Control of the active layer nanomorphology by using co-additives towards high-performance bulk heterojunction solar cells

In this work, two high boiling-point solvents (1-chloronaphthalene (CN) and 1,8-diiodooctane (DIO)) were utilized as co-additives in ortho-dichlorobenzene (ODCB) and chlorobenzene (CB) solutions to fine tune the donor and acceptor domains in the bulk heterojunction (BHJ) of poly(benzo[1,2-b:4,5-b\u2032]dithiophene-alt-thieno[3,4-c]pyrrole-4,6-dione) (PBDTTPD) and fullerene derivatives. A power conversion efficiency of 7.1% and a fill factor up to 70% were obtained for solar cells with active area of 1 cm2 when using [6,6]-phenyl C61-butyric acid methyl ester (PC60BM) as acceptor, suggesting that an optimized morphology was achieved.Peer reviewed: YesNRC publication: Ye

A Thieno[3,4-c]pyrrole-4,6-dione-based copolymer for efficient solar cells

Peer reviewed: YesNRC publication: Ye

Effect of mixed solvents on PCDTBT:PC 70BM based solar cells

We investigated the effect of solvents on the morphology, charge transport and device performance of poly[N-9\u2033-hepta-decanyl-2,7-carbazole-alt-5,5- (4\u2032,7\u2032-di-2-thienyl-2\u2032,1\u2032,3\u2032-benzothiadiazole)] (PCDTBT) and [6,6]-phenyl C71-butyric acid methyl ester (PC 70BM) based solar cells. To carry out this investigation, chloroform and 1,2-dichlorobenzene were chosen as good solvents of the two compounds. Films prepared with chloroform exhibit larger domains than those prepared with 1,2-dichlorobenzene and their size increases with the amount of PC 70BM. Fine tuning of the domain size was realized by using a solvent of mixed chloroform and 1,2-dichlorobenzene. At a mixing ratio of 50%:50%, a power conversion efficiency of 6.1% was achieved on PCDTBT:PC 70BM (1:3) devices with an active area of 1 cm 2, under air mass 1.5 global (AM 1.5 G) irradiation at 100 mW/cm 2. \ua9 2011 Published by Elsevier B.V. All rights reserved.Peer reviewed: YesNRC publication: Ye

Bulk heterojunction solar cells using thieno[3,4- c ]pyrrole-4,6-dione and dithieno[3,2- b:2\u2032,3\u2032- d ]silole copolymer with a power conversion efficiency of 7.3%

A new alternating copolymer of dithienosilole and thienopyrrole-4,6-dione (PDTSTPD) possesses both a low optical bandgap (1.73 eV) and a deep highest occupied molecular orbital energy level (5.57 eV). The introduction of branched alkyl chains to the dithienosilole unit was found to be critical for the improvement of the polymer solubility. When blended with PC71BM, PDTSTPD exhibited a power conversion efficiency of 7.3% on the photovoltaic devices with an active area of 1 cm2. \ua9 2011 American Chemical Society.Peer reviewed: YesNRC publication: Ye