title: Doping ZnO with Water/Alcohol-Soluble Small Molecules as Electron Transport Layers for Inverted Polymer Solar Cells.
abstract: By doping ZnO with porphyrin small molecules (FNEZnP-OE and FNEZnP-T) as cathode electron transport layers (ETLs), the inverted polymer solar cells (i-PSC) with PTB7:PC71BM (PTB7: polythieno[3,4-b]-thiophene-co-benzodithiophene, PC71BM:[6, 6]-phenyl-C71-butyric acid methyl ester) as the active materials exhibit enhanced device performance. While the power conversion efficiency (PCE) of the PSCs with pure ZnO ETL is 7.52%, that of the devices with FNEZnP-T-doped ZnO ETL shows a slightly improved PCE of 8.09%, and that of the PSCs with FNEZnP-OE-doped ZnO ETL is further enhanced up to 9.24% with an over 20% improvement compared to that with pure ZnO ETL. The better performance is contributed by the better interfacial contact and reduced work function induced by 9,9-bis(30-(N,N-dimethylamino)propyl)-2,7-fluorenes and 3,4-bis(2-(2-methoxy-ethoxy)-ethoxy)-phenyls in the porphyrin small molecules. More importantly, the PCE is still higher than 8% even when the thickness of FNEZnP-OE-doped ZnO ETL is up to 110 nm, which are important criteria for eventually making organic photovoltaic modules with roll-to-roll coat processing.
authors.affiliation: State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology , 381 Wushan Road, Guangzhou 510640, China.
authors.forename: Chang
authors.initials: C
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology , 381 Wushan Road, Guangzhou 510640, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology , 381 Wushan Road, Guangzhou 510640, China.
authors.forename: Liangang
authors.initials: L
authors.lastname: Xiao
authors.affiliation: State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology , 381 Wushan Road, Guangzhou 510640, China.
authors.forename: Xiaobin
authors.initials: X
authors.lastname: Peng
authors.affiliation: State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology , 381 Wushan Road, Guangzhou 510640, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Cao
keywords: ZnO; interlayer; inverted solar cells; porphyrin; small molecule