The Design and Optimization of an Anti-Reflection Coating and an Intermediate Reflective Layer to Enhance Tandem Solar Cell Photons Capture

Photonic Crystal Structures for Photovoltaic Applications

Photonic crystals are artificial structures with a spatial periodicity of dielectric permittivity on the wavelength scale. This feature results in a spectral region over which no light can propagate within such a material, known as the photonic band gap (PBG). It leads to a unique interaction between light and matter. A photonic crystal can redirect, concentrate, or even trap incident light. Different materials (dielectrics, semiconductors, metals, polymers, etc.) and 1D, 2D, and 3D architectures (layers, inverse opal, woodpile, etc.) of photonic crystals enable great flexibility in designing the optical response of the material. This opens an extensive range of applications, including photovoltaics. Photonic crystals can be used as anti-reflective and light-trapping surfaces, back reflectors, spectrum splitters, absorption enhancers, radiation coolers, or electron transport layers. This paper presents an overview of the developments and trends in designing photonic structures for different photovoltaic applications.

Exploring Ln(III)-Ion-Based Luminescent Species as Down-Shifters for Photovoltaic Solar Cells

In this work, we have compiled our research on lanthanide-based luminescent materials for use as down-shifter layers in photovoltaic (PV) mini-modules. The complexes we have prepared (C1-17), with formulas [Eu₂(phen)₂(bz)₆] (C1), [Eu₂(bphen)₂(bz)₆] (C2), [Eu(tta)₃bphen] (C3), [Eu(bta)₃pyz-phen] (C4), [Eu(tta)₃pyz-phen] (C5), [Eu(bta)₃me-phen] (C6), [Er(bta)₃me-phen] (C7), [Yb(bta)₃me-phen] (C8), [Gd(bta)₃me-phen] (C9), [Yb(bta)₃pyz-phen] (C10), [Er(tta)₃pyz-phen] (C11), [Eu₂(bz)₄(tta)₂(phen)₂] (C12), [Gd₂(bz)₄(tta)₂(phen)₂] (C13), [EuTb(bz)₄(tta)₂(phen)₂] (C14), [EuGd(bz)₄(tta)₂(phen)₂] (C15), [Eu_1.2Gd_0.8(bz)₄(tta)₂(phen)₂] (C16), and [Eu_1.6Gd_0.4(bz)₄(tta)₂(phen)₂] (C17), can be grouped into three families based on their composition: Complexes C1-6 were synthesized using Eu³⁺ ions and phenanthroline derivatives as the neutral ligands and fluorinated β-diketonates as the anionic ligands. Complexes C7-11 were prepared with ligands similar to those of complexes C1-6 but were synthesized with Er³⁺, Yb³⁺, or Gd³⁺ ions. Complexes C12-17 have the general formula [M1M2(bz)₄(tta)₂(phen)₂], where M1 and M2 can be Eu³⁺, Gd³⁺, or Tb³⁺ ions, and the ligands were benzoate (bz^-), 2-thenoyltrifluoroacetone (tta^-), and 1,10-phenanthroline (phen). Most of the complexes were characterized using X-ray techniques, and their photoluminescent properties were studied. We then assessed the impact of complexes in the C1-6 and C12-17 series on the EQE of PV mini-modules and examined the durability of one of the complexes (C6) in a climate chamber when embedded in PMMA and EVA films. This study emphasizes the methodology employed and the key findings, including enhanced mini-module efficiency. Additionally, we present promising results on the application of complex C6 in a bifacial solar cell.