Luminescent down-shifting layers based on an isoquinoline-Eu(<scp>iii</scp>) complex for enhanced efficiency of c-Si solar cells under extreme UV radiation conditions

The Atacama Desert's extreme UV radiation impacts photovoltaic devices, reducing silicon solar cell efficiency through overheating and photodegradation. To address this, we integrated a europium complex derived from 1-(diphenylphosphoryl)-3-isoquinolinecarboxylic acid into a polyvinyl butyral (PVB) matrix, forming a luminescent down-shifting layer (LDSL) that converts UV radiation into visible light. This LDSL improves light harvesting and mitigates UV-induced degradation. After LDSL application, photovoltaic analysis of a c-Si cell showed significant enhancements: short-circuit current density (<i>J</i> _sc) increased from 28.82 to 34.69 mA cm^-2, open-circuit voltage (<i>V</i> _oc) rose from 630.6 to 635.7 mV, and the fill factor (FF) remained stable. Incident photon-to-current efficiency (IPCE) curves indicated better performance, particularly in the UVA range, with overall cell efficiency improving from 14.10% to 16.62% at higher Eu complex concentrations. Electrochemical impedance spectroscopy (EIS) revealed that the Eu complex improved charge transfer, reducing recombination losses. This approach demonstrates significant potential for enhancing solar cell performance in high-irradiance environments like the Atacama Desert.