Does Spectral Down Conversion Live up to Its Promise in Perovskite Solar Cells?

Spectral down conversion presents a compelling strategy to boost perovskite solar cell (PSC) performance by shifting high-energy photons to wavelengths better aligned with the absorber. Its integration often enhances current density and power conversion efficiency; however, inconsistencies in external quantum efficiency reflect unresolved mechanistic complexities. This perspective examines luminescent conversion layer placement across PSC architectures, recommending modular glass-side configurations to optimize UV shielding and mitigate interface disturbance. To resolve experimental ambiguity, UV-selective JV methods and dim-light controls are proposed to decouple genuine spectral conversion contributions from extrinsic parasitic effects. The research community is encouraged to synergize photoluminescence quantum yield measurements with UV-enhanced EQE and spectral modeling for a comprehensive assessment of photon conversion pathways. Establishing standardized testing protocols will be instrumental in unlocking the promise of spectral down conversion as a scalable approach for next-generation, high-efficiency PSCs.