title: Tuning the Lattice Parameter of InxZnyP for Highly Luminescent Lattice-Matched Core/Shell Quantum Dots.
abstract: Colloidal quantum dots (QDs) show great promise as LED phosphors due to their tunable narrow-band emission and ability to produce high-quality white light. Currently, the most suitable QDs for lighting applications are based on cadmium, which presents a toxicity problem for consumer applications. The most promising cadmium-free candidate QDs are based on InP, but their quality lags much behind that of cadmium based QDs. This is not only because the synthesis of InP QDs is more challenging than that of Cd-based QDs, but also because the large lattice parameter of InP makes it difficult to grow an epitaxial, defect-free shell on top of such material. Here, we propose a viable approach to overcome this problem by alloying InP nanocrystals with Zn(2+) ions, which enables the synthesis of InxZnyP alloy QDs having lattice constant that can be tuned from 5.93 Å (pure InP QDs) down to 5.39 Å by simply varying the concentration of the Zn precursor. This lattice engineering allows for subsequent strain-free, epitaxial growth of a ZnSezS1-z shell with lattice parameters matching that of the core. We demonstrate, for a wide range of core and shell compositions (i.e., varying x, y, and z), that the photoluminescence quantum yield is maximal (up to 60%) when lattice mismatch is minimal.
authors.affiliation: Optoelectronic Materials Section, Faculty of Applied Sciences, Delft University of Technology , Julianalaan 136, 2628 BL Delft, The Netherlands.
authors.forename: Francesca
authors.initials: F
authors.lastname: Pietra
authors.affiliation: Department of Nanochemistry, Istituto Italiano di Tecnologia (IIT) , via Morego, 30, 16163 Genova, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: De Trizio
authors.affiliation: Optoelectronic Materials Section, Faculty of Applied Sciences, Delft University of Technology , Julianalaan 136, 2628 BL Delft, The Netherlands.
authors.forename: Anne W
authors.initials: AW
authors.lastname: Hoekstra
authors.affiliation: Optoelectronic Materials Section, Faculty of Applied Sciences, Delft University of Technology , Julianalaan 136, 2628 BL Delft, The Netherlands.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Renaud
authors.affiliation: Department of Nanochemistry, Istituto Italiano di Tecnologia (IIT) , via Morego, 30, 16163 Genova, Italy.
authors.forename: Mirko
authors.initials: M
authors.lastname: Prato
authors.affiliation: Optoelectronic Materials Section, Faculty of Applied Sciences, Delft University of Technology , Julianalaan 136, 2628 BL Delft, The Netherlands.
authors.forename: Ferdinand C
authors.initials: FC
authors.lastname: Grozema
authors.affiliation: Philips Research Laboratories , High Tech Campus 4, 5656 AE Eindhoven, The Netherlands.|Soft Condensed Matter, Debye Institute, Utrecht University , Princetonplein 5, 3584 CC Utrecht, The Netherlands.
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Baesjou
authors.affiliation: Philips Research Laboratories , High Tech Campus 4, 5656 AE Eindhoven, The Netherlands.
authors.forename: Rolf
authors.initials: R
authors.lastname: Koole
authors.affiliation: Department of Nanochemistry, Istituto Italiano di Tecnologia (IIT) , via Morego, 30, 16163 Genova, Italy.|Kavli Institute of Nanoscience, Delft University of Technology , Lorentzweg 1, 2628 CJ Delft, The Netherlands.
authors.forename: Liberato
authors.initials: L
authors.lastname: Manna
authors.affiliation: Optoelectronic Materials Section, Faculty of Applied Sciences, Delft University of Technology , Julianalaan 136, 2628 BL Delft, The Netherlands.
authors.forename: Arjan J
authors.initials: AJ
authors.lastname: Houtepen
keywords: In(Zn)P; alloy nanocrystals; core/shell heterostructures; lattice mismatch; phosphors; quantum dots