20-21 November 2014
National Centre for Synchrotron Science
Australia/Melbourne timezone
Save the date: User Meeting 2015 - 26-27 November

Unraveling the morphology of a novel, high-efficient polymer solar cell using synchrotron-based techniques

20 Nov 2014, 17:30
1h 30m
NCSS Exhibition Area ()

NCSS Exhibition Area

Australian Synchrotron 800 Blackburn Road Clayton VIC 3168
Board: 502


Mr Wenchao Huang (Monash University)


Organic solar cells are a next generation photovoltaic technology with the potential for a low cost of manufacturing and printing on flexible substrates. The efficiency of organic solar cells has increased rapidly, recently exceeding 9% efficiency. Understanding the morphology of the active layer of polymer based bulk heterojunction solar cells is necessary to further improve device performance. Here we comprehensively study the morphology of a novel electron donor polymer PBDTTT-EFT with efficiency of over 9%. The orientation and microstructure of the neat polymer films and in blend films with PC71BM are examined by using a combination of surface-sensitive near edge X-ray absorption fine structure (NEXAFS) spectroscopy from the soft X-ray beamline and bulk sensitive grazing incidence wide angle X-ray scattering (GIWAXS) collected at the SAXS/WAXS beamline. In the blend, a “face-on” orientation of PBDTTT-EFT is observed with π-π stacking normal to the substrate in the bulk of thin film, while a more “edge-on” orientation with side-chain-stacking normal to substrate is observed at the surface of the film. In organic solar cells, face-on structures enhance charge transport in the critical vertical direction. An edge-on orientation of PBDTTT at the hole extracting interface is not considered to be ideal for charge collection, but does not appear to adversely affect device performance. The additive 1,8-Diiodooctane is also used to improve the crystallization of PBDTTT-EFT and to control the aggregation of PC71BM.
Keywords or phrases (comma separated) Organic solar cells, morphology, GIWAXS, NEXAFS,

Primary author

Mr Wenchao Huang (Monash University)


Chris McNeill (Monash University) Eliot Gann (Australian Synchrotron)

Presentation Materials

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