Small-Size Effects on Electron Transfer in P3HT/InP Quantum Dots
Raavi, Sai Santosh Kumar
Gurzadyan, Gagik Grigorʹevich
Date of Issue2015-11-06
School of Physical and Mathematical Sciences
The charge carrier photogeneration yield in hybrid polymer/nanocrystal solar cells strongly depends on the interplay between charge transfer across quantum dot (QD) organic capping layers and quantum confinement effects related to the QD size. Here we combine femtosecond transient spectroscopy and density functional theory (DFT) calculations to improve the understanding of charge transfer dynamics at P3HT/InP QD heterointerfaces as a function of core size (2.5 vs 4.5 nm) and length of the surface ligands (oleylamine vs pyridine). We find that, for large core QDs, the polaron generation yield in P3HT is enhanced by efficient exciton dissociation and charge transfer, and is limited by the length of the ligands. Conversely, for smaller size QDs, electron injection from P3HT to InP cores becomes inefficient due to the unfavorable interfacial energetics, even with short pyridine ligands. Thus, we suggest that both QD surface ligand functionalization and core size should be optimized simultaneously for the design of high-performance hybrid nanocrystal/polymer solar cells.
The Journal of Physical Chemistry C
© 2015 American Chemical Society. This paper was published in The Journal of Physical Chemistry C and is made available as an electronic reprint (preprint) with permission of American Chemical Society. The published version is available at: [http://dx.doi.org/10.1021/acs.jpcc.5b09397]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law.