Synthesis and characterization of novel phthalazine based push-pull heterocyclic systems for DSSCs

Research on renewable energy sources have been expanding considerably in order to decrease the consumption of fossil fuels and therefore reduce global warming and environmental pollution. Solar cells based on organic dye sensitizers (DSSCs) is a photovoltaic device that have been extensively studied due to their high incident solar light-to-electricity conversion efficiency and low cost of production. In the interest of achieving chromophores with high performance for DSSCs, wide-ranging research has been conducted on structural modifications of the sensitizing dyes. One of the approaches is the tuning the pi-bridge with auxiliary electron donor/acceptor groups, such as electron-rich thiophene and furan heterocycles linked to the electron-deficient phthalazine ring substituted with appropriate acceptor groups, which are promising candidates among such push-pull systems. As part of an on-going research to develop efficient donor - pi-spacer - acceptor heterocyclic systems for several optoelectronic applications we report the synthesis and characterization of phthalazine derivatives functionalized with cyanoacetic or rhodanine-3-acetic acid as anchoring groups and (hetero)aryl groups as donor/pi-spacers. The experimental results indicate that, these compounds could have potential application as NLO chromophores as well as sensitizers for DSSCs.