Color tunability in green, red and infra-red upconversion emission in Tm3+/Yb3+/Ho3+ co-doped CeO2 with potential application for improvement of efficiency in solar cells

Carvalho, Luiz G.A.; Rocha, Leonardo A.; Buarque, Juliana M.M.; Gonçalves, Rogéria Rocha; Nascimento, Clébio S.; Schiavon, Marco A.; Ribeiro, Sidney J. L.; Ferrari, Jefferson Luis

doi:10.1016/j.jlumin.2014.11.027

Cited by 31 publications

(13 citation statements)

References 25 publications

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“…Ceria (CeO 2 ) has attracted extensive interest and demonstrated multifunctionality in many fields, such as catalytic applications [15][16][17] , solar cells and photoelectrochemistry [18][19][20] , lithium batteries 21,22 , fuel cells [23][24][25][26] and a variety of other energy-related applications 25,26 . The most important characteristic of ceria is the capacity to store and release oxygen via facile Ce 4+ /Ce 3+ redox cycles, which largely depends on the concentration and types of oxygen vacancies in the lattice as well as surface structures and states.…”

Section: Introductionmentioning

confidence: 99%

Fast ionic conduction in semiconductor CeO2-δ electrolyte fuel cells

et al. 2019

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Producing electrolytes with high ionic conductivity has been a critical challenge in the progressive development of solid oxide fuel cells (SOFCs) for practical applications. The conventional methodology uses the ion doping method to develop electrolyte materials, e.g., samarium-doped ceria (SDC) and yttrium-stabilized zirconia (YSZ), but challenges remain. In the present work, we introduce a logical design of non-stoichiometric CeO 2-δ based on non-doped ceria with a focus on the surface properties of the particles. The CeO 2−δ reached an ionic conductivity of 0.1 S/cm and was used as the electrolyte in a fuel cell, resulting in a remarkable power output of 660 mW/cm 2 at 550°C. Scanning transmission electron microscopy (STEM) combined with electron energy-loss spectroscopy (EELS) clearly clarified that a surface buried layer on the order of a few nanometers was composed of Ce 3+ on ceria particles to form a CeO 2−δ @CeO 2 core-shell heterostructure. The oxygen deficient layer on the surface provided ionic transport pathways. Simultaneously, band energy alignment is proposed to address the short circuiting issue. This work provides a simple and feasible methodology beyond common structural (bulk) doping to produce sufficient ionic conductivity. This work also demonstrates a new approach to progress from material fundamentals to an advanced lowtemperature SOFC technology.

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Section: Introductionmentioning

confidence: 99%

Fast ionic conduction in semiconductor CeO2-δ electrolyte fuel cells

et al. 2019

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“…where C t is the absorbance of methylene blue at time t, C o the initial absorbance, t the irradiation time, and k the kinetic constant. As discussed previously, the doping with Eu 3+ , Tb 3+ e Tm 3+ provided the formation of oxygen vacancies due to the differences in valence and ionic radius with Ce 4+ [22][23][24][25]. Oxygen vacancies act in a way to restrict the recombination of the e -/h + pairs, increasing the amount of ROS available and, consequently, the photocatalytic activity of the thin films [37].…”

Section: Resultsmentioning

confidence: 88%

“…The addition of Tb 3+ , which has an ionic radius of 0.92 Å, increases the crystallite due to the generation of oxygen vacancies [23]. The reduction in the crystallite size of CeO 2 when doped with Tm 3+ occurs because this ion has the same size of ionic radius and act on the surface of the crystal, hindering its growth [24]. Figs.…”

Section: Methodsmentioning

confidence: 99%

Study of obtaining thin films of CeO2 doped with 2 and 4 mol% of europium, terbium and thulium by spin coating: photocatalytic properties

Dias

2019

Cerâmica

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In this study, thin films of Eu3+, Tb3+ and Tm3+ doped CeO2 in the proportions of 2 and 4 mol% were obtained by spin coating and calcined at 700 °C. The films were characterized by XRD, SEM, AFM and UV-vis techniques. The photocatalytic activity of the thin films was measured by the degradation of the methylene blue (MB) dye. The thin films were submitted to 4 photocatalytic cycles to analyze the capacity to be reused. XRD patterns showed no secondary phase formation, where all characteristic peaks were related to CeO2. SEM micrographs indicated that doping at 4 mol% promoted the reduction in the thickness and surface porosity of the thin films. AFM images indicated the increase in surface roughness with rare earths doping. Doping with Eu3+, Tb3+ and Tm3+ increased the degradation of the methylene blue dye by at least 15% for thin films doped at 4 mol%. The reuse tests indicated that the photocatalytic activity remained practically constant even with the application of four consecutive cycles.

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“…However, considering that a large part of the solar radiation is ultraviolet (UV) and infrared (IR) light which is not able to promote the photoexcitation of the dye, the development of materials able to absorb energy at different wavelengths and emit in the visible region may promote an increase of the dye absorption. This strategy can change the useable wavelengths, utilizing more of the solar spectrum, thereby enhancing the efficiency of the solar cells [12][13][14].…”

Section: Introductionmentioning

confidence: 99%

SiO2-TiO2 doped with Er3+/Yb3+/Eu3+ photoluminescent material: A spectroscopy and structural study about potential application for improvement of the efficiency on solar cells

Buarque

Manzani

Scarpari

et al. 2018

Materials Research Bulletin

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The various synthesis conditions to obtain a material based on SiO 2-TiO 2 co-doped with Er 3+ /Yb 3+ /Eu 3+ were investigated, searching for those that present the greatest potential to improve the efficiency of solar cells. Conditions adjusted included heat-treatment temperatures, concentrations of matrix, and concentrations of dopants. Raman spectroscopy results demonstrated the effect of the annealing temperatures on the TiO 2 phase transition and the crystalline phase of the materials, which interfere with the photoluminescence of the materials. The band gap of the materials was evaluated by diffuse reflectance and it decreased due to the doping. The materials were able to absorb UV and IR energy and emit in the visible region, verified by the down conversion, up conversion and the double excitation of the materials. The results showed that the materials may be used as a strategy to use a greater portion of the solar spectrum, improving solar cell efficiency.

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Color tunability in green, red and infra-red upconversion emission in Tm3+/Yb3+/Ho3+ co-doped CeO2 with potential application for improvement of efficiency in solar cells

Cited by 31 publications

References 25 publications

Fast ionic conduction in semiconductor CeO2-δ electrolyte fuel cells

Fast ionic conduction in semiconductor CeO2-δ electrolyte fuel cells

Study of obtaining thin films of CeO2 doped with 2 and 4 mol% of europium, terbium and thulium by spin coating: photocatalytic properties

SiO2-TiO2 doped with Er3+/Yb3+/Eu3+ photoluminescent material: A spectroscopy and structural study about potential application for improvement of the efficiency on solar cells

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