Investigation of NbO/SiO short-wave pass filters for beam-splitting application in a PV/CSP solar hybrid system.

Multilayer thin-film filters for beam-splitting applications were designed, fabricated, and characterized. Optimized 13- and 35-layer / filters on K9 substrates achieved wideband transmission in the range of [580-1100 nm]. Optical and structural characterizations were performed using spectrometry, atomic force microscopy (AFM), and X-ray diffraction (XRD). The //9 glass filter exhibited sensitivity to deposition conditions, especially in the very short wavelengths. Post-deposition annealing improved the filters' morphology and optical performance, particularly in short wavelengths. Both filters demonstrated efficient performance with average transmittance values of 87.56% and 83.72%, respectively. Additionally, the highest reflectance and average reflectance in the remaining range were measured as 62.42% and 98%, respectively, making them suitable for hybrid photovoltaic thermal systems under optimized deposition and annealing conditions.