ABSTRACT
Hyperbranched poly(aryl-ether-urea)s with phenyl, N,N-dimethylamino ethyl and polyethylene oxide end-groups linked through urethane group – HBPEU-1, HBPEU-2 and HBPEU-3 respectively – were synthesized from an AB2-type blocked isocyanate monomer and characterized by FT-IR, 1H-NMR, SEC-MALLS, TGA and DSC techniques. The molecular weight of the polymers were found to be ranged from 4.9 × 103 − 1.96 × 104 g/mol. The TGA results showed that the polymers decompose between 175°C – 220°C. In the DSC curves, HBPEU-1 and HBPEU-3 showed Tg at 160°C and 53°C respectively, whereas HBPEU-2 did not showed clear Tg. All the three polymers were converted into polymer electrolytes by doping with LiI/I2. The doped polymers showed remarkably high ionic conductivity, up to 222 – 277 times compared to the un-doped polymers and the highest conductivity was observed with doped HBPEU-2. The TiO2 based dye-sensitized solar cells (DSSCs) were fabricated using the doped polymer electrolytes and their performance was tested; HBPEU-2 showed good performance by yielding energy conversion efficiency (η) of 4.5%.
Acknowledgment
The authors (S.S and A.S.N) gratefully acknowledge CSIR, India, for financial support under a Scheme No.02(0100)/12/EMR-II. Dt.31.10.2012.