title: Molecular control of quantum-dot internal electric field and its application to CdSe-based solar cells.
abstract: Inorganic nanocrystals are attractive materials for solar-cell applications. However, the performance of such devices is often limited by an insufficient alignment of energy levels in the nanocrystals. Here, we report that by attaching two different molecules to a single quantum dot or nanocrystal one can induce electric fields large enough to significantly alter the electronic and optoelectronic properties of the quantum dot. This electric field is created within the nanocrystals owing to a mixture of amine- and thiol-anchor-group ligands. Examining the steady state as well as temporal evolution of the optical properties and the nuclear magnetic resonances of the nanocrystals we found that the first excitonic peak shifts as a function of the capping-layer composition. We also demonstrate that the use of a mixed-ligand-induced electric field markedly enhances the charge generation efficiency in layer-by-layer CdSe-nanocrystal-based solar cells, thus improving the overall cell efficiency.
authors: Zisapel Nano-electronics Centre, Department of Electrical Engineering, Technion-Israel Institute of Technology, Technion City, Haifa 32000, Israel.
authors: Nir
authors: N
authors: Yaacobi-Gross
authors: Michal
authors: M
authors: Soreni-Harari
authors: Marina
authors: M
authors: Zimin
authors: Shifi
authors: S
authors: Kababya
authors: Asher
authors: A
authors: Schmidt
authors: Nir
authors: N
authors: Tessler