Morphology Change and Improved Efficiency in Organic Photovoltaics via Hexa-peri-hexabenzocoronene Templates

作者：Dam Henk H; Sun Kuan; Hanssen Eric; White Jonathan M; Marszalek Tomasz; Pisula Wojciech; Czolk Jens; Ludwig Jens; Colsmann Alexander; Pfaff Marina; Gerthsen Dagmar; Wong Wallace W H^*; Jones David J

来源：ACS Applied Materials & Interfaces, 2014, 6(11): 8824-8835.

DOI：10.1021/am5015666

• organic solar cell
• morphology control
• template
• surface modification
• molecule diffusion

The morphology of the active layer in organic photovoltaics (OPVs) is of crucial importance as it greatly influences charge generation and transport. A templating interlayer between the electrode and the active layer can change active layer morphology and influence the domain orientation. A series of amphiphilic interface modifiers (IMs) combining a hydrophilic polyethylene-glycol (PEG) oligomer and a hydrophobic hexabenzocoronene (HBC) were designed to be soluble in PEDOT:PSS solutions, and surface accumulate on drying. These IMs are able to self-assemble in solution. When IMs are deposited on top of a poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) film, they induce a morphology change of the active layer consisting of discotic fluorenyl-substituted HBC (FHBC) and [6,6]-phenyl C-61-butyric acid methyl ester (PCBM). However, when only small amounts (0.2 wt %) of IMs are blended into PEDOT:PSS, a profound change of the active layer morphology is also observed. Morphology changes were monitored by grazing incidence wide-angle X-ray scattering (GIWAXS), transmission electron microscopy (TEM), TEM tomography, and low-energy high-angle angular dark-field scanning transmission electron microscopy (HAADF STEM). The interface modification resulted in a 20% enhancement of power conversion efficiency.

• 出版日期2014-6-11