Broadband photodetectors from silane-passivated CsPbBr3 nanocrystals by ultrasound-mediated synthesis.

Perovskite nanocrystals have excellent optical properties but suffer from environmental instability and production up-scaling which limit their commercial application. Here, we report the gram-scale ultrasound-mediated synthesis of silane passivated CsPbBr3 nanocrystals using (3-aminopropyl) triethoxysilane (APTS) as the primary surface ligand surface. The surface engineering endowed the CsPbBr3@SiOR NCs with extended environmental stability, a narrow emission bandwidth and a high photoluminescence quantum yield (PLQY > 75%). Thanks to these excellent optical properties, high-efficiency lateral and vertical photodetectors were fabricated. In particular, the layered vertical photodiode composed of ITO/Ga2O3/CsPbBr3/Au exhibited a broadband photoresponse from 350-700 nm with a responsivity peaking at 44.5.1 A W-1 and specific detectivity above 1013 Jones when illuminated at 470 nm wavelength and biased at +5 V. These results correspond to the best-in-class performance perovskite nanocrystal PD and confirm the extraordinary potential of CsPbBr3@SiOR for the development of efficient optoelectronic devices.

Highly emissive MAPbBr3perovskite QDs by ligand-assisted reprecipitation: the antisolvent effect.

A systematic study of the synthetic procedure to improve quantum efficiency of luminescent hybrid perovskite QDs through ligand-assisted precipitation method is presented. Particularly, the influence of the dielectric constant and dipole moment of the antisolvent on the reaction time and the photophysical properties of the QDs is highlighted. After evaluating the influence of antisolvents and optimizing experimental parameters such as reaction time and Pb excess of the precursor, colloidal crystalline MAPbBr3QDs with exceptionally high absolute quantum yield up to 97.7% in solution and 69.1% in solid film were obtained. Finally, MAPbBr3QDs precipitated from anisole were processed like UV-curable nanocomposite as efficient down conversion layer resulting in very narrow green emission light-emitting diode.

Efecto hipoglucémico del extracto acuoso de Chuquiraga jussieui J.F. Gmel en ratas con diabetes inducida / Hypoglycemic effect of aqueous extract from Chuquiraga jussieui J.F. Gmel in rats with induced diabetes

Introducción: la Chuquiraga Jussieui J.F. Gmel es una planta silvestre que crece en los Andes ecuatorianos y es utilizada ampliamente por las culturas ancestrales y la población común como medicina folclórica, especialmente como antidiabético, antinflamatorio y febrífugo. Objetivos: evaluar el efecto hipoglucémico del extracto acuoso de la Chuquiraga jussieui, en ratas con diabetes inducida. Métodos: para la determinación del efecto hipoglucémico, se utilizaron ratas de la línea isogénica Wistar con hiperglicemia inducida. Se trabajó con 6 grupos (control normal sin tratamiento, control hiperglicémico con estreptozotocina, control hiperglicémico tratado con fármaco hipoglucemiante glibenclamida, y 3 concentraciones del extracto acuoso 100, 200 y 400 mg/kg de peso corporal, del extracto de Chuquiraga jussieui. Los resultados fueron evaluados estadísticamente, mediante pruebas de distribución normal con el test de Shapiro wilk y homogeneidad de varianza por el test de Levene, análisis de varianza entre los grupos y comparaciones múltiples (Tukey). Resultados: el grupo con estreptozotocina bajo el efecto solamente de la hiperglicemia inducida y sin tratamiento alguno, mostró aumentos significativos de las medias de glicemia durante todo el tiempo del estudio; El grupo con glibenclamida presentó una disminución significativa en más de 8 mmol L-1 de diferencia, igualmente sucedió con los grupos de tres concentraciones de extracto 100, 200 y 400 mg/Kg tratados con los diferentes niveles de extracto de la planta en estúdio, y resultó mayor el contraste en el último grupo. Conclusiones: se determinó que el extracto acuoso de Chuquiraga jussieui J. F Gmel presenta efecto hipoglucemiante a partir de 400 mg Kg-1 frente a un fármaco en un modelo para diabetes mellitus tipo 2.

Introduction: Chuquiraga jussieui J.F. Gmel is a wild plant species that grows in the Ecuadorian Andes. It is broadly used by ancestral cultures and the common population as folk medicine, particularly as antidiabetic, anti-inflammatory and febrifuge. Objectives: Determine the hypoglycemic effect of aqueous extract from Chuquiraga jussieui in rats with induced diabetes. Methods: Determination of the hypoglycemic effect was conducted in rats from the Wistar isogenic line with induced hyperglycemia. Six groups were formed: normal control without treatment, hyperglycemic control with streptozotocin, hyperglycemic control treated with the hypoglycemic drug glibenclamide, and aqueous extract from Chuquiraga jussieui at three concentrations (100, 200 and 400 mg/kg body weight). Statistical assessment of results included normal distribution by the Shapiro­Wilk test, variance homogeneity by Levene's test, analysis of variance between the groups, and multiple comparisons by Tukey's tests. Results: The streptozotocin group with induced hyperglycemia and no treatment showed a significant mean glycemia increase throughout the study. The glibenclamide group showed a significant decrease of over 8 mmol/l, and so did the three extract groups (concentrations of 100, 200 and 400 mg/kg) treated with various volumes of extracts from the study plant, the contrast being greater in the latter group. Conclusions: It was determined that aqueous extract from Chuquiraga jussieui J.F. Gmel displays hypoglycemic activity as of 400 mg/kg versus a drug in a model for type 2 diabetes mellitus.