Interfacial photonic-electronic synergy in dielectric nanocomposite transport layers for high-efficiency perovskite photovoltaics

Planar perovskite solar cells face a fundamental compromise between optical management and electronic optimization in conventional electron transport layers (ETLs). Here, we propose an approach through dielectric engineering by embedding high dielectric constant (εr = 8.5) ZnO nanoparticles within SnO2 ETLs to create a bifunctional nanocomposite that simultaneously harnesses Mie resonance-enhanced light trapping and work function-tuned charge extraction. Finite-difference time-domain simulations reveal near-field intensity amplification at the ETL/perovskite interface. Ultraviolet photoelectron spectroscopy confirms a 0.31 eV reduction in the conduction band minimum. These findings synergistically boost photon harvesting and carrier injection. The optimized CH3NH3PbI3 devices achieve a power conversion efficiency of 21.1%, representing a 9.9% relative efficiency gain over SnO2-based controls (19.2%). This dielectric nanocomposite strategy establishes a viable framework for decoupling photonic and electronic optimization in solution-processed perovskite photovoltaics devices.