Enhancing the power conversion efficiency of organic solar cells

Organic solar cells (OSCs) have significantly reduced the overall cost of solar energy system, making solar oriented devices universally clean and green energy source. However, to make OSCs more competitive in diverse photovoltaic (PV) technologies, it is essential to attain high efficiencies by analyzing novel materials and realizing optimal arrangements of donor-acceptor materials. In this paper, we attempt to show a terse depth insight of OSCs by investigating three novel architecture schemes with special emphasis on improving the power conversion efficiency. The materials include include i) poly (3-hexylthiophene):[(6,6)]-phenyl C61 butyric acid methyl ester (P3HT:PCBM), ii) thieno [3,4-b] thiophene-alt-benzodithiophene [6,6]:-phenyl-C61 butyric acid methyl ester (PTB7:PCBM), and iii) poly{4,4'-bis(2-ethylhexyl) dithieno [3,2-b:2',3'-d] silole-alt-5,6-difluoro-4,7-bis (4-hexylthiophen-2-yl)-2,1,3-benzothiadiazle): [6,6]-phenyl-C61 butyric acid methyl ester (PDTS-DTffBT:PCBM), respectively. Results show that the extracted performance parameters including short circuit current (J(SC))= 10.88 mA/m(2), open circuit voltage (V-oc)= 0.82 V, fill factor (FF) = 83.52 %, and efficiency (eta)= 7.49 % is highest for the second scheme among others. Different intermediate layers have also been analyzed with the objective to reduce the recombination losses and enhance the power conversion efficiency of the proposed cell. The impact of temperature on the overall eta is also presented and it is discovered that high temperature reduces the performance of the solar cell. Furthermore, the performance of the proposed structure is compared with various kinds of OSCs and it is found that our design exhibit highest efficiency. The achievement of high efficiencies in this work may accelerate the practical applications of OSCs.