Interlaboratory Comparison of Solar Cell Measurements Under Low Indoor Lighting Conditions

Abstract

In recent years, industrial demand for energy harvesting from the indoor environment using photovoltaic (PV) solar cells has grown substantially. Much of this demand is focused on powering Internet of Things devices such as remote sensors and actuators because their power requirements can be easily met by indoor PV cells that convert, otherwise, wasted indoor light energy into low power electricity. However, accurate measurement of PV cells’ indoor performance is challenging because there are currently no broad consensus approaches or standards for doing such measurements. Here, we have taken the first steps toward establishing such a consensus by performing an interlaboratory comparison (ILC) of measurements of a PV solar cell under three distinct low illumination reporting conditions. In this bilateral comparison, each laboratory uses a different technique for reporting the performance parameters of the cell under a fixed set of agreed upon illumination conditions. Our results demonstrate good agreements under some reporting conditions and divergent results under another. Yet, first steps have been taken toward understanding the challenges of establishing a universally acceptable method of measurement.