PHOTOVOLTAIC STRUCTURES BASED ON BIOLOGIC/POLYMERIC SEMICONDUCTING THIN FILMS

Photovoltaic cells based on biologic (Chlorophyll-a, Chl-a) and polymeric (poly(3-hexylthiophene-2,5-diyl), P3HT, and [6,6]-phenyl-C61 butyric acid methyl ester, PCBM) thin films were prepared and characterized. Two types of structures were fabricated, either with a bi-layer Chl-a/P3HT:PCBM(1:1, wt.%) or a single layer Chl-a:P3HT:PCBM(10:1:1, wt. %) design, the photoactive layers being deposited by spin coating technique. Their optical and photovoltaic properties were analyzed and compared with those of a bulk heterojunction P3HT:PCBM(1:1, wt.%) cell Similar values were found for fill factor and open circuit voltage but an enlarged region of spectral response was observed in the case of the cells containing Chl-a. The short-circuit current measured in the case of Chl-a/P3HT:PCBM(1:1, wt.%) and Chl-a:P3HT:PCBM(10:1:1, wt.%) based cells was smaller than in the case of P3HT:PCBM(1:1, wt.%) cell.