Open-circuit voltage enhancement of inverted polymer bulk heterojunction solar cells by doping NaYF4 nanoparticles/PVP composites

NaYF nanoparticles (NPs) were synthesized by a facile solvothermal approach using polyvinylpyrrolidone (PVP) as a surfactant. The NPs were doped into P3HT:PCBM blend to fabricate inverted polymer bulk heterojunction (BHJ) solar cells. The dependence of device performance on the weight ratio of NPs in the blend film was investigated. The results showed that the open-circuit voltage was apparently enhanced by doping NaYF NPs/PVP composites into the active layer while maintaining the short-circuit current density and fill factor, leading to an increase in power conversion efficiency. The results of cyclic voltammetry measurement revealed that PVP had a deeper HOMO energy level than that of P3HT. PVP carried by NPs might also form charge transfer (CT) complexes with PCBM, which can make contributions to the open-circuit voltage. The study of photoluminescence (PL) spectra indicated clear evidence for enhanced exciton dissociation and reduced charge recombination in the blend film with NPs

Light-Up Nonthiolated Aptasensor for Low-Mass, Soluble Amyloid‑β₄₀ Oligomers at High Salt Concentrations

Herein, a light-up nonthiolated aptasensor was developed for low-mass, soluble amyloid-β₄₀ oligomers (LS-Aβ_40‑O). Au nanoparticles (AuNP) were employed as colorimetric probes, and the nonthiolated aptamers (Apt) were adsorbed on AuNP surfaces, acting as binding elements for LS-Aβ_40‑O. The aggregation of AuNPs was induced when Apt-modified AuNPs (Apt@AuNPs) were under high-salt conditions. However, upon the addition of LS-Aβ_40‑O into the Apt@AuNP solution, the salt tolerance of the AuNPs was greatly enhanced. Further studies confirmed that the formed LS-Aβ_40‑O–Apt complex attached onto the AuNP surfaces via interactions between LS-Aβ_40‑O and Au, which led to electrostatic and steric stabilization of the AuNPs under high-salt conditions. On the basis of this outcome, a sensitive light-up nonthiolated aptasensor for LS-Aβ_40‑O was achieved with a detection limit of 10.0 nM and a linear range from 35.0 to 700 nM in a 175 mM NaCl solution. Cerebrospinal-fluid (CSF) samples from healthy persons and Alzheimer’s disease (AD) patients were successfully distinguished by using this proposed method. The concentrations of LS-Aβ_40‑O in the CSF of AD patients were of nanomolar grade, but there was no detectable LS-Aβ_40‑O in those of the healthy persons. This work provides a new insight into the interaction between Apt@AuNPs and Aβ_40‑O and also develops a simple, rapid, highly selective and sensitive, and applicable method for LS-Aβ_40‑O detection in real CSF samples, which is significant for the diagnosis of AD