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methylidene]aminophenoxyhexylgbenzene-1,3-dicarboxylate -a novel A 2 diol monomer -and a series of new blocked isocyanates (B 3 monomers) were synthesized in high yield and their structures were confirmed. Using these monomers, different hyperbranched polyurethanes (HBPUs) containing azomethine and aryl-ether connectivities were prepared via an A 2 þ B 3 approach. All possible parameters were varied to study their effect on molecular weight build-up. The effects of concentrations of A 2 and B 3 and the A 2 : B 3 monomer ratio were well reflected in the molecular weight of the polymer. The structure of the B 3 monomer was also found to have a significant effect on the molecular weight. The polymers were characterized by Fourier transform infrared, proton nuclear magnetic resonance, gel permeation chromatography, differential scanning calorimetry, thermogravimetric analysis, wide-angle X-ray diffraction and impedance spectroscopy. All the polymers registered unusual sub-T g ; and they invariably underwent decomposition at three distinct stages with significantly improved thermal stability at initial stage. The ionic conductivity of HBPU increased remarkably upon doping with KI and I 2 . The dye-sensitized solar cell fabricated using this polymer as electrolyte yielded an overall conversion efficiency of 3.5% upon illumination with visible light.

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The photovoltaic parameters of dye sensitized solar cells (DSSCs) fabricated with and without fourth generation polyurethane dendrimers have been discussed.

An amine‐terminated hyperbranched poly(aryl‐ether‐urea) (HBPEU) was prepared from an AB2‐type blocked isocyanate monomer and then its end groups were modified into urea (M‐HBPEU) by reaction with phenyl isocyanate. Both of the polymers were doped with N3‐dye along with KI/I2 to work as efficient polymer electrolytes in nanocrystalline dye sensitized solar cell. The increment in the conductivity of doped HBPEU and doped M‐HBPEU was very significant and reached its value at 8.2 × 10−3 and 4.1 × 10−2 S/cm, respectively. The current–voltage (I–V) characteristics of these two doped polymers measured under simulated sunlight with AM 1.5 at 60 mW/cm2 generate photocurrent of 2.5 and 3.6 mA/cm2, together with a photo voltage of 690 and 750 mV, and fill factor of 0.55 and 0.61 yielding a overall energy conversion efficiency of 2.4% and 4.1%, respectively. These results suggest that M‐HBPEU show better cell performance and conductance properties than the HBPEU. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40408.

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