A Cruciform Electron Donor–Acceptor Semiconductor with Solid‐State Red Emission: 1D/2D Optical Waveguides and Highly Sensitive/Selective Detection of H₂S Gas

Abstract

In this paper, a new cruciform donor–acceptor molecule 2,2'‐((5,5'‐(3,7‐dicyano‐2,6‐bis(dihexylamino)benzo[1,2‐b:4,5‐b']difuran‐4,8‐diyl)bis(thiophene‐5,2‐diyl))bis (methanylylidene))dimalononitrile (BDFTM) is reported. The compound exhibits both remarkable solid‐state red emission and p‐type semiconducting behavior. The dual functions of BDFTM are ascribed to its unique crystal structure, in which there are no intermolecular face‐to‐face π–π interactions, but the molecules are associated by intermolecular CN…π and H‐bonding interactions. Firstly, BDFTM exhibits aggregation‐induced emission; that is, in solution, it is almost non‐emissive but becomes significantly fluorescent after aggregation. The emission quantum yield and average lifetime are measured to be 0.16 and 2.02 ns, respectively. Crystalline microrods and microplates of BDFTM show typical optical waveguiding behaviors with a rather low optical loss coefficient. Moreover, microplates of BDFTM can function as planar optical microcavities which can confine the emitted photons by the reflection at the crystal edges. Thin films show an air‐stable p‐type semiconducting property with a hole mobility up to 0.0015 cm2V−1s−1. Notably, an OFET with a thin film of BDFTM is successfully utilized for highly sensitive and selective detection of H2S gas (down to ppb levels).

Self‐assembled core‐shell structured organic nanofibers fabricated by single‐nozzle electrospinning for highly sensitive ammonia sensors

“…Several remarkable strategies have been employed to enhance the sensing performance of OSC‐based chemical sensors such as designing novel molecular structures, adding specific receptors on OSCs film, and modifying the film thicknesses . In addition, one‐dimensional (1D) materials with unique nanostructure (nanofiber, nanobelt, and nanotube) are suitable for low‐concentration detection, which offer high sensitivity and fast response time for chemical sensors because of the large surface‐to‐volume ratios in 1D materials.…”

“…31 Several remarkable strategies have been employed to enhance the sensing performance of OSC-based chemical sensors such as designing novel molecular structures, adding specific receptors on OSCs film, and modifying the film thicknesses. [32][33][34][35][36][37] In addition, one-dimensional (1D) materials with unique nanostructure (nanofiber, nanobelt, and nanotube) are suitable for low-concentration detection, which offer high sensitivity and fast response time for chemical sensors because of the large surface-to-volume ratios in 1D materials. Numerous synthetic methods have been developed to prepare 1D structured nanofibers of which electrospinning is a simple, fast, and cost-effective approach to fabricate nanowire materials by electrostatic stretching.…”

Rational Design of Multiple-Stimulus-Responsive Materials via Supramolecular Self-Assembly

“…the HOMO−LUMO energy level implies that the PBA supramolecular material shows electron injection capabilities. 11,34 ■ CONCLUSION In this paper, we employed a supramolecular self-assembly strategy to build stimulus-responsive materials that contain both pH-and photoresponsive properties. Furthermore, we use a SAS strategy to guide and construct supramolecular materials with various morphologic characteristics.…”

Orientation‐Controlled 2D Anisotropic and Isotropic Photon Transport in Co‐crystal Polymorph Microplates

“…[28] More interestingly, the propagation loss of D1 is much smaller than those of D2 and D3, indicating an obviously 2D anisotropic transmission behavior, which is very different from the previous research results. [5,7,11,12] For the active waveguides, the major loss mechanisms include the substrate coupling loss (a s ) and the re-absorption loss (a r ). [29] The former depending on the relative refractive indexes between the substrate and microplate makes no difference to the distinct transport directions.…”

“…Conversely, if the molecular TDM are normal to the polarization, the photons would not interact with the molecular dipoles, leading to no re-absorption. However, to date, as-reported organic active 2D crystals still mainly display isotropic photon transport behaviors, [11] although a few suspected asymmetrical phenomena have been observed. [5,12] This is because most of organic 2D crystals adopt the inclined or perpendicular TDM orientations rather than the horizontal orientation, which makes the strengths of photon-dipole interaction along all 2D directions very close, and thus nearly the same re-absorption losses.…”