Effects of cobalt ion doped in the ZnS passivation layer on the TiO 2 photoanode in dye sensitized solar cells based on different counter electrodes

Afrooz, Malihe; Dehghani, Hossein; Khalili, Seyede Sara; Firoozi, Najmeh

doi:10.1016/j.synthmet.2017.02.012

Cited by 5 publications

(4 citation statements)

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“…For example, the addition of ZnS to a MgO film can result in the formation of smaller particles with a more uniform size distribution, as the ZnS can act as a nucleation site for MgO growth [19,20]. On the other hand, adding CdS can lead to the formation of larger particles due to the interaction between CdS and MgO during the deposition process, These changes in particle size can have significant implications for the properties and performance of the film, as demonstrated in previous studies [21,22,23]. The transmittance and reflectance of MgO films doped with CdS and ZnS can vary depending on the type and concentration of the dopant.…”

Section: Resultsmentioning

confidence: 68%

Effect of ZnS and CdS on Some Physical Properties of MgO Films

Hassan,

Albanda,

Al-Timimi

2023

East Eur. J. Phys.

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This article reports on the fabrication and characterization of MgO nanostructured films and the effect of ZnS and CdS on their structural, optical, and electrical properties. The MgO, MgO: ZnS, and MgO: CdS thin films were deposited using a Chemical spray pyrolysis technique onto glass substrates at 673 K. The XRD patterns revealed that the MgO thin films had a preferred (111) orientation with a pure cubic crystalline structure, while the ZnS and CdS layers had a hexagonal structure. The FE-SEM images showed that the MgO films had a nanostructured morphology with an average particle size of ~50 nm. The UV-Vis spectroscopy results showed that the addition of ZnS and CdS layers to the MgO films resulted in a shift in the absorption edge towards the visible region of the electromagnetic spectrum, indicating an improvement in their optical properties. These findings suggest that the MgOZnS and MgOCdS films could have potential applications in optoelectronic devices.

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Section: Resultsmentioning

confidence: 68%

Effect of ZnS and CdS on Some Physical Properties of MgO Films

Hassan,

Albanda,

Al-Timimi

2023

East Eur. J. Phys.

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“…Furthermore, the presence of massive injected electrons might promote the electrons to recombine with the oxidized dye molecules, in which the process usually happens in the range of micro-to milliseconds [1][2][3][4][5][6][7]. These recombination processes occur at the TiO 2 -dye-electrolyte interface with their probability determined by the kinetics recombination reaction.Several strategies were introduced to suppress the charge recombination process, for instance, the introduction of metal and/or non-metal element doping [8][9][10][11][12][13][14][15][16][17], as well as metal oxide coatings [18][19][20][21][22][23], as a passivation or blocking layer. The substitution of Ti 4+ with a different cationic dopant (typically metal-type dopant) modifies the conduction band, while replacing the O 2− with different anions affects the valence band of TiO 2 .…”

mentioning

confidence: 99%

“…Several strategies were introduced to suppress the charge recombination process, for instance, the introduction of metal and/or non-metal element doping [8][9][10][11][12][13][14][15][16][17], as well as metal oxide coatings [18][19][20][21][22][23], as a passivation or blocking layer. The substitution of Ti 4+ with a different cationic dopant (typically metal-type dopant) modifies the conduction band, while replacing the O 2− with different anions affects the valence band of TiO 2 .…”

mentioning

confidence: 99%

“…The plot for the test cell with the nanocrystalline TiO 2 layer exhibited a higher open-circuit voltage and a slower decay compared to that without, signifying a slower recombination process of conduction-band electrons with the oxidized species in the electrolyte. From the analysis, electron lifetime with respect to open-circuit voltage, τ n , was derived based on the decay curve normalized by the thermal voltage according to Equation (8).…”

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confidence: 99%

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Trap State and Charge Recombination in Nanocrystalline Passivized Conductive and Photoelectrode Interface of Dye-Sensitized Solar Cell

et al. 2020

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The dynamic competition between electron generation and recombination was found to be a bottleneck restricting the development of high-performance dye-sensitized solar cells (DSSCs). Introducing a passivation layer on the surface of the TiO 2 photoelectrode material plays a crucial role in separating the charge by preventing the recombination of photogenerated electrons with the oxidized species. This study aims to understand in detail the kinetics of the electron recombination process of a DSSC fabricated with a conductive substrate and photoelectrode film, both passivized with a layer of nanocrystalline TiO 2 . Interestingly, the coating, which acted as a passivation layer, suppressed the back-electron transfer and improved the overall performance of the integrated DSSC. The passivation layer reduced the exposed site of the fluorine-doped tin oxide (FTO)-electrolyte interface, thereby reducing the dark current phenomenon. In addition, the presence of the passivation layer reduced the rate of electron recombination related to the surface state recombination, as well as the trapping/de-trapping phenomenon. The photovoltaic properties of the nanocrystalline-coated DSSC, such as short-circuit current, open-circuit voltage, and fill factor, showed significant improvement compared to the un-coated photoelectrode film. The overall performance efficiency improved by about 22% compared to the un-coated photoelectrode-based DSSC.The mesoporous oxide photoelectrode material is the heart of a DSSC. It has responsibilities in anchoring the molecules of the dye sensitizer, and it acts as a medium for the transportation of electrons. In recent years, the development of binary and ternary oxide nanostructured photoelectrode materials such as titanium dioxide (TiO 2 ), zinc oxide (ZnO), tin oxide (SnO 2 ), and zinc tin oxide (Zn 2 SnO 4 ) attracted great attention due to their suitable conduction band and unique characteristics for DSC application. As of now, TiO 2 is the semiconductor of choice due to its promising properties such as wide bandgap energy, low cost, abundance, and non-toxic oxides. Moreover, the chemical inertness of TiO 2 makes it possible to allow the dye sensitizer molecule, which commonly has a carboxylate anchoring group, to be attached to the photoelectrode surface. Additionally, other distinguishing features of TiO 2 such as the high relative permittivity of anatase (~30-40) helps in lowering the electrostatic interaction between the injected electrons and oxidized dye molecules, thus reducing the possibilities of electron recombination [5]. Anatase (E g = 3.23 eV), rutile (E g = 3.05 eV), and brookite (E g = 3.26 eV) are three crystalline TiO 2 polymorphs that naturally exist. Brookite with an orthorhombic structure is difficult to synthesize in the laboratory compared to anatase and rutile. Even though rutile and anatase have the same tetragonal structure, a higher Fermi level of anatase by 0.1 eV compared to rutile makes it more desirable for DSSC application [6].When the photosensitized dye receives e...

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