Trifluoromethyl Benzylamine Research Articles

Molecular Engineering of 2D Spacer Cations to Achieve Efficient and Stable 2D/3D Perovskite Solar Cells

Introducing 2D perovskite onto the surface of 3D perovskite could not only passivate the defects in 3D perovskite, but also protect the 3D perovskite from humidity invasion, which could improve the device stability. The choice of spacer cations in 2D perovskites directly influences the overall properties of the 2D layer, which is crucial to the efficiency and stability of devices. Herein, trifluoromethyl benzylamine is developed as the 2D spacer cation, and the effects of –CF3 at different substitution positions on the surface morphology, carrier dynamics, and device performances are systematically investigated. Results show that the 3‐TFPMAI‐treated 2D/3D perovskite film shows smoother morphology, with fewer surface defects and less nonradiative recombination. Moreover, with a matched energy level, 3‐TFPMAI modification can accelerate hole extraction and hole transporting. The 3‐TFPMAI‐treated 2D/3D cell achieves a champion efficiency of 22.68%. What's more, the introduction of fluoride‐containing groups increases the hydrophobicity of the 2D layer, which effectively resists moisture erosion and greatly improves the long‐term and operational stability of the perovskite solar cells.

Selective hydrophobic decoration of metal-organic framework for effective removal of ppb-level CH3I from humid streams

Recently, effective removal of toxic gases from humid streams has been an urgent global issue, especially at low concentrations due to increase in air pollutant emission standards. In this work, a series of selectively modified MIL-101 s was prepared by blocking coordinatively unsaturated sites (CUSs) with hydrophobic amine compounds containing –F or long alkyl groups. The nucleophilic quinuclidine (QN) was consecutively encapsulated into the pores of hydrophobic MIL-101 s to remove CH3I by alkylation. The direct correlation between the hydrophobic index (HI) of adsorbents and the CH3I removal performance in a humid environment was systematically investigated for the first time by progressively blocking the CUSs with different amounts of hydrophobic amines including 4-(trifluoromethyl) benzylamine (TFM-BA). Among them, QN@MIL-101-TFM-BA exhibited the unprecedented removal efficiency exceeding 99.999% at 303 K and RH 95% for 11 days, outperforming over 280 times compared to the conventional adsorbents. The strong affinity between QN and CH3I is thoroughly investigated by X-ray photoelectron spectroscopy (XPS) and elemental mapping. MIL-101-TFM-BA showed outstanding removal performance even for HCHO, proving the versatile use of the prepared hydrophobic metal–organic frameworks adsorbents in realistic condition.

Efficient and stable perovskite solar cells via surface passivation of an ultrathin hydrophobic organic molecular layer

Organic and inorganic metal halide perovskite solar cells (PSCs) with an outstanding performance of low-cost manufacturing and low-temperature solution processing, have been regarded as the next-generation photovoltaic technology. However, the solution processed perovskite films usually have abundant defects, especially at the grain boundaries and surfaces, causing carrier recombination, hysteresis, and degradation. Herein, 4-(trifluoromethyl)benzylamine (TFMBA) is deposited on the surface of perovskites to form an ultrathin hydrophobic organic molecular layer, passivating the interfacial imperfections. By optimizing the post-treatment conditions, a remarkable power conversion efficiency (PCE) of 20.56% is realized based on Cs0.05(FA0.85MA0.15)0.95Pb(I0.85Br0.15)3 perovskite. Impressively, the passivated ultrathin organic molecular layer effectively prohibits the penetration of moisture, resulting in unsealed PSCs retaining 84% of the original PCE after aged 1300 h at 65%−75% relative humidity (RH). SEM and XRD confirm that TFMBA can effectively passivate defects on the surface and grain boundaries, thereby prevent the perovskites from the irreversible decomposition with the immersion of moisture. This suggests that the TFMBA post-treatment has great potential in obtaining high-quality and stable perovskite films.

Conformational analysis, spectroscopic, structure–activity relations and quantum chemical simulation studies of 4–(trifluoromethyl)benzylamine

The FT–IR and FT–Raman spectra of 4–trifluoromethylbenzylamine (TFMBA) have been recorded in the range 4000–450 and 4000–100 cm−1 respectively. The conformational analysis of the compound has been carried out to attain stable geometry of the compound. The complete vibrational assignment and analysis of the fundamental modes of the compound are carried out using the experimental FTIR and FT–Raman data and quantum chemical studies. The experimental vibrational frequencies are compared with the wavenumbers obtained theoretically from the B3LYP gradient calculations employing the standard high level 6–311++G** and cc–pVTZ basis sets for the optimised geometry of the compound. The structural parameters, thermodynamic properties and vibrational frequencies of the normal modes obtained from the B3LYP methods are in good agreement with the experimental data. The 1H (400 MHz; CDCl3) and 13C (100 MHz; CDCl3) nuclear magnetic resonance (NMR) spectra were also recorded. The electronic properties, highest occupied molecular orbital and lowest unoccupied molecular orbital energies are measured by DFT approach. The charges of the atoms by natural bond orbital (NBO) analysis are determined by B3LYP/cc–pVTZ method. The structure–chemical reactivity relations of the compound are determined through chemical potential, global hardness, global softness, electronegativity, electrophilicity and local reactivity descriptors by conceptual DFT methods.

Cyclodextrin – ferrocene host – guest complexes on silicon oxide surfaces

Research on carbohydrate‐based interactions with proteins, nucleic acids, or antibodies has gained increased interest in the last years especially in clinical diagnosis or drug development. The efficiency of diagnostic interfaces depends upon the number of probe molecules, e.g., carbohydrates. The control of surface parameters as density and distribution of immobilized carbohydrates is essential for a reliable interaction with protein analytes. A controlled production of biomolecular interfaces can be reached by a stepwise quality control during buildup of these biointerfaces.Here, ß‐amino‐cyclodextrin molecules were attached to amine‐reactive silicon oxide surfaces via click chemistry to construct a model biosensor surface. The amount of surface bound carbohydrates was determined indirectly after chemical derivatization with 4‐(trifluoromethyl)‐benzylamine (TFMBA). Moreover, these surfaces were used to form host–guest complexes of ferrocene (guest) and β‐cyclodextrin (host) moieties to mimic the target binding (sensing) of the model biosensor. Surface chemical analysis of all steps during biosensor construction was performed using X‐ray photoelectron spectroscopy and near‐edge X‐ray absorption fine structure spectroscopy. Our approach widens the possibilities to generate switchable surfaces based on ß‐cyclodextrin surfaces for biosensor applications. Copyright © 2016 John Wiley & Sons, Ltd.

Functional group quantification on epoxy surfaces by chemical derivatization (CD)‐XPS

In this study, epoxy‐terminated silicon oxide surfaces were chemically derivatized with trifluoroacetic anhydride (TFAA) and 4‐(trifluoromethyl)‐benzylamine (TFMBA) and analyzed by X‐ray photoelectron spectroscopy, near‐edge X‐ray absorption fine structure spectroscopy and water contact angle measurements. TFAA was used for quantitative derivatization to determine the amount of reactive epoxy groups on these surfaces. Furthermore, epoxy‐terminated surfaces were derivatized with TFMBA (a model compound for biomolecules with an amino linker) yielding secondary amines because of formation of covalent C–N bonds between TFMBA and the epoxy films. Fluorine being part of TFAA and TFMBA composition was used to follow the progress of the chemical derivatization reaction. Both derivatization agents – TFAA and TFMBA – gave comparable reaction yields of ~60% on epoxy silicon surfaces, whereas on epoxy glass slides, the derivatization yields were considerably lower (30–40%).The protocol for attachment of TFMBA (model compound) on epoxy‐modified surfaces was adapted to (bio)molecules with an amino linker, e.g. carbohydrates to prepare carbohydrate‐functionalized biointerfaces. Copyright © 2014 John Wiley & Sons, Ltd.