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arXiv · 1406.4468

The Effect of Cesium Carbonate on PCBM Aggregation in Films

William R. Lindemann·Wenjie Wang·Fadzai Fungura·Joseph Shinar·Ruth Shinar·David Vaknin
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Abstract

Surface-pressure isotherms, X-ray reflectivity and X-ray near-total reflection fluorescence were used to study the properties of 1-(3-methoxycarbonyl)propyl-1-phenyl[6,6]C$_{61}$ (PCBM) that was pre-mixed with cesium carbonate and spread as a film at the air-water interface. The pre-mixed PCBM with cesium carbonate demonstrated a strikingly strong effect on the organization of the film. Whereas films formed from pure PCBM solution were rough due to strong inter-molecular interactions, the films formed from the mixture were much smoother. This indicates that the cesium carbonate moderates the inter-molecular interactions among PCBM molecules, hinting that the cesium diffusion observed in inverted organic photovoltaics and the likely ensuing ionic Cs-PCBM interaction decreases aggregation tendency of PCBM. This implies that the use of cesium salts affects the morphology of the organic layer and consequently improves the efficiency of these devices.

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William R. Lindemann, Wenjie Wang, Fadzai Fungura, Joseph Shinar, Ruth Shinar, David Vaknin. 2014-11-14. The Effect of Cesium Carbonate on PCBM Aggregation in Films. https://doi.org/10.1063/1.4901444

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