In the present work, a relationship between the pencil-like growth of wurtzite zinc oxide (ZnO) with specific surfaces to support zinc sulfide (ZnS) deposition and its photovoltaic behavior is proposed. The wurtzite ZnO and zinc blende ZnS were explored in the context of the ZnO/ZnS interfaces obtained from zinc acetate (ZA) and zinc nitrate (ZN). A more effective ZnS coating was obtained on polar (101) ZnO surfaces, using ZN precursors, since the growth of planes is electronically and sterically favored because of the accentuated charge polarization. The hexagonal rod shaped ZnO with pencil-like end was examined by scanning electron microscopy, its surface stability was confirmed by density functional theory, and the shape change diagram obtained from the classic Wulff construction demonstrated that the (100) and (101) ZnO planes have increased energetic stability. From photovoltaic measurements we observed improvements in the ZnO/ZnS (ZN) (i) photocurrent density, from 0.88 to 1.03 mA cm⁻², corresponding to an increment of 17%; (ii) open-circuit photovoltage, from 0.62 to 0.67 V, equivalent to an increment of 8%; and (iii) photoconversion efficiency, from 0.40 to 0.42%, representing an improvement of 4.7% in the case of the predominant (101) plane growth. On the other hand all ZnO/ZnS systems have the same main absorption bandgap of 3.1 eV. Significantly, this data set demonstrates that better photovoltaic behavior can be achieved in ZnO/ZnS (ZN) through covering and surface growth control, resulting in adequate band alignment.

The growth of ZnS photoelectrodes on ZnO particles identified as ZnO/ZnS(ZC + TAA) by the microwave-assisted hydrothermal method showed excellent photovoltaic parameters of J_SC = 1.2 mA cm⁻² and FF = 0.66, even compared to ZnS(ZC + TAA) used as a reference sample with J_SC = 0.15 mA cm⁻² and FF = 0.52. A careful analysis indicates that the better charge transfer and the higher resistance to recombination present in the ZnO/ZnS(ZC + TAA) samples were the origin of the best photovoltaic behavior. These assertions are supported by a set of samples synthesized from different precursors resulting in different crystal structures, which can be directly associated with current densities and fill factors. All aspects about synthesis and optical/electronic parameters associated with structural features will be available in this article.

In this work, we present the potassium niobate (KNbO₃) nanoparticles as a suitable mesoporous photoelectrode for dye-sensitized solar cells (DSSCs).

This study proposes an alternative process for obtaining ZnO/ZnS:rGO heterostructures for use in DSSCs and as promising materials for potential applications in other photonic process, such as photocatalysis and photodetection. The compound was obtained through a microwave-assisted hydrothermal method, where the electromagnetic waves and temperature were crucial points for forming ZnO, ZnO/ZnS and reducing graphene oxide (GO). The XRD, Raman, FT-IR, and FESEM results presented the structural, morphological, and chemical structures, which suggest the conversion of ZnO to ZnS for samples with higher concentrations of reduced graphene oxide (rGO). Additionally, the optical properties were analyzed through photoluminescence and UV-Vis measurements. The electrical behavior of the photoelectrodes was investigated through J-V measurements in light and dark conditions. In addition, electrochemical impedance spectroscopy (EIS) was performed and Bode phase plots were created, analyzing the recombination processes and electron lifetime. The J-V results showed that for smaller amounts of rGO, the dye-sensitized solar cells (DSSC) efficiency improved compared to the ZnO/ZnS single structure. However, it was observed that with more significant amounts of rGO, the photocurrent value decreased due to the presence of charge-trapping centers. On the other hand, the best results were obtained for the ZnO/ZnS:1% rGO sample, which showed an increase of 14.2% in the DSSC efficiency compared to the pure ZnO/ZnS photoelectrode.

P25 hybridized with BaTiO ₃ + CaF ₂ + Dy showed a superior photovoltaic response when compared to pure P25 applied to DSSC cells, demonstrating potential application to solar energy conversion devices.