Fabrication of Cost-Effective Dye-Sensitized Solar Cells Using Sheet-Like CoS2 Films and Phthaloylchitosan-Based Gel-Polymer Electrolyte

Platinum-free counter electrodes (CE) were developed for use in efficient and cost-effective energy conversion devices, such as dye-sensitized solar cells (DSSCs). Electrochemical deposition of CoS2 on fluorine-doped tin oxide (FTO) formed a hierarchical sheet-like structured CoS2 thin film. This film was engaged as a cost-effective platinum-free and high-efficiency CE for DSSCs. High stability was achieved using a phthaloychitosan-based gel-polymer electrolyte as the redox electrolyte. The electrocatalytic performance of the sheet-like CoS2 film was analyzed by electrochemical impedance spectroscopy and cyclic voltammetry. The film displayed improved electrocatalytic behavior that can be credited to a low charge-transfer resistance at the CE/electrolyte boundary and improved exchange between triiodide and iodide ions. The fabricated DSSCs with a phthaloychitosan-based gel-polymer electrolyte and sheet-like CoS2 CE had a power conversion efficiency (PCE, η) of 7.29% with a fill factor (FF) of 0.64, Jsc of 17.51 mA/cm2, and a Voc of 0.65 V, which was analogous to that of Pt CE (η = 7.82%). The high PCE of the sheet-like CoS2 CE arises from the enhanced FF and Jsc, which can be attributed to the abundant active electrocatalytic sites and enhanced interfacial charge-transfer by the well-organized surface structure

Prevalence of traumatic dental injuries to the anterior teeth among three to thirteen-year-old school children of Tamilnadu

Context: Dental trauma has become an important attribute of dental public health. The primary requisite before actively dealing with such problems is to describe the extent, distribution, and associated variables with the specific condition. Aims: The aim of the present study was to assess the prevalence and distribution of traumatic dental injuries (TDI) to anterior teeth among 3 to 13 years old Chidambaram school children. Settings and Design : A cross-sectional study was conducted. Data was collected through a survey form and clinical examination. Materials and Methods: A total of 3200 school children in the age group of 3-13 years were selected from 10 schools of Chidambaram, Tamilnadu. Information concerning sex, age, cause of trauma, number of injured teeth, type of the teeth, lip competence, terminal plane relationship and the molar relationship were recorded. Statistical Analysis Used: The statistical software EPIINFO (Version 6.0) was used for statistical analysis. In the present study, P≤0.05 was considered as the level of significance. Results: The trauma prevalence in the present study was 10.13%. Children with class I type 2 and mesial step molar relationship exhibited more number of dental injuries. Enamel fracture was the most common injury recorded. Only 3.37% of the children had undergone treatment. Conclusion: The high level of dental trauma and low percentage of children with trauma seeking treatment stresses the need for increased awareness in Chidambaram population

Comparative evaluation of audio and audio - tactile methods to improve oral hygiene status of visually impaired school children

Background: Visually impaired children are unable to maintain good oral hygiene, as their tactile abilities are often underdeveloped owing to their visual disturbances. Conventional brushing techniques are often poorly comprehended by these children and hence, it was decided to evaluate the effectiveness of audio and audio-tactile methods in improving the oral hygiene of these children. Objective: To evaluate and compare the effectiveness of audio and audio-tactile methods in improving oral hygiene status of visually impaired school children. Materials and Methods: In this study, the total study group comprised 48 visually impaired children that were randomly divided into two groups, with one group receiving the audio method and the other group receiving the audio-tactile method. Periodic reinforcement of health education was performed at an interval of 2 months. Re-examination was carried out after 2 months of health education to assess plaque scores. Data were statistically analyzed using paired t-test. Results: There was reduction in plaque scores in audio-tactile group after health education. In the audio-tactile group, the mean plaque scores of pre- and post-health education were 1.28 and 0.95, respectively. The difference was statistically significant (P < 0.001). In audio group, the mean plaque scores of pre- and post-health education were 1.15 and 0.14, respectively. The difference was statistically nonsignificant (P < 0.07). Conclusion: Visually impaired children could maintain an acceptable level of oral hygiene when taught using special customized methods. However, reinforcement at regular intervals is required for the maintenance of oral hygiene

Sputter-Deposited Binder-Free Nanopyramidal Cr/γ-Mo2N TFEs for High-Performance Supercapacitors

Abstract Due to their outstanding power density, long cycle life and low cost, supercapacitors have gained much interest. As for supercapacitor electrodes, molybdenum nitrides show promising potential. Molybdenum nitrides, however, are mainly prepared as nanopowders via a chemical route and require binders for the manufacture of electrodes. Such electrodes can impair the performance of supercapacitors. Herein, binder-free chromium (Cr)-doped molybdenum nitride (Mo2N) TFEs having different Cr concentrations are prepared via a reactive co-sputtering technique. The Cr-doped Mo2N films prepared have a cubic phase structure of γ-Mo2N with a minor shift in the (111) plane. While un-doped Mo2N films exhibit a spherical morphology, Cr-doped Mo2N films demonstrate a clear pyramid-like surface morphology. The developed Cr-doped Mo2N films contain 0–7.9 at.% of Cr in Mo2N lattice. A supercapacitor using a Cr-doped Mo2N electrode having the highest concentration of Cr reveals maximum areal capacity of 2780 mC/cm2, which is much higher than that of an un-doped Mo2N electrode (110 mC/cm2). Furthermore, the Cr-doped Mo2N electrode demonstrates excellent cycling stability, achieving ~ 94.6% capacity retention for about 2000 cycles. The reactive co-sputtering proves to be a suitable technique for fabrication of binder-free TFEs for high-performance energy storage device applications. Graphical Abstrac