RESUMO
Interface engineering is one of the promising strategies for the long-term stabilization of perovskite solar cells (PSCs), preventing chemical decomposition induced by external agents and promoting fast charge transfer. Recently, MXenes-2D structured transition metal carbides and nitrides with various functionalization (O, -F, -OH) have demonstrated high potential for mastering the work function in halide perovskite absorbers and have significantly improved the n-type charge collection in solar cells. This work demonstrates that MXenes allow for efficient stabilization of PSCs besides improving their performances. A mixed composite bathocuproine:MXene, that is, (BCP:MXene) interlayer, is introduced at the interface between an electron-transport layer (ETL) and a metal cathode in the p-i-n device structure. The investigation demonstrates that the use of BCP:MXene interlayer slightly increases the power conversation efficiency (PCE) for PSCs (from 16.5 for reference to 17.5%) but dramatically improves the out of Glove-Box stability. Under ISOS-L-2 light soaking stress at 63 ± 1.5 °C, the T80 (time needed to reduce efficiency down to 80% of the initial one) period increases from 460 to > 2300 hours (h).
RESUMO
A new dual-functional implant based on gellan-xanthan hydrogel with calcium-magnesium silicate ceramic diopside and recombinant lysostaphin and bone morphogenetic protein 2 (BMP-2)-ray is developed. In this composite, BMP-2 is immobilized on microparticles of diopside while lysostaphin is mixed directly into the hydrogel, providing sustained release of BMP-2 to allow gradual bone formation and rapid release of lysostaphin to eliminate infection immediately after implantation. Introduction of diopside of up to 3% (w/v) has a negligible effect on the mechanical properties of the hydrogel but provides a high sorption capacity for BMP-2. The hydrogels show good biocompatibility and antibacterial activity. Lysostaphin released from the implants over a 3 h period efficiently kills planktonic cells and completely destroys 24 h pre-formed biofilms of Staphylococcus aureus. Furthermore, in vivo experiments in a mouse model of critically-sized cranial defects infected with S. aureus show a complete lack of osteogenesis when implants contain only BMP-2, whereas, in the presence of lysostaphin, complete closure of the defect with newly formed mineralized bone tissue is observed. Thus, the new implantable gellan-xanthan hydrogel with diopside and recombinant lysostaphin and BMP-2 shows both osteogenic and antibacterial properties and represents a promising material for the treatment and/or prevention of osteomyelitis after bone trauma.
RESUMO
Carbon quantum dots (CQDs) are an excellent eco-friendly fluorescence material, ideal for various ecological testing systems. Herein, we establish uniform microwave synthesis of the group of carbon quantum dots with specific functionalization of ethylenediamine, diethylenetriamine, and three types of Trilon (A, B and C) with chelate claws -C-NH3. CQDs' properties were studied and applied in order to sense metal cations in an aquatic environment. The results provide the determination of the fluorescence quench in dots by pollutant salts, which dissociate into double-charged ions. In particular, the chemical interactions with CQDs' surface in the Irving-Williams series (IWs) via functionalization of the negatively charged surface were ascribed. CQD-En and CQD-Dien demonstrated linear fluorescence quenching in high metal cation concentrations. Further, the formation of claws from Trilon A, Trilon B, and C effectively caught the copper and nickel cations from the solution due to the complexation on CQDs' surface. Moreover, CQD-Trilon C presented chelating properties of the surface and detected five cations (Cu2+, Ni2+, Ca2+, Mg2+, Zn2+) from 0.5 mg/mL to 1 × 10-7 mg/mL in the Irving-William's series. Dependence was mathematically attributed as an equation (ML regression model) based on the constant of complex formation. The reliability of the data was 0.993 for the training database.