Correlatio n betwee n the theoretical ch emical co ncept of electrophilicity index for fu llerene de rivatives as accept ors and op en-circuit voltage inpolymer-f ullerene s olar cells

Fullerene derivatives with in herent high electron affinity and being able to transport ch arges effectively introduce an intriguing acce ptor for organic solar cells. The p ower conv ersion efficiency (PCE) of the PSC s based on a blend of poly(۳-hexylthiophene) (P۳HT) as an electr on donor and PCBM, th e most popular fullere ne derivatives as acceptors , has reached over ۴% [۱]. To further imp rove the P CE, designing new fullerene accep tors has been in priority of many researchers’ surveys. PC E is directl y proportional to the sh ort-circuit c urrent (ISC) a nd the ope n-circuit voltage (VOC) [۲]. In a polymer-fullerene solar cell, merely a little improvement of ISC is possible while there are still several considerable paths for improving the V OC. Meanwhile, accordi ng to survey s, the efficiency of fullerene as an acceptor in solar cell d epends not only on its electron affinity in order to effectively absorb the electron from the adjacent donor molecule, but also on its resistance against electron back transfer to donor molecule (to prevent the losing process o f the resulted electron–hole pairs). In this respe ct, we propose a linear relationship based on e lectrophilicity index, w hich has been examin ed on three series of fullerene deriva tives already used in fa brication of polymer-fullerene solar cells.

کلیدواژه ها:

Organic solar c ells ، Fullerene ، Electrophylicity ، LUMO ، DFT ، Open-c ircuit voltage.