Bi2Mo3O12:Eu3+/CaF2 bilayer film for UV down-shifting and antireflection in photovoltaic module

In this study, a novel fabrication method for a bilayer film consisting of the Bi 2 Mo 3 O 12 :Eu 3+ and CaF 2 was developed. Bi 2 Mo 3 O 12 :Eu 3+ film was prepared using the chemical solution method, eliminating the need for separate phosphor preparation. The excitation spectra of Bi 2 Mo 3 O 12 :Eu 3+ displayed a broad band within the range of 300 and 420 nm. Under ultraviolet (UV) excitation, the material emitted strong red luminescence, with a dominant peak around 615 nm, which coincides with the absorption range of silicon solar cells. Additionally, a CaF 2 anti-reflection layer was introduced to enhance optical transmittance. The average transmittance of the Bi 2 Mo 3 O 12 :Eu 3+ @CaF 2 bilayer film reached 92.3%, representing a 0.7% increase compared to the bare glass substrate (91.6%). As a proof-of-concept, applying Bi 2 Mo 3 O 12 :Eu 3+ @CaF 2 to this bilayer film on photovoltaic modules resulted in an absolute enhancement of 0.19% in power conversion efficiency.