Two phenazine donor–acceptor-conjugated copolymers (P1 and P2) with the same polymer backbone but different anchoring positions of alkoxy chain on the phenazine unit were investigated to identify the effect of changing the position of alkoxy chains on their optical, electrochemical, blend film morphology, and photovoltaic properties. Although the optical absorption and frontier orbital energy levels were insensitive to the position of alkoxy chains, the film morphologies and photovoltaic performances changed significantly. P1/PC₇₁BM blend film showed the formation of phase separation with large coarse aggregates, whereas P2/PC₇₁BM blend film was homogeneous and smooth. Accordingly, power conversion efficiency (PCE) of photovoltaic devices increased from 1.50% for P1 to 2.54% for P2. In addition, the PCE of the polymer solar cell based on P2/PC₇₁BM blend film could be further improved to 3.49% by using solvent vapor annealing treatment. These results clearly revealed that tuning the side-chain position could be an effective way to adjust the morphology of the active layer and the efficiency of the photovoltaic device. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2910–2918

Water-soluble, meta- and para-linked poly(arylene ethynylene)s containing L-aspartic acid-functionalized fluorene units (P1 and P2) and their model compounds (M1 and M2) have been synthesized, and their photophysical properties and fluorescent sensing properties were investigated in aqueous solution. P1 and M1 with the meta-linkage show blue-shifted absorption and emission spectra, and decreased photoluminescence quantum yields compared with those of P2 and M2 with para-linkage. Their absorption and fluorescence spectra are pH dependent perhaps due to the aggregation of the polymer chains at low pH values. In buffer solutions, both polymers and their model compounds exhibit the excellent selectivity and sensitivity to Hg²⁺ over other common metal ions. Furthermore, the quenching constant and detection limit of P1 are determined to be 1.04 × 10⁷ M⁻¹ and 10 nM, and show the higher sensitivity compared to P2. Further comparison of their model compounds reveal that the sensitivity and quenching efficiency of M1 is also higher than that of M2, indicating that the meta-linkage pattern plays a key role in improving their Hg²⁺ ion sensing properties. In addition, both meta- and para-linked polymers exhibit the higher quenching efficiency than their model compounds due to the amplified fluorescence response of conjugated polymer. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

A series of star-like dopant/host single-polymer systems with a D-A type star-shaped orange core and three blue polyfluorene arms were designed and synthesized. Through tuning the doping concentration of the orange core and thermal annealing treatment of white polymer light-emitting diodes based on them, highly efficient white electroluminescence has been achieved. A typical single-layer device (ITO/PEDOT:PSS/polymer/Ca/Al) realized pure white emission with a luminous efficiency of 16.62 cd A⁻¹, an external quantum efficiency of 6.28% and CIE coordinates of (0.33, 0.36) for S-WP-002TPB3 containing 0.02 mol % orange core. The high efficiency of the devices could be mainly attributed to the suppressed concentration quenching of the dopant units, more efficient energy transfer from polymer host to orange dopant and thermal annealing-induced α-phase polyfluorene (PF) self-dopant in amorphous PF host. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

A series of novel arylene ether polymers (P5F-BCzVFs) containing both pentafluorene (5F) and distyrylarylene derivative (BCzVF) units in the side chains for efficient pure blue light emission were prepared by a facile, metal-free condensation polymerization. The emission spectra indicated that color tuning could be achieved through efficient Förster energy transfer from the deep-blue 5F host to the pure-blue BCzVF dopant. Single-layer polymer light-emitting diodes (PLEDs) based on P5F-BCzVFs (ITO/(PEDOT:PSS)/polymer/Ca/Al) exhibited voltage-independent and stable pure blue emission with a Commission International de L'Eclairage (CIE) coordinate of (0.15, 0.15), a maximum brightness of 3576 cd/m², and a maximum luminous efficiencies of 2.15 cd/A, respectively. As most polymers with dopant-host systems, the luminous efficiencies of all P5F-BCzVFs surpassed that of the host-only polymer (P5F), due to the energy transfer and charge trapping from the host to the dopant. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011