Construction of Multifunctional and Adjustable Langmuir–Blodgett Composite Films Containing Black Phosphorus with High Stability for Optically Electrical Applications

Abstract

Fabrication of composite thin-film materials based on black phosphorus (BP) will greatly broaden the applications of BP in various areas. However, it is still a challenge to prepare a BP-based composite film with good stability and controllable structure. In this work, a series of BP-based composite Langmuir−Blodgett (LB) films are prepared by the selfassembly of polyethyleneimine (PEI)-modified BP nanosheets (BPNSs) (BPNS-PEI) and dye molecules. The presence of PEI greatly improves the stability of BPNSs. As for BPNS-PEI and dye molecules, the electrostatic interactions or π−π stacking interactions ensure the formation of stable composite LB films. Due to the protonation and deprotonation of amino groups, the synthesized BPNS-PEI/dye composite films show a sensitive response to acid and alkali gases, which shows wide application prospects as a highly sensitive gas sensor. Furthermore, surface-enhanced Raman scattering (SERS) proves that the prepared LB films exhibit good reproducibility and obvious Raman enhancement effect on rhodamine 6G molecules. In addition, due to the high carrier transfer rate of the obtained composite films, they possess enhanced photocurrent generation performance than pure BPNS-PEI and pure dye films. The current work demonstrates an effective method for preparing the ordered self-assembled BP-based composite LB films with good SERS and photoelectric conversion performance.

Gas-Responsive and Self-Powered Visual Composite Langmuir–Blodgett Films for Ultrathin Gas Sensors

“…The mechanism of the acid–alkali response is shown in Figure g. The interface structure and charge transfer of the LB films can be affected by heteroatoms in the subphase (like nitrogen atoms) and the molecular structure of the films . For the carbazole molecules/MO LB films, influenced by the external acid–alkali gases atmosphere, we speculate that the acidic sulfonic acid and the alkali dimethylamino in the MO form a conjugated system of p -aminoquinone structure, which changes the internal structure of the composite films and affects the charge transfer .…”

“…The interface structure and charge transfer of the LB films can be affected by heteroatoms in the subphase (like nitrogen atoms) and the molecular structure of the films. 25 For the carbazole molecules/MO LB films, influenced by the external acid− alkali gases atmosphere, we speculate that the acidic sulfonic acid and the alkali dimethylamino in the MO form a conjugated system of p-aminoquinone structure, which changes the internal structure of the composite films and affects the charge transfer. 26 For the other two composite films, the color change of the films may be attributed to the protonation and deprotonation of the N−H and −NH 2 groups in the dye molecules.…”

Enhanced thermal transportation across an electrostatic self-assembly of black phosphorene and boron nitride nanosheets in flexible composite films

“…S3†), and distinct signal peaks appeared at positions 359.8, 435.1, and 463.3 cm −1 of the spectrum, corresponding to the Raman shifts caused by the A 1 g , B 2g , and A 2 g lattice vibrations of BP, respectively. 25,26,30,31 Strong diffraction peaks at 17.1°, 34.3°, and 52.4° are seen in the XRD image in Fig. 2g, representing the (020), (040), and (060) crystal planes of BP, respectively.…”

“…21 The reported thermal conductivities of monolayer BP along the zigzag crystallographic direction, armchair direction, and through-plane are about 101, 36, and 5.5 W m −1 K −1 , respectively, as assessed by the time-resolved magneto-optical Kerr effect. 22 At present, BP is mainly used in photoelectric functional devices, 23,24 photosensitive thin films, 25 and other research fields, while research on BP-containing fillers as thermal management materials has rarely been conducted. Therefore, it is interesting and meaningful to investigate the potential of BP as a filler to enhance the thermal transport performance of thermal management materials.…”

Chlorination‐Mediated π–π Stacking Enhances the Photodynamic Properties of a NIR‐II Emitting Photosensitizer with Extended Conjugation

“…The result implies that BMIC-BO-4Cl exhibits higher charge separation efficiency of photogenerated electron-hole pairs. [17] Next, the charge transfer properties of the two materials were characterized by electronic conductivity via the electrochemical impedance spectroscopy (EIS) technique (Figure 2f). The charge transfer resistance can be read out from the semicircle's diameter of the Nyquist plot.…”