The bio-synthesis of nanomaterials is emerging as an innovative methodology, which is comparatively eco-friendly and inexpensive. Among different microbes, the role of fungi has been proved considerably promising in the in-vitro synthesis of nanomaterials. In this study, the comparative efficacy of four different species of Aspergillus (A. fumigatus, A. niger, A. fiavus and A. terreus) was investigated for the synthesis of silver nanoparticles (AgNPs). Initially, the synthesis was monitored through changes in coloration (yellow to dark brown) of the reaction solution containing AgNO3 reacted with the fungal biomass, of each fungi for 96 hours (hr) at 28 degrees C. The UV-visible spectra of the reaction mixture taken at different times showed a gradual change in absorbance between 400-420 nm, corresponding to changes in the surface plasmon resonance of the Ag metal. Comparatively, A. fumigatus showed a higher rate of nanoparticle synthesis than the other fungi. X-Ray Diffraction (XRD) spectra showed peaks of various intensities, with respect to the angle of diffraction (2 theta), thus, revealing the crystalline nature of AgNPs. Nanoparticles fabricated through A. fumigatus (5-18 nm) and A. flavus (13-26 nm) exhibited more drift towards monodispersity, which was relatively higher (6-70 nm) than in the other two fungi. Transmission Electron Microscopy (TEM) further confirmed the configuration of AgNPs in the range of 3-80 nm. (C) 2014 Sharif University of Technology. All rights reserved.
The hole transport materials that interact with the indium tin oxide (ITO) surface can be processed into monomolecular layers (MLs), which often exhibit different surface and electronic properties than their thin‐film counterparts. Herein, it is found that poly[bis(4‐phenyl)(2,4,6‐trimethylphenyl)amine] (PTAA) films (R‐PTAA) can be easily processed into ML (M‐PTAA) due to the van der Waals interaction between ITO and PTAA. However, compared with R‐PTAA, the work function (WF) and conductivity of M‐PTAA are simultaneously reduced by the charge transfer at the ITO/PTAA interface. To address this issue, a modified monomolecular layer strategy (m‐MLS) is developed, where a small amount of 2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane (F4TCNQ) is introduced to enhance the interaction force between ITO and PTAA. PTAA treated by m‐MLS (F‐PTAA) has a hydrophilic physical surface, closely matching electronic energy level with the perovskite layer and smaller bulk resistance. As a result, the efficiency and reproducibility of perovskite solar cells (PSCs) are substantially improved. PSCs based on F‐PTAA demonstrated the highest power conversion efficiency (PCE) of 19.7% with a fill factor of over 80%. This study inspires the development of novel interface modification materials, and provides a simple and convenient direction for the fabrication of high‐performance and reproducible inverted PSCs with high fill factors.
Metal-organic frameworks (MOFs) are favorable hosting materials for fixing enzymes to construct enzyme@MOF composites and to expand the applications of biocatalysts. However, the rigid structure of MOFs without tunable hollow voids and a confinement effect often limits their catalytic activities. Taking advantage of the smart soft polymers to overcome the limitation, herein, a protection protocol to encapsulate the enzyme in zeolitic imidazolate framework-8 (ZIF-8) was developed using a glutathione-sensitive liposome (L) as a soft template. Glucose oxidase (GOx) and horseradish peroxidase (HRP) were first anchored on a light- and thermoresponsive porous poly(styrene-maleic anhydride-
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