlighted on the front cover of the journal.

This EMPIR project is co-funded by the European Union's Horizon 2020 research and innovation programme and the EMPIR Participating States.

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