scholarly journals How Can the Introduction of Zr4+ Ions into TiO2 Nanomaterial Impact the DSSC Photoconversion Efficiency? A Comprehensive Theoretical and Experimental Consideration

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2955
Author(s):  
Aleksandra Bartkowiak ◽  
Oleksandr Korolevych ◽  
Gian Luca Chiarello ◽  
Malgorzata Makowska-Janusik ◽  
Maciej Zalas

A series of pure and doped TiO2 nanomaterials with different Zr4+ ions content have been synthesized by the simple sol-gel method. Both types of materials (nanopowders and nanofilms scratched off of the working electrode’s surface) have been characterized in detail by XRD, TEM, and Raman techniques. Inserting dopant ions into the TiO2 structure has resulted in inhibition of crystal growth and prevention of phase transformation. The role of Zr4+ ions in this process was explained by performing computer simulations. The three structures such as pure anatase, Zr-doped TiO2, and tetragonal ZrO2 have been investigated using density functional theory extended by Hubbard correction. The computational calculations correlate well with experimental results. Formation of defects and broadening of energy bandgap in defected Zr-doped materials have been confirmed. It turned out that the oxygen vacancies with substituting Zr4+ ions in TiO2 structure have a positive influence on the performance of dye-sensitized solar cells. The overall photoconversion efficiency enhancement up to 8.63% by introducing 3.7% Zr4+ ions into the TiO2 has been confirmed by I-V curves, EIS, and IPCE measurements. Such efficiency of DSSC utilizing the working electrode made by Zr4+ ions substituted into TiO2 material lattice has been for the first time reported.

2011 ◽  
Vol 64 (6) ◽  
pp. 820 ◽  
Author(s):  
Fuzhi Huang ◽  
Yi-Bing Cheng ◽  
Rachel A. Caruso

Porous aluminium doped TiO2 was prepared through a sol–gel process in the presence of a template. The doping enlarges the band-gap of the anatase TiO2, which modifies the TiO2 electrical properties. The porous Al/TiO2 films were assembled into dye-sensitized solar cells. A 45 mV enhancement of open-circuit photovoltage and 11% increase of fill factor at 2 wt-% doping concentration, and 8.6% improvement of the overall efficiency at 0.5 wt-% doping concentration were achieved relative to that of a cell containing non-doped TiO2 under the same conditions. This advance is attributed to the increase in conductivity with the Al-doping of the TiO2 electrode.


2019 ◽  
Vol 32 (2) ◽  
pp. 342-348
Author(s):  
M. Rekha ◽  
M. Kowsalya

Titanium dioxide nanoparticles have been synthesized by a novel modified sol-gel for the fabrication of natural dye sensitized solar cells. The natural photo sensitizer extracted from Cordia sebestena flower was mixed with the precursor solution. The flower dye has put the effort of a surfactant which has resulted colourized TiO2 instead of white TiO2. Whencompared to the conventional sol-gel method, this modified process has enhanced the properties of TiO2 like, morphology, uniformity in dye absorption. It has reduced the agglomeration of TiO2 and dye aggregation significantly. The optimized molecular geometry of sebestenoid D, the major pigment of Cordia sebestena and HOMO-LUMO plot are found using density functional theory. The TiO2 nanoparticles were subjected to structural, optical, spectral and morphological studies which showed improved properties in modified sol-gel process. Ecofriendly and low-cost natural dye sensitized solar cells (DSSC) were fabricated using conventional and pre-dye treated TiO2 sensitized by Cordia sebestena flower extract. The I-V studies showed the solar light photon to electron conversion efficiencies of 0.87 and 1.28 % for sol-gel and modified sol-gel methods, respectively. There has been an enhancement in efficiency by 47 % in modified sol-gel method which is very much promising in terms of efficiency for natural dye sensitized solar cells.


Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 296 ◽  
Author(s):  
Nikolai Tsvetkov ◽  
Liudmila Larina ◽  
Jeung Ku Kang ◽  
Oleg Shevaleevskiy

The performance of dye-sensitized solar cells (DSCs) critically depends on the efficiency of electron transport within the TiO2-dye-electrolyte interface. To improve the efficiency of the electron transfer the conventional structure of the working electrode (WE) based on TiO2 nanoparticles (NPs) was replaced with TiO2 nanotubes (NTs). Sol-gel method was used to prepare undoped and Nb-doped TiO2 NPs and TiO2 NTs. The crystallinity and morphology of the WEs were characterized using XRD, SEM and TEM techniques. XPS and PL measurements revealed a higher concentration of oxygen-related defects at the surface of NPs-based electrodes compared to that based on NTs. Replacement of the conventional NPs-based TiO2 WE with alternative led to a 15% increase in power conversion efficiency (PCE) of the DSCs. The effect is attributed to the more efficient transfer of charge carriers in the NTs-based electrodes due to lower defect concentration. The suggestion was confirmed experimentally by electrical impedance spectroscopy measurements when we observed the higher recombination resistance at the TiO2 NTs-electrolyte interface compared to that at the TiO2 NPs-electrolyte interface. Moreover, Nb-doping of the TiO2 structures yields an additional 14% PCE increase. The application of Nb-doped TiO2 NTs as photo-electrode enables the fabrication of a DSC with an efficiency of 8.1%, which is 35% higher than that of a cell using a TiO2 NPs. Finally, NTs-based DSCs have demonstrated a 65% increase in the PCE value, when light intensity was decreased from 1000 to 10 W/m2 making such kind device be promising alternative indoor PV applications when the intensity of incident light is low.


2021 ◽  
Author(s):  
Deepak Kumbhar ◽  
Sagar Delekar ◽  
Sarita Kumbhar ◽  
Ananta Dhodamani ◽  
Namdev Harale ◽  
...  

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3918
Author(s):  
Ratshilumela S. Dima ◽  
Lutendo Phuthu ◽  
Nnditshedzeni E. Maluta ◽  
Joseph K. Kirui ◽  
Rapela R. Maphanga

Titanium dioxide (TiO2) polymorphs have recently gained a lot of attention in dye-sensitized solar cells (DSSCs). The brookite polymorph, among other TiO2 polymorphs, is now becoming the focus of research in DSSC applications, despite the difficulties in obtaining it as a pure phase experimentally. The current theoretical study used different nonmetals (C, S and N) and (C-S, C-N and S-N) as dopants and co-dopants, respectively, to investigate the effects of mono-doping and co-doping on the electronic, structural, and optical structure properties of (210) TiO2 brookite surfaces, which is the most exposed surface of brookite. The results show that due to the narrowing of the band gap and the presence of impurity levels in the band gap, all mono-doped and co-doped TiO2 brookite (210) surfaces exhibit some redshift. In particular, the C-doped, and C-N co-doped TiO2 brookite (210) surfaces exhibit better absorption in the visible region of the electromagnetic spectrum in comparison to the pure, S-doped, N-doped, C-S co-doped and N-S co-doped TiO2 brookite (210) surfaces.


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