Direct Electronic Property Imaging of a Nanocrystal-Based Photovoltaic Device by Electron Beam-Induced Current via Scanning Electron Microscopy

Scanning electron microscopy (SEM) electron beam-induced current (EBIC) studies were performed on the cross-section of a nanocrystal-based hybrid bulk heterojunction photovoltaic device. Using these techniques, the short circuit carrier collection efficiencies are mapped with a better than 100 nm resolution. Electronically deficient and proficient regions within the photoactive layer are determined. The results show that only a fraction of the CdSe nanorod:P3HT layer (P3HT = poly-3­(hexylthiophene)) at the Al cathode interface shows primary collection of charged carriers, in which the photoactivity decreases exponentially away from the interface. The recombination losses of the photoactive layer away from this interface prove that the limiting factor of the device is the inability for electrons to percolate between nanoparticles; to alleviate this problem, an interparticle network that conducts the electrons from one nanorod to the next must be established. Furthermore, the EBIC technique applied to the nanocrystalline device used in this study is the first measurement of its kind and can be applied toward other similar architectures

Structural Impact on Dielectric Properties of Zirconia

Zirconium hydroxide powders were calcined at 100, 250, 500, and 1000 °C to study the effects of porosity, surface area, structure, and electronic properties as a function of temperature. Characterization techniques such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), ultraviolet–visible (UV–vis) spectroscopy, and transmission electron microscopy (TEM) demonstrated that the powder surface area and porosity decreased as the material changed from an amorphous phase to a monoclinic crystal structure. Impedance analysis showed both the dielectric constants and capacitance decreased by 2 orders of magnitude as crystallinity increased, correlating to a lowered concentration of defects, such as surface hydroxyl groups that contribute to leakage current

Dataset.

BackgroundThe cochlear implant (CI) has proven to be a successful treatment for patients with severe-to-profound sensorineural hearing loss, however outcome variance exists. We sought to evaluate particular mutations discovered in previously established sensory and neural partition genes and compare post-operative CI outcomes.Materials and methodsUtilizing a prospective cohort study design, blood samples collected from adult patients with non-syndromic hearing loss undergoing CI were tested for 54 genes of interest with high-throughput sequencing. Patients were categorized as having a pathogenic variant in the sensory partition, pathogenic variant in the neural partition, pathogenic variant in both sensory and neural partition, or with no variant identified. Speech perception performance was assessed pre- and 12 months post-operatively. Performance measures were compared to genetic mutation and variant status utilizing a Wilcoxon rank sum test, with PResultsThirty-six cochlear implant patients underwent genetic testing and speech understanding measurements. Of the 54 genes that were interrogated, three patients (8.3%) demonstrated a pathogenic mutation in the neural partition (within TMPRSS3 genes), one patient (2.8%) demonstrated a pathogenic mutation in the sensory partition (within the POU4F3 genes). In addition, 3 patients (8.3%) had an isolated neural partition variance of unknown significance (VUS), 5 patients (13.9%) had an isolated sensory partition VUS, 1 patient (2.8%) had a variant in both neural and sensory partition, and 23 patients (63.9%) had no mutation or variant identified. There was no statistically significant difference in speech perception scores between patients with sensory or neural partition pathogenic mutations or VUS. Variable performance was found within patients with TMPRSS3 gene mutations.ConclusionThe impact of genetic mutations on post-operative outcomes in CI patients was heterogenous. Future research and dissemination of mutations and subsequent CI performance is warranted to elucidate exact mutations within target genes providing the best non-invasive prognostic capability.</div

Post-operative z-score of patients with identified variance of unknown significance.

Post-operative z-score of patients with identified variance of unknown significance.</p