RESUMO
In dye-sensitized solar cells (DSSCs), the counter electrode (CE) plays a crucial role as an electron transfer agent and regenerator of the redox couple. Unlike conventional CEs that are generally made of glass-based substrates (e.g., FTO/glass), polymer substrates appear to be emerging candidates, owing to their intrinsic properties of lightweight, high durability, and low cost. Despite great promise, current manufacturing methods of CEs on polymeric substrates suffer from serious limitations, including low conductivity, scalability, process complexity, and the need for dedicated vacuum equipment. In the present study, we employ and evaluate a fully additive manufacturing route that can enable the fabrication of CEs for DSSCs in a high-throughput and eco-friendly manner with improved performance. The proposed approach sequentially comprises: (1) material extrusion 3-D printing of polymer substrate; (2) conductive surface metallization through cold spray particle deposition; and (3) over-coating of a thin-layer catalyzer with a graphite pencil. The fabricated electrodes are characterized in terms of microstructure, electrical conductivity, and photo-conversion efficiency. Owing to its promising electrical conductivity (8.5 × 104 S·m-1) and micro-rough surface structure (Ra ≈ 6.32 µm), the DSSCs with the additively manufactured CEs led to ≈2.5-times-higher photo-conversion efficiency than that of traditional CEs made of FTO/glass. The results of the study suggest that the proposed additive manufacturing approach can advance the field of DSSCs by addressing the limitations of conventional CE manufacturing platforms.
RESUMO
In many low income developing countries, socioeconomic, environmental and demographic factors have been linked to around half of the disease related deaths that occur each year. The aim of this study is to investigate the sociodemographic factors, mother and child health status, water, sanitation, and hygienic conditions of a Nepalese community residing in a hilly rural village, and to identify factors associated with mother and child health status and the occurrence of diarrheal and febrile disease. A community-based cross-sectional survey was carried out and 315 households from the village of Narjamandap were included in this study. Factors associated with diarrhea, febrile disease, and full maternal and under-five immunizations were assessed using logistic regression. Results showed that higher education level (middle school versus primary education; Odds Ratio (OR): 0.55, p = 0.04; high school versus primary education; OR 0.21, p = 0.001) and having a toilet facility at home were significantly associated with a lower risk of developing diarrhea and febrile disease (OR 0.49, p = 0.01), while, interestingly, the use of improved water supply was associated with higher risk (OR 3.07, p = 0.005). In terms of maternal immunization, the odds of receiving a tetanus toxoid vaccination were higher in women who had regular antenatal checkups (OR 12.9, p < 0.001), and in those who developed complications during pregnancy (OR 4.54, p = 0.04); for under-five immunization, the odds of receiving full vaccination were higher among children from households that reported diarrhea (OR 2.76, p < 0.001). The findings of this study indicated that gaps still exist in the mother and child healthcare being provided, in terms of receiving antenatal checkups and basic immunizations, as evidenced by irregular antenatal checkups, incomplete and zero vaccination cases, and higher under-five deaths. Specific public health interventions to promote maternal health and the health of under-five children are suggested.
