Ultraviolet (UV) photodetectors with high responsivity and fast response are crucial for practical applications. Double perovskite Cs2AgBiBr6 has emerged as a promising optoelectronic material due to its excellent physics and photoelectric properties. However, no work is reported based on its film for photodetector applications. Herein, an ITO/SnO2/Cs2AgBiBr6/Au hole-transport layer free planar heterojunction device is fabricated for photodetector application. The device is self-powered with two responsivity peaks at 350 and 435 nm, which is suitable for ultraviolet-A (320-400 nm) and deep-blue light detecting. A high responsivity of 0.11 A W-1 at 350 nm and a quick response time of less than 3 ms are obtained, which is significantly higher than other semiconductor oxide heterojunction-based UV detectors. More importantly, the stability is significantly better than most of the hybrid perovskite photodetectors reported so far. Its photocurrent shows no obvious degradation after more than 6 months storage in ambient conditions without any encapsulation. Consequently, the utilization of Cs2AgBiBr6 film is a practical approach for high performance, large-area lead-free perovskite photodetector applications. For the mechanism, it is found that photogenerated carriers in Cs2AgBiBr6 film are separated at the Cs2AgBiBr6/SnO2 heterojunction interface by its built-in field. The low toxicity and high stability of this double perovskite active layer make it very promising for practical applications.
Despite the rapid progress that has been made in increasing the power conversion efficiency (PCE) of organic solar cells (OSCs) over the past decade, it is a challenge to realize efficient and environment-friendly OSCs. In this contribution, all polymer solar cells were fabricated with a blend of poly[4,8-bis(5-(2ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b']dithiophene-co-3-fluorothieno[3,4-b]thiophene-2-carboxylate](PTB7Th) donor and vinylene-bridged perylenediimide-based polymer (PDI-V) acceptor, in which non-halogenated tetrahydrofuran (THF) was used as the host solvent. A conventional ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/PTB7-Th:PDI-V/zirconium device structure of ITO/poly(3,4acetylacetonate(ZrAcac)/Al was employed, where PEDOT:PSS functioned as the hole transporting layer (HTL) and ZrAcac functioned as the electron transporting layer (ETL). The mixed solution of PTB7-Th and PDI-V was spin cast on the top of PEDOT:PSS layer to form the active layer. After that, ZrAcac solution was spin cast on the top of PTB7-Th:PDI-V layer. Different thermal annealing temperatures were used to optimize the active layer morphology. In details, OSCs without thermal annealing showed a PCE of 7.1%, with a short-circuit current (JSC) of 14.9 mA/cm2, an open-circuit voltage (VOC) of 0.74 V, and a fill factor (FF) of 64%. The devices annealed at 120 °C showed a high PCE of 8.1% with a JSC of 15.5 mA/cm2, a VOC of 0.74 V, and a FF of 70%. Further increasing the annealing temperature to 150 °C led to decreased FF and thereby a relatively lower PCE (7.4%). To the best of our knowledge, the PCE of ~ 8.1% is one of the highest PCE values reported in the literature so far for all polymer solar cells. The high and balanced hole and electron mobility partially contributed to such a high performance. These results suggest that THF as good non-halogenated solvent can be used to fabricate high-performance all polymer solar cells. Higher efficiency can be achieved for OSCs with THF solvent when better polymer acceptors are employed. 以聚合物PTB7-Th为给体、聚合物PDI-V为受体和四氢呋喃为溶剂，构筑了全聚合物太阳能电池.PTB7-Th与PDI-V光谱互补，有效地拓宽了活性层在可见光区的吸收范围，这有利于提高光电流.在器件优化过程中，发现热退火的方法可以有效地提高器件的光伏性能.尽管热退火处理对器件的开路电压影响不大，但是可以一定程度上提高器件的短路电流和填充因子，从而将电池的效率从7.1%提高到8.1%.8.1%的效率也是目前采用非卤素溶剂加工的基于苝酰亚胺类聚合物受体电池效率的最高值.该实验结果表明，四氢呋喃作为一种低毒性的有机非卤素溶剂，可以用来制备高性能有机光伏器件.
AIM: To determine whether weight-loss diets varying in macronutrients modulate the genetic effect of hepatocyte nuclear factor 1alpha (HNF1A) rs7957197 on weight loss and improvement of insulin resistance. MATERIALS AND METHODS: We analysed the interaction between HNF1A rs7957197 and weight-loss diets with regard to weight loss and insulin resistance improvement among 722 overweight/obese adults from a 2-year randomized weight-loss trial, the POUNDS Lost trial. The findings were replicated in another independent 2-year weight-loss trial, the Dietary Intervention Randomized Controlled Trial (DIRECT), in 280 overweight/obese adults. RESULTS: In the POUNDS Lost trial, we found that a high-fat diet significantly modified the genetic effect of HNF1A on weight loss and reduction in waist circumference (P for interaction = .006 and .005, respectively). Borderline significant interactions for fasting insulin and insulin resistance (P for interaction = .07 and .06, respectively) were observed. We replicated the results in DIRECT. Pooled results showed similar significant interactions with weight loss, waist circumference reduction, and improvement in fasting insulin and insulin resistance (P values for interaction = .001, .005, .02 and .03, respectively). Greater decreases in weight, waist circumference, fasting insulin level and insulin resistance were observed in participants with the T allele compared to those without the T allele in the high-fat diet group (P = .04, .03 and .01, respectively). CONCLUSIONS: Our replicable findings provide strong evidence that individuals with the HNF1A rs7957197 T allele might obtain more benefits in weight loss and improvement of insulin resistance by choosing a hypocaloric and high-fat diet.
In this study, mineral oil–water fluid miscibility without and with the addition of surfactant-decorated nanoparticles is experimentally and theoretically studied. First, three series of interfacial tension (IFT) tests are conducted using a spinning drop tensiometer (SDT) with the addition of hexadecyltrimethylammonium bromide (CTAB) surfactant-decorated SiO2 nanoparticles at different concentrations. Second, a new comprehensive thermodynamic model is developed to describe the fluid miscibility without and with the addition of these surfactant-decorated nanoparticles, which is also applied theoretically to reveal how the surfactant-decorated nanoparticles contribute to the thermodynamic miscibility state. The thermodynamic model developed is proven to be accurate and physically meaningful by comparing its calculated free energy of mixing with the experimental results and examples from the literature. A series of optimum conditions for the improvement of fluid miscibility by the addition of such surfactant-decorated nanoparticles are determined: a lower temperature, a higher pressure, more wetting conditions, a smaller nanoparticle radius (rNP < 40 nm), a larger surfactant concentration, and a nanoparticle concentration in the range of 0.5–0.6 wt.%. It should be noted that a higher nanoparticle concentration is required with the addition of more CTAB surfactants in order to reach the most miscible state. Moreover, the effect of surfactant concentration on the miscibility development is found to be independent of the nanoparticle radius, whereas the optimum nanoparticle concentration is reduced with increasing particle size.