title: Band structure engineering via piezoelectric fields in strained anisotropic CdSe/CdS nanocrystals.
abstract: Strain in colloidal heteronanocrystals with non-centrosymmetric lattices presents a unique opportunity for controlling optoelectronic properties and adds a new degree of freedom to existing wavefunction engineering and doping paradigms. We synthesized wurtzite CdSe nanorods embedded in a thick CdS shell, hereby exploiting the large lattice mismatch between the two domains to generate a compressive strain of the CdSe core and a strong piezoelectric potential along its c-axis. Efficient charge separation results in an indirect ground-state transition with a lifetime of several microseconds, almost one order of magnitude longer than any other CdSe/CdS nanocrystal. Higher excited states recombine radiatively in the nanosecond time range, due to increasingly overlapping excited-state orbitals. k˙p calculations confirm the importance of the anisotropic shape and crystal structure in the buildup of the piezoelectric potential. Strain engineering thus presents an efficient approach to highly tunable single- and multiexciton interactions, driven by a dedicated core/shell nanocrystal design.
authors.affiliation: 1] Nanochemistry Department, Istituto Italiano di Tecnologia, via Morego 30, IT-16163 Genova, Italy [2] Department of Physics, University of Genoa, via Dodecaneso 33, IT-16146 Genova, Italy.
authors.forename: Sotirios
authors.initials: S
authors.lastname: Christodoulou
authors.affiliation: Departament de Quimica Fisica i Analitica, Universitat Jaume I, ES-12080 Castellón, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: Rajadell
authors.affiliation: Nanochemistry Department, Istituto Italiano di Tecnologia, via Morego 30, IT-16163 Genova, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Casu
authors.affiliation: Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca, via Cozzi 55, IT-20125 Milano, Italy.
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Vaccaro
authors.affiliation: Nanochemistry Department, Istituto Italiano di Tecnologia, via Morego 30, IT-16163 Genova, Italy.
authors.forename: Joel Q
authors.initials: JQ
authors.lastname: Grim
authors.affiliation: Nanochemistry Department, Istituto Italiano di Tecnologia, via Morego 30, IT-16163 Genova, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Genovese
authors.affiliation: Nanochemistry Department, Istituto Italiano di Tecnologia, via Morego 30, IT-16163 Genova, Italy.
authors.forename: Liberato
authors.initials: L
authors.lastname: Manna
authors.affiliation: Departament de Quimica Fisica i Analitica, Universitat Jaume I, ES-12080 Castellón, Spain.
authors.forename: Juan I
authors.identifier: 0000000169846424
authors.initials: JI
authors.lastname: Climente
authors.affiliation: Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca, via Cozzi 55, IT-20125 Milano, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Meinardi
authors.affiliation: IBM Research-Zurich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Rainò
authors.affiliation: IBM Research-Zurich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland.
authors.forename: Thilo
authors.initials: T
authors.lastname: Stöferle
authors.affiliation: IBM Research-Zurich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland.
authors.forename: Rainer F
authors.initials: RF
authors.lastname: Mahrt
authors.affiliation: Departament de Quimica Fisica i Analitica, Universitat Jaume I, ES-12080 Castellón, Spain.
authors.forename: Josep
authors.initials: J
authors.lastname: Planelles
authors.affiliation: Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca, via Cozzi 55, IT-20125 Milano, Italy.
authors.forename: Sergio
authors.initials: S
authors.lastname: Brovelli
authors.affiliation: Nanochemistry Department, Istituto Italiano di Tecnologia, via Morego 30, IT-16163 Genova, Italy.
authors.forename: Iwan
authors.initials: I
authors.lastname: Moreels