Quantifying the influence of colors on the performance of c-Si photovoltaic devices
Publication from Materials
Gerhard Peharz, Andreas Ulm
Renewable Energy 129, Part A, Pages 299 - 308, 5/2018
Freedom in color design is regarded to be of high relevance for building integrated photovoltaics. Several solutions on individually colored solar cells and photovoltaic modules are available and/or are under development. Those colored photovoltaic products usually generate less power than reference devices which are optimized for maximum efficiency. Color and photovoltaic energy generation are both determined by fundamental optical effects such as reflection and absorption of light. In the current paper, fundamental physical calculations are conducted in order to quantify the impact of different colors on the power loss of photovoltaics. In particular monochromatic colors are investigated by generating pill box reflection spectra and an incident solar reference spectrum. The remaining solar intensity is considered to be converted in an ideal solar cell comprised of crystalline silicon. Moreover, power losses related to standardized colors defined in the classical RAL color set are investigated. Key findings of the results are that even highly saturated monochromatic colors can be realized at relatively low power losses of less than 7%. Standardized colors result in higher power losses. In particular, Blue, Green, dark Grey, Brown and Black correspond to half the power loss determined for Yellow, Orange, Red, Violet, bright Grey and White.