A new synthesis of large polyaromatic hydrocarbons (PAHs) with low Clar sextets is reported (see figure). The synthetic protocol involves starting bis(biaryl)diynes, which undergo initial PtCl2‐catalyzed aromatizations, and subsequent 2,3‐dichloro‐5,6‐dicyano benzoquinone (DDQ) oxidation.

A new synthesis of large PAHs with low Clar sextets was developed. This synthesis involves initial bis(biaryl)acetylene 1, which undergoes initial ICl-aromatization and a subsequent Mizoroki-Heck coupling reaction to give dibenzochrysene derivative 3 that can be transformed into planar PAHs 4 using DDQ-oxidation.

We report the regiocontrolled syntheses of ethene-bridged para-phenylene oligomers in three distinct classes by using Pt(II)- and Ru(II)-catalyzed aromatization. This synthetic approach has been developed based on twofold aromatization of the 1-aryl-2-alkynylbenzene functionality, which proceeds by distinct regioselectivity for platinum and ruthenium catalysts. Variable-temperature NMR spectra provide evidence that large arrays of these oligomers are prone to twist from planarity. The UV/Vis and photoluminescence (PL) spectra as well as the band gaps of these regularly growing arrays show a pattern of extensive pi conjugation with increasing array sizes, except for in one instance.

Perfect absorbers (PAs) at near infrared allow various applications such as biosensors, nonlinear optics, color filters, thermal emitters and so on. These PAs, enabled by plasmonic resonance, are typically powerful and compact, but confront inherent challenges of narrow bandwidth, polarization dependence, and limited incident angles as well as requires using expensive lithographic process, which limit their practical applications and mass production. In this work, we demonstrate a non-resonant PA that is comprised of six continuous layers of magnesium fluoride (MgF2) and chromium (Cr) in turns. Our device absorbs more than 90% of light in a broad range of 900–1900 nm. In addition, such a planar design is lithography-free, certainly independent with polarization, and presents a further advantage of wide incidence up to 70°. The measured performance of our optimized PA agrees well with analytical calculations of transfer matrix method (TMM) and numerical simulations of finite element method, and can be readily implemented for practical applications.

Electromagnetic components are important for ultraviolet (UV) applications. However, due to the limitation in the materials’ intrinsic responses, there are fewer electromagnetic components in high-frequency regimes than in low-frequency ones. Conventional UV components manipulate the wavefront via geometric phase accumulation; thus, they are significantly bulky and inefficient. In this study, we demonstrate all-dielectric Huygens’ metasurface (ADHMS) at a near-ultraviolet (NUV) regime. The NUV-ADHMS is comprised of resonant titanium dioxide (TiO2) nanodisks, with the ultrathin thickness of the fifth wavelength. In addition, by modulating the diameter of the resonant TiO2 nanodisks, we can simultaneously excite and control both electric and magnetic dipoles, achieving a powerful wavefront engineering of the near-unity transmittance and a full range of the 2π phase coverage. Finally, we employed the NUV-ADHMS to bend a normal incident beam, demonstrating a deflection angle of 11° at a wavelength of 405 nm.