Title

Linker-Induced Anomalous Emission Of Organic-Molecule Conjugated Metal-Oxide Nanoparticles

Keywords

linker molecules; organic-molecule conjugated nanoparticles; photoluminescence; semiconductor nanostructures

Abstract

Semiconductor nanoparticles conjugated with organic- and dye-molecules to yield high efficiency visible photoluminescence (PL) hold great potential for many future technological applications. We show that folic acid (FA)-conjugated to nanosize TiO 2 and CeO 2 particles demonstrates a dramatic increase of photoemission intensity at wavelengths between 500 and 700 nm when derivatized using aminopropyl trimethoxysilane (APTMS) as spacer-linker molecules between the metal oxide and FA. Using density-functional theory (DFT) and time-dependent DFT calculations we demonstrate that the strong increase of the PL can be explained by electronic transitions between the titania surface oxygen vacancy (OV) states and the low-energy excited states of the FA/APTMS molecule anchored onto the surface oxygen bridge sites in close proximity to the OVs. We suggest this scenario to be a universal feature for a wide class of metal oxide nanoparticles, including nanoceria, possessing a similar band gap (∼3 eV) and with a large surface-vacancy-related density of electronic states. We demonstrate that the molecule-nanoparticle linker can play a crucial role in tuning the electronic and optical properties of nanosystems by bringing optically active parts of the molecule and of the surface close to each other. © 2012 American Chemical Society.

Publication Date

6-26-2012

Publication Title

ACS Nano

Volume

6

Issue

6

Number of Pages

4854-4863

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1021/nn301316j

Socpus ID

84862880261 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/84862880261

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