We present the properties and performance of fluorescent
waveguide
lattices as coatings for solar cells, designed to address the significant
mismatch between the solar cell’s spectral response range and
the solar spectrum. Using arrays of microscale visible light optical
beams transmitted through photoreactive polymer resins comprising
acrylate and silicone monomers and fluoresceino,o′-dimethacrylate comonomer, we photopolymerize well-structured
films with single and multiple waveguide lattices. The materials exhibited
bright green-yellow fluorescence emission through down-conversion
of blue-UV excitation and light redirection from the dye emission
and waveguide lattice structure. This enables the films to collect
a broader spectrum of light, spanning UV–vis–NIR over
an exceptionally wide angular range of ±70°. When employed
as encapsulant coatings on commercial silicon solar cells, the polymer
waveguide lattices exhibited significant enhancements in solar cell
current density. Below 400 nm, the primary mode of enhancement is
through down-conversion and light redirection from the dye emission
and collection by the waveguides. Above 400 nm, the primary modes
of enhancement were a combination of down-conversion, wide-angle light
collection, and light redirection from the dye emission and collection
by the waveguides. Waveguide lattices with higher dye concentrations
produced more well-defined structures better suited for current generation
in encapsulated solar cells. Under standard AM 1.5 G irradiation,
we observed nominal average current density increases of 0.7 and 1.87
mA/cm2for single waveguide lattices and two intersecting
lattices, respectively, across the full ±70° range and reveal
optimal dye concentrations and suitable lattice structures for solar
cell performance. Our findings demonstrate the significant potential
of incorporating down-converting fluorescent dyes in polymer waveguide
lattices for improving the current spectral and angular response of
solar cell technologies toward increasing clean energy in the energy
grid.