Low-Temperature Graphene-Based Paste for Large-Area Carbon Perovskite Solar Cells

Carbon perovskite solar cells (C-PSCs), using carbon-based counter electrodes (C-CEs), promise to mitigate instability issues while providing solution-processed and low-cost device configurations. In this work, we report the fabrication and characterization of efficient paintable C-PSCs obtained by depositing a low-temperature-processed graphene-based carbon paste atop prototypical mesoscopic and planar n-i-p structures. Small-area (0.09 cm(2)) mesoscopic C-PSCs reach a power conversion efficiency (PCE) of 15.81% while showing an improved thermal stability under the ISOS-D-2 protocol compared to the reference devices based on Au CEs. The proposed graphene-based C-CEs are applied to large-area (1 cm(2)) mesoscopic devices and low-temperature-processed planar n-i-p devices, reaching PCEs of 13.85 and 14.06%, respectively. To the best of our knowledge, these PCE values are among the highest reported for large-area C-PSCs in the absence of back-contact metallization or additional stacked conductive components or a thermally evaporated barrier layer between the charge-transporting layer and the C-CE (strategies commonly used for the record-high efficiency C-PSCs). In addition, we report a proof-of-concept of metallized miniwafer-like area C-PSCs (substrate area = 6.76 cm(2), aperture area = 4.00 cm(2)), reaching a PCE on active area of 13.86% and a record-high PCE on aperture area of 12.10%, proving the metallization compatibility with our C-PSCs. Monolithic wafer-like area C-PSCs can be feasible all-solution-processed configurations, more reliable than prototypical perovskite solar (mini)modules based on the serial connection of subcells, since they mitigate hysteresis-induced performance losses and hot-spot-induced irreversible material damage caused by reverse biases

From single-layer graphene to HOPG: Universal functionalization strategy with perfluoropolyether for the graphene family materials

Graphene functionalization offers the opportunity to modify the chemical-physical properties of graphene, therefore broadening the variety of its possible applications. In this work, single- and few-layers graphene as well as highly oriented pyrolytic graphite (HOPG) were functionalized with perfluoropolyether (PFPE) chains via a peroxide decomposition and radical reaction. Samples were prepared using different amounts of PFPE peroxide and the effects of the treatment were studied through Raman spectroscopy, grazing angle Fourier-transform Infrared spectroscopy (GA-FTIR), X-ray Photoelectron Spectroscopy (XPS) and water contact angle measurements. A coherent trend of Fsingle bondC bonds with increasing amount of peroxidic precursor was detected, attacking the sp2 reactive sites of the grains of graphene itself and generating new sp3 hybridizations. The perfluorinated chains were found to give hydrophobic properties to graphenic layers, demonstrating the functionalization route as an easy and universal strategy for the preparation of hydrophobic graphenic substrates

IL RUOLO DELLA TIROIDECTOMIA TOTALE NELLA TIREOPATIA NODULARE PLURIFOCALE BENIGNA.

The Authors report a review of the Literature and their personal series to evaluate the role of total thyroidectomy in the surgical management of non-toxic multinodular goiter. On the basis of the data obtained, the Authors consider total thyroidectomy the therapy of choice for this pathology

Enhancing charge extraction in inverted perovskite solar cells contacts via ultrathin graphene:fullerene composite interlayers

Improving the perovskite/electron-transporting layer (ETL) interface is a crucial task to boost the performance of perovskite solar cells (PSCs). This is utterly fundamental in an inverted (p-i-n) configuration using fullerene-based ETLs. Here, we propose a scalable strategy to improve fullerene-based ETLs by incorporating high-quality few-layer graphene flakes (GFs), industrially produced through wet-jet milling exfoliation of graphite, into phenyl-C61-butyric acid methyl ester (PCBM). Our new composite ETL (GF:PCBM) can be processed into an ultrathin (∼10 nm), pinhole-free film atop the perovskite. We find that the presence of GFs in the PCBM matrix reduces defect-mediated recombination, while creating preferential paths for the extraction of electrons towards the current collector. The use of our GF-based composite ETL resulted in a significant enhancement in the open circuit voltage and fill factor of triple cation-based inverted PSCs, boosting the power conversion efficiency from ∼19% up to 20.8% upon the incorporation of GFs into the ETL