Understanding polycarbazole-based polymer:CdSe hybrid solar cells.
We report for the first time the fabrication and characterization of organic-inorganic bulk heterojunction (BHJ) hybrid solar cells made of poly[N-9″-hepta-decanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)] (PCDTBT) and pyridine-capped CdSe nanorods. By optimizing both CdSe loading and active layer film thickness, the power conversion efficiencies (PCEs) of PCDTBT:CdSe hybrid solar cells were able to reach 2%, with PCDTBT:CdSe devices displaying an open-circuit voltage (V(OC )) that is 35% higher than P3HT:CdSe devices due to the deeper HOMO level of PCDTBT polymer. The performance of PCDTBT:CdSe devices is limited by its morphology and also its lower LUMO energy offset compared to P3HT:CdSe devices. Hence, the performance of PCDTBT:CdSe solar cells could be further improved by modifying the morphology of the films and also by including an interlayer to generate a built-in voltage to encourage exciton dissociation. Our results suggest that PCDTBT could be a viable alternative to P3HT as an electron donor in hybrid BHJ solar cells for high photovoltage application.
School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore.
Jun Yan
JY
Lek
Yeng Ming
YM
Lam
Jacek
J
Niziol
Mateusz
M
Marzec
D002104:Cadmium / Q000737:chemistry; D002227:Carbazoles / Q000737:chemistry; D011211:Electric Power Supplies; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure; D011108:Polymers / Q000737:chemistry; D011725:Pyridines / Q000737:chemistry; D012643:Selenium / Q000737:chemistry; D012993:Solar Energy; D013830:Thiadiazoles / Q000737:chemistry
D002227:Carbazoles; D011108:Polymers; D011725:Pyridines; D013830:Thiadiazoles; D002104:Cadmium; C015700:benzo-1,2,3-thiadiazole; D012643:Selenium; C023666:pyridine