skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Linker-Induced Anomalous Emission of Organic-Molecule Conjugated Metal-Oxide Nanoparticles

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 TiO2 and CeO2 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.

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
1177367
Report Number(s):
PNNL-SA-91297
46400; KP1704020
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
ACS Nano, 6(6):4854-4863
Additional Journal Information:
Journal Name: ACS Nano, 6(6):4854-4863
Country of Publication:
United States
Language:
English
Subject:
Environmental Molecular Sciences Laboratory

Citation Formats

Turkowski, Volodymyr, Babu, Suresh, Le, Duy, Kumar, Amit, Haldar, Manas K., Wagh, Anil V., Hu, Zhongjian, Karakoti, Ajay S., Gesquiere, Andre J., Law, Benedict, Mallik, Sanku, Rahman, Talat S., Leuenberger, Michael N., and Seal, Sudipta. Linker-Induced Anomalous Emission of Organic-Molecule Conjugated Metal-Oxide Nanoparticles. United States: N. p., 2012. Web. doi:10.1021/nn301316j.
Turkowski, Volodymyr, Babu, Suresh, Le, Duy, Kumar, Amit, Haldar, Manas K., Wagh, Anil V., Hu, Zhongjian, Karakoti, Ajay S., Gesquiere, Andre J., Law, Benedict, Mallik, Sanku, Rahman, Talat S., Leuenberger, Michael N., & Seal, Sudipta. Linker-Induced Anomalous Emission of Organic-Molecule Conjugated Metal-Oxide Nanoparticles. United States. doi:10.1021/nn301316j.
Turkowski, Volodymyr, Babu, Suresh, Le, Duy, Kumar, Amit, Haldar, Manas K., Wagh, Anil V., Hu, Zhongjian, Karakoti, Ajay S., Gesquiere, Andre J., Law, Benedict, Mallik, Sanku, Rahman, Talat S., Leuenberger, Michael N., and Seal, Sudipta. Tue . "Linker-Induced Anomalous Emission of Organic-Molecule Conjugated Metal-Oxide Nanoparticles". United States. doi:10.1021/nn301316j.
@article{osti_1177367,
title = {Linker-Induced Anomalous Emission of Organic-Molecule Conjugated Metal-Oxide Nanoparticles},
author = {Turkowski, Volodymyr and Babu, Suresh and Le, Duy and Kumar, Amit and Haldar, Manas K. and Wagh, Anil V. and Hu, Zhongjian and Karakoti, Ajay S. and Gesquiere, Andre J. and Law, Benedict and Mallik, Sanku and Rahman, Talat S. and Leuenberger, Michael N. and Seal, Sudipta},
abstractNote = {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 TiO2 and CeO2 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.},
doi = {10.1021/nn301316j},
journal = {ACS Nano, 6(6):4854-4863},
number = ,
volume = ,
place = {United States},
year = {2012},
month = {6}
}