Enhanced Light Absorption in Fluorinated Ternary Small-Molecule Photovoltaics

被引：32

作者：

Eastham, Nicholas D. ^{[1
,2
]}

Dudnik, Alexander S. ^{[1
,2
]}

Harutyunyan, Boris ^{[2
,3
]}

Aldrich, Thomas J. ^{[1
,2
]}

Leonardi, Matthew J. ^{[1
,2
]}

Manley, Eric F. ^{[1
,2
,5
]}

Butler, Melanie R. ^{[1
,2
]}

Harschneck, Tobias ^{[1
,2
]}

Ratner, Mark A. ^{[1
,2
]}

Chen, Lin X. ^{[1
,2
,5
]}

Bedzyk, Michael J. ^{[2
,3
,4
]}

Melkonyan, Ferdinand S. ^{[1
,2
]}

Facchetti, Antonio ^{[1
,2
]}

Chang, Robert P. H. ^{[2
,4
]}

Marks, Tobin J. ^{[1
,2
,4
]}

机构：

[1] Northwestern Univ, Mat Res Ctr, Dept Chem, 2145 Sheridan Rd, Evanston, IL 60208 USA

[2] Northwestern Univ, Argonne Northwestern Solar Energy Res Ctr, 2145 Sheridan Rd, Evanston, IL 60208 USA

[3] Northwestern Univ, Dept Phys & Astron, 2145 Sheridan Rd, Evanston, IL 60208 USA

[4] Northwestern Univ, Dept Mat Sci & Engn, 2145 Sheridan Rd, Evanston, IL 60208 USA

[5] Argonne Natl Lab, Chem Sci & Engn Div, 9700 South Cass Ave, Lemont, IL 60439 USA

来源：

ACS ENERGY LETTERS | 2017年 / 2卷 / 07期

关键词：

ORGANIC SOLAR-CELLS; OPEN-CIRCUIT VOLTAGE; POLYMER; PERFORMANCE; DONOR; EFFICIENCY; ENERGY; MORPHOLOGY; FILMS; CRYSTALLINITY;

D O I：

10.1021/acsenergylett.7b00486

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Using small-molecule donor (SMD) semiconductors in organic photovoltaics (OPVs) has historically afforded lower power conversion efficiencies (PCEs) than their polymeric counterparts. The PCE difference is attributed to shorter conjugated backbones, resulting in reduced intermolecular interactions. Here, a new pair of SMDs is synthesized based on the diketopyrrolopyrrole-benzodithiophene-diketopyrrolopyrrole (BDT-DPP2) skeleton but having fluorinated and fluorine-free aromatic side-chain substituents. Ternary OPVs having varied ratios of the two SMDs with PC61BM as the acceptor exhibit tunable open-circuit voltages (V(oc)s) between 0.833 and 0.944 V due to a fluorination-induced shift in energy levels and the electronic "alloy" formed from the miscibility of the two SMDs. A 15% increase in PCE is observed at the optimal ternary SMD ratio, with the short-circuit current density (J(sc)) significantly increased to 9.18 mA/cm(2). The origin of J(sc) enhancement is analyzed via charge generation, transport, and diffuse reflectance measurements, and is attributed to increased optical absorption arising from a maximum in film crystallinity at this SMD ratio, observed by grazing incidence wide-angle X-ray scattering.

引用

页码：1690 / 1697

页数：8

共 64 条

[11] Substantial photovoltaic response and morphology tuning in benzo[ 1,2-b: 6,5-b']-dithiophene (bBDT) molecular donors [J].