Comparative study of the optical,electrochemical, electrolumiscent,and photovoltaic properties of dendritic pendants modified poly(p‐phenylene vinylene)s

In this study, the optical, electrochemical, electrolumiscent, and photovoltaic properties of a series of poly(p‐phenylene vinylene) (PPV) derivatives bearing different dendritic pendants, poly{2‐3′,5′‐bis(2″‐ethylhexyloxy)benzyloxy]‐1,4‐phenylenevinylene} (BE‐PPV), poly{2‐2′,5′‐bis(3″,7″‐dimethyl)octyloxy]‐1,4‐phenylenevinylene} (BD‐PPV), poly2‐methoxy‐5‐(2′‐ethylhexyloxy)‐1,4‐phenylenevinylene] (MEH‐PPV), poly{2‐3′,5′‐bis(2″‐ethylhexyloxy)benzyloxy]‐1,4‐phenylenevinylene}‐co‐poly2‐methoxy‐5‐(2′‐ethylhexyloxy)‐1,4‐phenylenevinylene] (BE‐co‐MEH‐PPV), and poly{2‐2′,5′‐bis(3″,7″‐dimethyl)octyloxy]‐1,4‐phenylenevinylene}‐co‐poly2‐methoxy‐5‐(3′,7′‐dimethyloctyloxy)‐1,4‐phenylenevinylene] (BD‐co‐MDMO‐PPV), were investigated. The steric pendants strongly affect the absorption spectra, photoluminescence (PL) sepctra, the onset oxidation/reduction potentials, and further affect the electrolumiscent and photovoltaic properties. Copolymerization can reduce the steric effect and improve the electrolumiscent and photovoltaic properties. The brightness of light‐emitting diodes base on copolymer BE‐co‐MEH‐PPV and BD‐co‐MDMO‐PPV reached 3988 and 3864 cd/m², respectively, much higher than that based on homopolymer BE‐PPV (523 cd/m²) and BD‐PPV (333 cd/m²), also higher than that based on MEH‐PPV (3788 cd/m²). The power conversion efficiency (PCE) of solar cells based on BE‐co‐MEH‐PPV and BD‐co‐MDMO‐PPV reached 1.41, 0.76%, respectively, much higher than that based on BE‐PPV (0.24%) and BD‐PPV (0.14%). Copyright © 2010 John Wiley & Sons, Ltd.