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[Eu(3DPIQC)3] (where DPIQC = 3-(diphenyl phosphoryl)-1-isoquinolinecarboxylate), a luminescent europium complex with antenna ligands, has been carefully embedded within a polyvinyl butyral (PVB) matrix and the resulting material was used to prepare films used as luminescent down-shifting layers (LDSLs) for crystalline Si-based solar cells. The films were characterized using photoluminescence spectroscopy, atomic force spectroscopy (AFM), UV-Vis spectroscopy, and fluorescence microscopy. The AFM analysis shows films with low surface roughness, while fluorescence microscopy revealed that the Eu complex embedded in PVB assumed a spheroidal configuration, a morphology especially beneficial for optical applications. The so-obtained LDSLs were utilized as energy converters in c-Si solar cells to enhance the utilization of high-energy photons, thereby improving their overall efficiency. The determination of photovoltaic parameters carried out before and after the deposition of the LDSLs on the c-Si cells confirms a positive effect on the efficiency of the cell. The Jsc increases from 121.6 mA/cm2 to 124.9 mA/cm2, and the open circuit voltage (Voc) is found to be unrelated to the complex concentration in the films. The fill factor (FF) remains constant with the Eu concentration. The EQE curves indicate an enhancement in the performance of the photovoltaic cells within the UV region of the spectrum for all coated devices. Electrochemical impedance spectroscopy (EIS) was also carried out in order to analyze the effect of the Eu complex in the charge transfer process of the devices. [ABSTRACT FROM AUTHOR]

Building-integrated photovoltaics (BIPVs) are gaining recognition in urban settings for overcoming spatial constraints and enabling photovoltaic (PV) power generation. However, the dark appearance of traditional PV modules often hinders aesthetic integration and market adoption. To address this issue, research has focused on colored photovoltaic modules (CPMs) using a luminescent down-shifting layer (LDS) with high color purity and a broad color range. Despite advancements, most previous studies have focused on experimental implications, while the theoretical efficiency limits of LDS-based CPMs remain underexplored. The present manuscript aims to bridge this gap by elucidating the correlation between the optical characteristics of LDS-based CPMs and their desired color attributes, utilizing the Natural Color System (NCS) and CIELAB color space to rigorously explore the influence of color characteristics perceived by human observers. Furthermore, this study conducts a comprehensive evaluation of CPM performance across various module types, offering new insights into the field of BIPVs and providing valuable perspectives for their efficient and aesthetic integration into urban landscapes. [Display omitted] • Colored photovoltaic modules with a luminescent down-shifting layer present promising solutions for building-integrated photovoltaics. • This study examines the influence of photovoltaic module types on the performance and coloration of CPMs featuring an LDS. • Optimal performance is associated with a broad internal quantum efficiency spectrum extending beyond 1100 nm and with lower values below 350 nm. • Evaluation using the Natural Color System highlights hues such as Y and R80B as less efficient due to the broad photoluminescent emission of an LDS. • The efficiency of CPMs notably declines with higher CIELAB L ∗ values, emphasizing the importance of adjusting colors with L ∗ <60. [ABSTRACT FROM AUTHOR]