Photon Up-Conversion Strategies for Enhanced Solar Energy Conversion: Mechanism, Material and integrated Challenges

Highlights  Triple-triple Annihilation upconversion for enhanced visible-light harvesting  Lanthanide-doped UC materials for stable NIR-to-visible photon conversion  Hybrid organic-inorganic UC systems for photovoltaic and photocatalytic integration  Spectral management strategies to overcome solar cell absorption losses  Challenges in low solar-flux UC efficiency and device-level optical limitations.  Novel UC material engineering (plasmonic coupling, core-shell designs) to boost triplet energy transfer and overall upconversion efficiency