Triple Cross-Linking Engineering Strategies for Efficient and Stable Inverted Flexible Perovskite Solar Cells.

Inverted flexible perovskite solar cells (fPSCs) are promising for commercialization due to their low cost, lightweight, and excellent stability. However, enhancing fPSCs' power conversion efficiency and stability remains challenging. Here, an unprecedented triple cross-linking engineering strategy is innovatively exhibit for efficient and stable inverted fPSCs. First, a carefully designed cross-linker, 4-fluorophenyl 5-(1,2-dithiolan-3-yl) pentanoate (FB-TA), is added to the perovskite precursor solution. During the perovskite film's crystallization at a low temperature, the cross-linking product of FB-TA can passivate the grain boundaries and reduce the film's residual strain and Young's module. Then, FB-TA is also introduced for the bottom- and top-interface modification of the perovskite film. The interfacial treating strategy protects the perovskite from water invasion and strengthens the interfaces. The combination of triple strategies affords highly efficient inverted fPSCs with a champion efficiency of 21.42% among the state-of-the-art inverted fPSCs based on nickel oxides. More importantly, the flexible devices also exhibit superior stabilities with T90 >4000 bending cycles, photostability with T90 >568 h, and ambient stability with T90 >2000 h, especially the stability with T80 >1120 h under harsh damp-heat conditions (i.e., 85 °C and 85% RH). The strategy provides new insights into the industrialization of high-performance and stable fPSCs.

Improvement in Dibenzofuran-Based Hole Transport Materials for Flexible Perovskite Solar Cells.

The π-conjugated system and the steric configuration of hole transport materials (HTMs) could greatly affect their various properties and the corresponding perovskite solar cells' efficiencies. Here, a molecular engineering strategy of incorporating different amounts of p-methoxyaniline-substituted dibenzofurans as π bridge into HTMs was proposed to develop oligomer HTMs, named mDBF, bDBF, and tDBF. Upon extending the π-conjugation of HTMs, their HOMO energy levels were slightly deepened, significantly increasing the thermal stability and hole mobility. The incorporation of p-methoxyaniline bridges built one or two additional triphenylamine propeller structures, resulting in a denser film. Here, the tDBF-based n-i-p flexible perovskite solar cells createdchampion efficiency, giving a power conversion efficiency of 19.46%. And the simple synthesis and purification process of tDBF contributed to its low manufacturing cost in the laboratory. This work provided a reference for the development of low-cost and efficient HTMs.

Bimetallic Fe/Ni nanoparticles derived from green synthesis for the removal of arsenic (V) in mine wastewater.

Since the incidences of arsenicosis have significantly increased worldwide in the last decade, remediation of arsenic (As) pollution is now imperative. In this study, calcined green synthesized Fe/Ni nanoparticles (C-Fe/Ni NPs) were evaluated for their efficacy for As (V) removal from aqueous solution. Under optimal experimental conditions As (V) removal efficiency reached 87.3%. Analysis of changes in the surface properties of C-Fe/Ni NPs before and after interaction with As (Ⅴ) using a range of advanced characterization techniques including IC-AFS, SEM-EDS, XPS and XRD revealed that the As removal mechanism involved only adsorption. Adsorption kinetics followed a pseudo-second order rate model (R2 > 0.986) and adsorption best fit the Langmuir isotherm model (R2 > 0.958). Thermodynamic studies indicated that adsorption was a spontaneous endothermic process. On the basis of these results, a removal mechanism of As (Ⅴ) by C-Fe/Ni NPs was proposed. Finally, the efficacy of the material for practical remediation of As from aqueous solution was assessed, including the influence of coexisting anions. While Cl-, NO3- and SO42- had little influence on As (V) removal, both H2PO4- and HCO3- significantly negatively affected removal.

Removal mechanism of 17ß-estradiol by carbonized green synthesis of Fe/Ni nanoparticles.

Even a small concentration of estrogen released into the environment can cause great damage to the surrounding ecosystem, with potential teratogenic and carcinogenic hazards to many organisms. In this study, carbonized green synthesized Fe/Ni NPs, with a maximum adsorption capacity of 44.32 mg g-1 coupled with over 98.3% removal efficiency, were used to remove 17ß-estradiol (E2) from water. Adsorption best conformed to pseudo-second-order kinetics (R2 = 0.998-0.999) and the Freundlich model (R2 = 0.990-0.997). SEM images reveal that the carbonized material had increased specific surface area and pores. Zeta Potential, FTIR and XPS spectra confirmed that carbonized material was negatively charged and contained functional groups with a high affinity for E2. Liquid chromatography during removal of E2 suggested no new substances were generated. Therefore, the synergistic effect of carbonized-Fe/Ni NPs surface functional groups is a key issue, including dehydration bonds, hydrogen bonds, and the accumulation of Π and Π. In practice the application of carbonized-Fe/Ni NPs demonstrated their ability to remove 51.8% and 48.7% of E2 from domestic sewage and livestock wastewater, respectively. This work provides a strong basis for the practical removal of E2 using carbonized-Fe/Ni NPs material.

Simultaneous removal of mixed contaminants triclosan and copper by green synthesized bimetallic iron/nickel nanoparticles.

The mixed contamination of environmental matrices by antibacterial agents and heavy metals has attracted much attention worldwide due to the complex nature of their environmental interactions and their potential toxicity. In this work, green synthesized bimetallic iron/nickel nanoparticles (Fe/Ni NPs) was used to simultaneously remove triclosan (TCS) and copper (Cu (II)) under optimal experimental conditions with removal efficiencies of 75.8 and 44.1% respectively. However, in a mixed contaminant system the removal efficiencies of TCS and Cu (II) were lower than when TCS (85.8%) and Cu (II) (52.5%) were removed separately, suggesting that there was competitive relationship between the two contaminants and Fe/Ni NPs used for remediation. SEM-EDS, XRD and FTIR all indicated that both TCS and Cu (II) were adsorbed onto Fe/Ni NPs. Furthermore, while XPS showed that Cu (II) was reduced to Cu0, GC-MS analysis showed that TCS also underwent degradation with 2,7/2,8-Cl2DD as the major intermediate. The adsorption of both contaminants fit well a pseudo second order kinetic model (R2>0.998) and the Freundlich isotherm (R2>0.905). Whereas the reduction kinetics obeyed a pseudo first order model. Thus, overall the removal of TCS and Cu (II) involved a combination of both adsorption and reduction. Finally, a removal mechanism for triclosan and Cu (II) was proposed. Overall, Fe/Ni NPs have the potential to practically coinstantaneously remove both TCS and Cu (II) from aqueous solution under a wide range of conditions.