Phosphorescent Reflective Layers for Enhanced Light Harvesting in Semi-Transparent Solar Cells

This work explored the novel concept of applying translucent phosphorescent layers in a reflective configuration to passively enhance the efficiency of semi-transparent solar cells. Phosphorescent layers were fabricated by dispersing 50 wt.% of commercially available phosphors (LumiNova^® BG-300M or LumiNova^® GLL-300M) in a silicone host matrix and using a doctor blade coating technique to form uniform layers of 0.8 mm thickness. For a semi-transparent dye-sensitised solar cell (DSSC), the BG-300M and GLL-300M layers improved the DSSC’s efficiency by 15.39% and 13.13%, respectively. For a semi-transparent organic solar cell (OSC), the BG-300M and GLL-300M layers improved the OSC’s efficiency by 11.53% and 10.33%, respectively. These efficiency enhancements were on par with that achieved using a conventional opaque reflector (3M^TM Specular Film DF2000MA), highlighting the ability of the layers to function effectively as translucent back reflectors that could enhance device efficiency without compromising the device’s ability to transmit light. Thus, it was confirmed that phosphorescent reflective layers can effectively transform semi-transparent solar cells into more efficient translucent devices, finding potential applications in commercial windows to support the integration of renewable energy into sustainable buildings.