Enhanced Power Conversion Efficiency Using a Ce³⁺:SrF₂ Down-Shifting Nanophosphor-Based Photoelectrode for Dye-Sensitized Solar Cell Applications

Abstract

A lanthanide-doped inorganic down-shifting nanophosphor that converts the intense ultra-violet (UV) light photons to visible-light photons is highly attractive for dye-sensitized solar cells (DSSCs) to enhance light harvesting and power conversion efficiencies. In the present research, for the first time, a highly luminescent Ce3+-doped SrF2 (Ce3+:SrF2) nanophosphor is employed as a down-shifting nanophosphor material in the photoanode of DSSC. The nanophosphor was synthesized by co-precipitation technique, followed by a rapid microwave calcination approach. The structural and morphological properties of the synthesized nanophosphor are investigated by X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, and transmission electron microscopy analyses. The optical absorption and emission characteristics of the Ce3+:SrF2 down-shifting nanophosphor are investigated. Interestingly, the nanophosphor displayed a broad luminescence in the visible region under UV wavelength excitation. Absorption studies show that the Ce3+:SrF2 nanophosphor absorbs the deep-UV and near-UV radiations, protecting the iodide electrolyte from thermal degradation. To further study the performance of the down-shifting layer in DSSC, the Ce3+:SrF2/TiO2 nanocomposite-based photoanodes were used to fabricate the DSSCs. As a result, the nanocomposite-based device has demonstrated an excellent photo-conversion efficiency of 8.8%. The improvement in the incident-photon-to-current efficiency curve and electrochemical values (J sc = 15.2 mA cm–2, V oc = 0.82 V, and FF = 0.73) are due to the enhanced visible-light photon harvesting and high chemical stability.

A Review on the Applicability of Luminescent Phosphors and Effective Positioning in Dye‐Sensitized Solar Cells for Enhanced Performance and Stability

“…Reproduced with permission. [39] Copyright 2021, American Chemical Society. (654-679 nm) energy level transitions, respectively.…”

“…d) J-V curves of the DSSCs with Ce 3þ :SrF 2 /TiO 2 DC composite-based photoanodes. Reproduced with permission [39]. Copyright 2021, American Chemical Society.…”

Feasibility of Emission-Enhanced CsPbCl3 Quantum Dots Co-Doped with Mn2+ and Er3+ as Luminescent Downshifting Layers in Crystalline Silicon Solar Modules

“…At the same time, it should have good luminescence properties, including a sufficiently large Stokes shift and a high emission quantum efficiency. Suitable candidates include organic dyes, , rare-earth-doped materials, − phosphorescent nanomaterials, , and inorganic quantum dots (QDs). − Inorganic perovskite (CsPbX 3 ; X = Cl, Br, I) QDs have become popular in research on luminescent nanomaterials because of their ease of preparation, adjustable E g values, and high photoluminescence quantum yields (PLQYs). − CsPbX 3 QDs are favorable candidates for LDS materials . However, CsPbX 3 QDs have two obvious shortcomings for use as LDS materials: their narrow-band edge emission leads to high reabsorption losses, and their poor stability is not conducive to long-term storage and use. − …”

Ni‐doped TiO 2 / TiO 2 homojunction photoanodes for efficient dye‐sensitized solar cells

“…3,4 To obtain high PCE performance, four requirements need to be simultaneously satisfied for DSSCs: (i) an extremely unadulterated sensitizer, 4 (ii) selection of sensitizer and electrolyte, 3-5 (iii) the eligibility between the lowest unoccupied molecular orbital of the sensitizer and the conduction band edge of photoanode material and (iv) the existence of a scattering layer. 6,7 However, there is still a major problem found in DSSCs originating from photoanode layer in terms of electron transport due to the presence of trap states in TiO 2 nanoparticles. 8,9 On the other hand, the incorporation of suitable dopants can effectively suppress the trap states and results in a higher PCE performance.…”

“…In the last three decades, dye‐sensitized solar cells (DSSCs) (with key components: a porous layer of TiO 2 nanoparticles covered with a molecular dye that absorbs sunlight, a counter electrode, which is a platinum‐based catalyst and an electrolyte solution that provides an environment for transport of electrons) have been widely researched owing to their numerous superior electrical and optical properties, such as strong resistance to oxygen, moisture and solar irradiance, 1 sufficient transparency 2 for bifacial applications and having a high power conversion efficiency (PCE) performance under low irradiance 3,4 . To obtain high PCE performance, four requirements need to be simultaneously satisfied for DSSCs: (i) an extremely unadulterated sensitizer, 4 (ii) selection of sensitizer and electrolyte, 3‐5 (iii) the eligibility between the lowest unoccupied molecular orbital of the sensitizer and the conduction band edge of photoanode material and (iv) the existence of a scattering layer 6,7 . However, there is still a major problem found in DSSCs originating from photoanode layer in terms of electron transport due to the presence of trap states in TiO 2 nanoparticles 8,9 .…”