Very wide-bandgap undoped and Y 2 O 3-doped ZrO 2 nanoparticles were synthesized and their structural, optical, morphological and energy characteristics were investigated. It was found that the bandgap value in ZrO 2 decreases with Y 2 O 3 doping. The developed materials were used for fabrication of nanostructured photoelectrodes for perovskite solar cells (PSCs) with the architecture of glass/FTO/ZrO 2-Y 2 O 3 /CH 3 NH 3 PbI 3 /spiro-MeOTAD/Au. The power conversion efficiency in the PSCs based on ZrO 2-Y 2 O 3 photoelectrodes was significantly higher than that for undoped ZrO 2 photoelectrodes. We have found that nanostructured layers, based on very wide-bandgap materials could efficiently transfer the injected electrons via a hopping transport mechanism.

The improvement of dye‐sensitized solar cells (DSSCs) performance can be realized by using rare‐earth and Nb‐doped TiO2 mesoporous photoelectrodes. The undoped, Nb‐doped, and rare‐earth‐doped TiO2 mesoscopic layers were prepared using a sol–gel method followed by a hydrothermal treatment. The Nb content was varied from 0.7 to 2.7 mol.%. The samples of complex rare‐earth titanium oxides with fluorite‐like structure containing Nb were synthesized using mechanical activation method. A series of fluorite‐like Sm2[TixNb1–x]2O7 compounds with varied Nb content was synthesized. The structure and morphology of obtained materials were characterized using XRD, SEM, and optical absorption spectroscopy. The prepared TiO2 mesoscopic layers were used for fabrication DSSCs. We have found that the photovoltaic parameters of DSSCs based on TiO2 sensitized with N719 dye, are closely related to the electronic structure of the Nb‐doped TiO2 electrodes. The changes of short circuit current of DSSCs were explained in relation to the electronic structure of the TiO2 electrodes. We have shown that the Nb doping enhances the junctions between neighboring nanoparticles and decreases the bulk electrical resistivity of the TiO2 electrodes. For the TiO2 electrodes doped with Nb the best DSSC performance with the energy conversion efficiency of 9.7% was obtained for Ti0.983Nb0.017O2 compound with 1.7 mol.% of Nb. Thus we have improved the device efficiency by 9% in comparison with the DSSC based on undoped TiO2 electrode. The developed rare‐earth doped compounds SmTiNbO were also used for fabrication and characterization of DSSCs. However, unlike Nb‐doped TiO2 layers, the efficiencies of DSSCs based on Nb‐doped complex rare‐earth titanium oxides were low in comparison with undoped TiO2.

Nb-doped TiO 2 nanoparticles with different doping concentrations, varied from 0 to 2.7 mol.%, were prepared by the sol-gel method followed by thermal treatment. The obtained nanoparticles were used to fabricate a series of electron transport layers for constructing perovskite solar cells (PSCs). The prepared layers were characterized using X-ray diffraction and optical transmission measurements. The effects of Nb doping concentration in TiO 2 layers on the optical absorption behavior, the morphology and charge carrier dynamics were studied. A series of PSCs, based on the developed electron transport layers was fabricated and examined. It was found that PSC fabricated with 2.7 mol.% Nb content TiO 2 electron transport layer have shown up to 19 % improvement of a power conversion efficiency compared to that, based on an undoped TiO 2 layer.

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