Improved light-harvesting and suppressed charge recombination by introduction of a nanograss-like SnO2 interlayer for efficient CdS quantum dot sensitized solar cells

g-C3N4@TiO2 photoanodes for high-efficiency QDSSCs: improved electron transfer and photochemical stability

In QDSSCs, a photoanode is an important part of connecting the external circuit, providing support for the transmission of photogenerated carriers to the external circuit, and also providing an attachment site for QDs. In this study, we prepared a g-C3N4@TiO2 composite for the photoanode by a two-step process. The results show that the use of g-C3N4@TiO2 greatly increases the specific surface area of the material, effectively inhibits the "electron-hole" recombination, and optimizes the stability and catalytic performance of the photoanode. Among them, the cell equipped with the g-C3N4@TiO2 photoanode has improved performance: Jsc = 26.5 mA cm-2, PCE = 8.2%, Voc = 0.62 eV, and FF = 0.50. Based on the research in this paper, it can be seen that the g-C3N4@TiO2 composite applied to the photoanode can effectively improve the cell performance and provide a feasible idea for optimizing QDSSCs.

Core-shell ZnO@TiO2 hexagonal prism heterogeneous structures as photoanodes for boosting the efficiency of quantum dot sensitized solar cells

In quantum dot sensitized solar cells (QDSSCs), the photoanode provides a stable support for the quantum dots, and promotes the production of photogenerated electrons and the transfer to external circuit. Therefore, it is very important to search for excellent photoanodes for the commercial application of QDSSCs. In this paper, a core-shell ZnO@TiO2 hexagonal prism heterogeneous structure was prepared by a two-step hydrothermal method. The ZnO@TiO2 heterogeneous structure not only has a unique 1D hexagonal prism morphology, but also can effectively inhibit the electron-hole recombination and has a greater light response and higher collection efficiency while speeding up the electron transmission rate. By adjusting the concentration of the TiO2 source, the best photoanode material Zn@Ti-2 was explored, and it showed excellent cell performance: Jsc = 25.4 mA cm-2, Voc = 0.71 V, PCE = 8.5%, and FF = 0.49. Compared with a single ZnO photoanode, the PCE value is increased by 25%. EIS, Tafel polarization and transient photocurrent responses confirm that the Zn@Ti-2 photoanode has higher catalytic activity and stability. Therefore, Zn@Ti-2 may be a promising photoanode material for QDSSCs.

ZnO–SnO2–Sn nanocomposite as photocatalyst in ultraviolet and visible light

By combining ZnO with SnO2, it is possible to obtain a photocatalyst with an extended lifetime and increased activity range in both ultraviolet and visible light. The paper presents the synthesis of ZnO–SnO2–Sn nanocomposite. The morphology and structure of the samples were characterized by XRD, FTIR, SEM–EDS and TEM–EDX analysis. The results showed that the synthesised nanocomposites consisted of hexagonal ZnO, cubic SnO2 and Sn nanoparticles. The results revealed that the highest removal efficiency (15.0%) of rhodamine B under visible light was achieved with ZnO–SnO2–Sn consisting of 10% of SnO2 and 5% of Sn, whereas the highest removal efficiency of methylene blue (95.6%) under UV light was achieved with ZnO–SnO2–Sn consisting of 10% of SnO2 and 1% of Sn. The presence of tin nanoparticles enhanced the photocatalytic properties directed towards visible light. The degradation of MB by ZnO–SnO2–Sn remained above 80% even in the 5th cycle, while under visible light during photodegradation the RB removal efficiency decreased from 20 to 14%.