I'm master student. I do research on organic solar cell.My research is to get efficiency more than 10%. I had read about Clean Energy Project(CEP) by Harvard University article and news. As far as I know their project get 9.2% of efficiency. Important things that I read were:

1)The molecules with the most promising predictions feature a variety of structural designs, but three motifs appear repeatedly in our top candidates: benzothiadiazole,pyridinethiadazole and thienopyrrole.
2)molecules with quinoidal stabilization (i.e. containing thienothiophene) numbered 117. A significant fraction of our top molecules hence belongs to
the latest generation of OPVs.

My question:
1)What is quinoidal structure and their characteristic?
2)benzothiadiazole,pyridinethiadazole and thienopyrrole is a donor, so what acceptor I have to use if I use this material?

link : http://cleanenergy.harvard.edu/index.php?ira=about_solarscience&tipoContenido=sid ebar&sidebar=science