Directional charge separation in isolated organic semiconductor crystalline nanowires

Journal Article · Thu Feb 25 00:00:00 EST 2016 · Nature Communications

DOI:https://doi.org/10.1038/ncomms10629· OSTI ID:1361622

Labastide, J. A. ^[1]; Thompson, H. B. ^[1]; Marques, S. R. ^[1]; Colella, N. S. ^[1]; Briseno, A. L. ^[1]; Barnes, M. D. ^[1]

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1. Univ. of Massachusetts, Amherst, MA (United States)

One of the fundamental design paradigms in organic photovoltaic device engineering is based on the idea that charge separation is an extrinsically driven process requiring an interface for exciton fission. This idea has driven an enormous materials science engineering effort focused on construction of domain sizes commensurate with a nominal exciton diffusion length of order 10 nm. Here, we show that polarized optical excitation of isolated pristine crystalline nanowires of a small molecule n-type organic semiconductor, 7,8,15,16-tetraazaterrylene, generates a significant population of charge-separated polaron pairs along the π-stacking direction. Charge separation was signalled by pronounced power-law photoluminescence decay polarized along the same axis. In the transverse direction, we observed exponential decay associated with excitons localized on individual monomers. We propose that this effect derives from an intrinsic directional charge-transfer interaction that can ultimately be programmed by molecular packing geometry.

• Research Organization: Univ. of Massachusetts, Amherst, MA (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: FG02-05ER15695
• OSTI ID: 1361622
• Journal Information: Nature Communications, Vol. 7; ISSN 2041-1723
• Publisher: Nature Publishing Group
• Country of Publication: United States
• Language: English

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY