A series of cyclometalated Ru(II) complexes with 2-arylbenzimidazoles antenna ligands bearing electron-donor/withdrawing substituents and anchoring 4,4′-dimethoxycarbonyl-2,2′-bipyridine have been prepared and their structure, optical and electrochemical properties have been studied. The...
Laser-induced
periodic surface structures (LIPSS) can be fabricated
in virtually all types of solid materials and show great promise for
efficient and scalable production of surface patterns with applications
in various fields from photonics to engineering. While the majority
of LIPSS manifest as modifications of the surface relief, in special
cases, laser impact can also lead to periodic modulation of the material
phase state. Here, we report on the fabrication of high-quality periodic
structures in the films of phase-change material Ge2Sb2Te5 (GST). Due to considerable contrast of the
refractive index of GST in its crystalline and amorphous states, the
fabricated structures provide strong spatial modulation of the optical
properties, which facilitates their applications. By changing the
excitation laser wavelength, we observe the scaling of the grating
period as well as transition between formation of different types
of LIPSS. We optimize the laser exposure routine to achieve large-scale
high-quality phase-change gratings with controllable period and demonstrate
their reversible tunability through intermediate amorphization steps.
Our results reveal the prospects of fast and rewritable fabrication
of high-quality periodic structures for photonics and can serve as
a guideline for further development of phase-change material-based
optical elements.
New metal-free sensitizers (IK 3-6), based on the thieno [2,3-b]indole ring system, bearing various aliphatic substituents at the nitrogen atom (electron-donating part), several thiophene units (π-bridge linker) and 2-cyanoacrylic acid (the electron-accepting and anchoring group) have been synthesized for application in dye-sensitized solar cells (DSSCs). The relationship between the IK dye structure and efficiency of the corresponding DSSC has been elucidated. Power conversion efficiency (PCE) up to 6.3% (short-circuit photocurrent density (JSC) 19.0 mA cm -2 , open-circuit voltage (VOC) 0.59 V, and fill factor (FF) 56.4%) were obtained for the DSSC, based on 2-cyano-, which proved to be a highly synthetic available compound, under simulated AM 1.5 G irradiation (100 mW cm -2 ), thus indicating that thieno [2,3-b]indole-based organic dyes are perspective candidates for DSSCs.
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