ABSTRACT
High refractive index polymers (HRIPs) have drawn attention for their optoelectronic applications and HRIPs with excellent transparency and facile preparation are highly demanded. Herein, sulfur-containing all organic HRIPs with refractive indices up to 1.8433 at 589 nm and excellent optical transparency even in one hundred micrometre scale in the visual and RI region as well as high weight-average molecular weights (up to 44500) are prepared by our developed organobase catalyzed polymerization of bromoalkynes and dithiophenols in yields up to 92%. Notably, the fabricated optical transmission waveguides using the resultant HRIP with the highest refractive index display a reduced propagation loss compared with that generated by the commercial material of SU-8. In addition, the tetraphenylethylene containing polymer not only exhibits a reduced propagation loss, but also is used to examine the uniformity and continuity of optical waveguides with naked eyes because of its aggregation-induced emission feature.
ABSTRACT
High-efficiency low-cost all-flexible microcavity semitransparent polymer solar cells (STPSCs) are comparatively studied in both fullerene- and nonfullerene-based systems with the structure strategy, employing polymer flexible one-dimensional photonic crystals (F-1DPCs), as well as indium tin oxide-free UV/ozone plasma-treated polymer/ultrathin metal and PEDOT:PSS transparent electrodes. Based on the reasonable optimization of electrical and optical characteristics in the device, the maximum power conversion efficiency with the use of polymer F-1DPCs can be greatly improved by 24-27% compared to the respective control devices. The improvement in JSC is comprehensively discussed, which is mainly ascribed to the enhancement of effective photon absorption in the device. Although color tunability of fullerene and nonfullerene all-flexible STPSCs can be easily achieved with the use of different photonic band gaps of polymer F-1DPCs, the CIE coordinates of nonfullerene STPSCs differ a lot from the original light source compared to the fullerene ones because of a high absorption coefficient in a narrow wavelength region. This work presents an easy and effective microcavity device strategy incorporated with different elements and demonstrates a new sketch of structure-absorption-performance relationships for fullerene- versus nonfullerene-based all-flexible STPSCs, which is compatible with low-cost roll-to-roll manufacturing and surely has a diversity of potential applications to better meet specific needs.
ABSTRACT
The C-H activation has been a hot research area in organic chemistry, and the most difficult one is the C(sp3)-H activation. Although the C-H activation has been introduced to the research of synthetic polymer chemistry, the polymerization developed based on C(sp3)-H activation is rarely reported, which will enrich the tools for the preparation of functional polymers. In this work, palladium/benzoic acid catalyzed polymerization of internal diynes and diols through C(sp3)-H activation was successfully established. Regio- and stereoregular functional poly(allylic ether)s with 100% E-isomers and high weight average molecular weights (Mw up to 33200) were prepared in excellent yield (98%). The reaction mechanism was unveiled with the assistance of density functional theory calculations. Furthermore, the thin films of polymers display high refractive indices and low optical dispersions. The polymer containing tetraphenylethene moiety displays the aggregation-enhanced emission feature and could be used to generate 2D fluorescent photopattern. Thus, this work not only establishes a powerful polymerization based on C(sp3)-H activation, but also furnishes functional polymers for diverse applications.
