Boosting Power Conversion Efficiency of Quantum Dot-Sensitized Solar Cells by Integrating Concentrating Photovoltaic Concept with Double Photoanodes

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.

Black TiO2-Based Dual Photoanodes Boost the Efficiency of Quantum Dot-Sensitized Solar Cells to 11.7

Quantum dot-sensitized solar cells (QDSSC) have been regarded as one of the most promising candidates for effective utilization of solar energy, but its power conversion efficiency (PCE) is still far from meeting expectations. One of the most important bottlenecks is the limited collection efficiency of photogenerated electrons in the photoanodes. Herein, we design QDSSCs with a dual-photoanode architecture, and assemble the dual photoanodes with black TiO2 nanoparticles (NPs), which were processed by a femtosecond laser in the filamentation regime, and common CdS/CdSe QD sensitizers. A maximum PCE of 11.7% with a short circuit current density of 50.3 mA/cm2 is unambiguously achieved. We reveal both experimentally and theoretically that the enhanced PCE is mainly attributed to the improved light harvesting of black TiO2 due to the black TiO2 shells formed on white TiO2 NPs.

Analysis of the chloride ion removal mechanism from simulated wastewater by discarded vitamin tablets

Vitamin (VM) tablets are often discarded or incinerated as medical waste, and untreated highly chlorinated wastewater is discharged, polluting the environment. In this study, Cu²⁺ was reduced by vitamin C (VC, a component of VM), and the precipitate formed by the reaction of its product with Cl^- in water was used to remove Cl^- from simulated wastewater. This allows for the resourceful use of waste VM, while also achieving the goal of dechlorinating wastewater. Meanwhile, the effect of various parameters on dechlorination was studied, and the dechlorination mechanism was analyzed. According to the results, the removal rate of Cl^- increased first and then decreased with pH, removal time and reaction temperature. Using VC in VM to dechlorinate simulated wastewater, the removal rate of Cl^- was 94.31% under optimum conditions: pH 2.5, temperature 30 °C and reaction time 10 minutes. According to the dechlorination process, it can be inferred that Cu²⁺ is reduced to Cu⁺ by VC, and Cu⁺ and Cl^- coprecipitate to remove Cl^-. Therefore, it is feasible to use discarded VM to treat high concentration chlorine-containing wastewater.