Flexible and Transparent Oligothiophene-o-Carborane-Containing Hybrid Films for Nonlinear Optical Limiting Based on Efficient Two-Photon Absorption

Abstract

Structure–property relationship for fluorophores with favorable nonlinear optical (NLO) properties are promising topics in organic chemistry and material science. Herein, a series of terthiophene-o-carborane dyads and triads covalently linked with different end-capping styles were readily synthesized and comprehensively investigated. Quantitative values of the crystal and packing structures, photophysical parameters including aggregation-induced emission (AIE) and two-photon absorption (2PA) were provided. Significant impact of carborane unit for introducing the AIE characteristic has been investigated in contrast to the parent oligothiophene. All the obtained fluorophores exhibit maximum absorption around 370 nm in THF and emit bright reddish photoluminscence with absolute fluorescence quantum yields above 16% in solid states. Intramolecular charge communication between oligothiophene and carborane plays important roles in the related NLO properties. These results are supported well by the time-dependent DFT theoretical calculations. Effective 2PA cross sections (δ2PA = 95–355 GM@650 nm) and transition dipole moments of the derivatives are variable for different end-capping styles. Their potential applications as optical limiting materials based on the 2PA mechanism in solutions and doped PDMS films were further evaluated. Taken together, this work provides an understanding of their structure–property relationship, and flexible PDMS films as outstanding candidates for practical applications in optical limiting.

Resonance-Enhanced Two-Photon Absorption and Optical Power Limiting Properties of Three-Dimensional Perylene Bisimide Derivatives

“…Among many nonlinear optical (NLO) characteristics of functional materials, two-photon absorption (2PA) has attracted extensive attention during the past few decades. − The quadratic dependence of its absorption efficiency on the laser-input intensity allows spatial confinement of the excitation. This vital property has been exploited in interdisciplinary applications including two-photon scanning microscopy, photodynamic therapy, optical power limiting (OPL), three-dimensional (3D) microfabrication, optical data storage, etc. − Theoretically, as an important parameter of 2PA, the magnitude of the 2PA cross section (δ 2PA ) was apparently affected by the donor–acceptor strength, effective conjugation length, planarity of the π-skeleton, etc. − Recently, a large number of conjugated chromophores were designed and synthesized to achieve better δ 2PA values with great success based on the multipolar and/or multibranching strategy. , Regardless of the enormous research efforts that have been focused on designing better and more efficient 2PA materials, detailed understanding about the stereo effect of molecular entities on the NLO properties is still limited.…”

Stealth Luminescent Organic Nanoparticles Made from Quadrupolar Dyes for Two-Photon Bioimaging: Effect of End-Groups and Core

“…The 2PA spectra are shown in Figure 4 . As expected from the quadrupolar nature of the Q 2 – Q 4 dyes, the lowest energy 1P allowed excited state is almost 2P forbidden, whereas an intense 2PA band is observed at higher energy corresponding to an almost 1P forbidden excited state [ 12 , 41 , 42 , 43 , 44 , 45 ]. Interestingly, dye Q 1 also shows a strong 2PA band located around 750 nm corresponding to a 1P allowed excited state.…”

Construction of MXene/PDMS‐Based Triboelectric Nanogenerators for High‐Performance Cathodic Protection

“…[50] It can be presumed that the compound of MXene conductive filler and PDMS is a feasible method to increase the TENG output performance. [47,51,52] Herein, we prepare PDMS film coated with MXene particles through blade-coating and spray. Avoiding the problem of poor dispersion caused by mechanical mixing, spray could construct stable combination and the appearance of micro-uneven structure was fabricated on the surface.…”