Development of novel orange colored photovoltaic modules with improved angular stability and high energy efficiency

This work illustrates a novel approach for the development of orange multilayer interference coatings with improved angular stability of color while maximizing energy efficiency. The high energy efficiency of these interference coatings is based on thin film interference phenomena, which is achieved by depositing multilayer coatings on the inner side of the glass substrate. These multilayer interference coatings are designed to selectively reflect a narrow spectral band of visible light while being transparent to the rest of the solar spectrum, ensuring minimal loss of module efficiency. In this work, three distinct simulated multilayer interference coatings, such as easy orange (EO), thin orange (TO) and enhanced secondary peak orange (ESPO) are deposited on flat and structured glass substrates, that exhibit high color saturation and low angular dependence. Irrespective of substrate type, all of these coatings exhibit high solar energy transmittance (τ_e) with an average relative light loss of only 12.1 % after multilayer deposition. Angle dependent reflectance measurements, supported by simulation data show that multilayer interference coatings deposited on structured glass substrates are more angular stable than coatings deposited on flat substrates, regardless of the coating type. For the proof of concept, these multilayer interferential coated structured glass substrates are laminated with mini photovoltaic (PV) modules. In addition, the relative efficiency loss of the colored PV module is found to be only ∼10 % for the ESPO coating on the structured glass substrate, indicating a high percentage of conserved solar energy of ∼90 %. Due to high conservation of energy and improved color stability, the developed orange PV module can significantly promote the architectural integration of solar systems in buildings.