RESUMEN
The instability to moisture, heat, and ultraviolet (UV) light is the main problem in the application of quantum dot solar cells (QDSCs). Thin film encapsulation can effectively improve their operational stability. However, it is difficult to achieve multiple barrier effects with single layer of encapsulated film. Here, a hybrid thin-film encapsulation strategy is reported to encapsulate lead sulfide QDSCs, which can isolate moisture and partial thermal, and prevent the penetration of UV light, thus retarding the surface oxidation process of the quantum dots. After 60 h, the encapsulated device retains a normalized power conversion efficiency of 83.8% and 80.6% at 85% humidity and 75 °C, respectively, which is three and six times of the value obtained in unencapsulated devices. At continuous UV illumination, encapsulated device exhibits five times higher stability than the reference. This strategy provides the way for the overall improvement of the operating stability of lead sulfide QDSCs in harsh environments of high humidity, high temperature, and UV light.
RESUMEN
Water-droplet-based electricity generators are emerging hydrovoltaic technologies that harvest energy from water circulation through strong interactions between water and nanomaterials. However, such devices exhibit poor current performance owing to their unclear driving force (evaporation or infiltration) and undesirable reverse diffusion current. Herein, a water-droplet-based hydrovoltaic electricity generator induced by capillary infiltration with an asymmetric structure composed of a diode-like heterojunction formed by negatively and positively charged materials is fabricated. This device can generate current densities of 160 and 450 µA cm-2 at room temperature and 65 °C, respectively. The heterojunction achieves a rectification ratio of 12, which effectively suppresses the reverse current caused by concentration differences. This results in an improved charge accumulation of ≈60 mC cm-2 in 1000 s, which is three times the value observed in the control device. When the area of the device is increased to 6 cm2 , the current increases linearly to 1 mA, thus demonstrating the scale-up potential of the generator. It has been proven that the streaming potential originates from capillary infiltration, and the presence of ion rectification. The proposed method of constructing ion-diode-like structures provides a new strategy for improving generator performance.
RESUMEN
OBJECTIVES: To evaluate the reliability and validity of the Chinese version of pediatric voice handicap index (pVHI). MATERIAL AND METHODS: The original English version-pVHI was translated into Chinese. Parents of 52 children with voice dysphonia and 43 children with no history or symptoms of voice problems were asked to fill the Chinese pVHI questionnaires twice with an interval of 2 weeks. GRB (Grade, Roughness, Breathiness) scale was used for perceptual assessment by two otolaryngologists and one speech pathologist for each child's voice. The internal consistency was assessed using Cronbach's alpha coefficient. Pearson's correlation coefficient was used to evaluate the test-retest reliability. The Kendall's coefficient of concordance W was used to assess the consistency of GRB scores of 3 voice specialists. The nonparametric Mann-Whitney test was used to assess the differences between the dysphonia group and controls. The correlation between pVHI and GRB scores were assessed using Pearson's correlation coefficient. RESULTS: The internal consistency of total score and three subscales scores of Chinese pVHI were 0.788-0.944. The test-retest reliability was 0.631-0.887(Pâ¯<â¯.001). The pVHI scores of control group significantly were lower than the pathological group (Pâ¯=â¯.000). The GRB scores of 3 voice specialists have an excellent consistency (Wâ¯=â¯0.694-0.807, Pâ¯=â¯.000). The pVHI scores positively correlated with GRB assessment (Pâ¯<â¯.01). CONCLUSIONS: The Chinese version of pVHI had a good reliability and validity. It can be applicable and useful supplementary tool for evaluating parents' perception of their children's dysphonia.