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Title: Effect of Moisture on Dopant Segregation in Solid Hosts

Abstract

Transition metal-doped semiconductor materials are extensively employed for light harvesting and photocatalytic applications owing to their increased light absorption and charge mobility. Here, spatial tailoring of the Ni dopant in TiO 2 nanostructures is performed by varying the secondary processing parameters to engineer the resulting optoelectronic properties for select applications. Specifically, the aging of the dried Ti sol and the resulting Ni segregation are observed to be moisture-driven phenomena based on the infrared and time-resolved UV–vis spectroscopy measurements. While X-ray diffraction and scanning transmission electron microscopy coupled with electron energy-loss spectroscopy characterizations show a clear difference in the crystal structures between pristine TiO 2 powders and phase-segregated NiO–TiO 2, the thermogravimetric measurements reveal substitution of the ethoxy group by ambient moisture, resulting in the ejection of hydroxylated Ni clusters. Moreover, the doped system could be locked into a metastable state by rapidly annealing the amorphous powders. Lastly, the photocatalytic activity of these different TiO 2:Ni 2+ (15 mol %) nanoparticles under AM 1.5G solar light highlights the relationship between the photocatalytic activity and the dopant position. This ability to spatially control dopants within highly doped materials allows for direct control of specific optoelectronic properties, paramount for photoelectrochemical devices.

Authors:
 [1];  [1];  [2]; ORCiD logo [3]; ORCiD logo [1]; ORCiD logo [1]
  1. Louisiana State Univ., Baton Rouge, LA (United States)
  2. Louisiana State Univ., Baton Rouge, LA (United States); Southern Univ. and A&M College, Baton Rouge, LA (United States)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1531233
Grant/Contract Number:  
AC05-00OR22725
Resource Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. C
Additional Journal Information:
Journal Volume: 123; Journal Issue: 19; Journal ID: ISSN 1932-7447
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS

Citation Formats

Darapaneni, Pragathi, Moura, Natalia S., Harry, Darrell, Cullen, David A., Dooley, Kerry M., and Dorman, James A. Effect of Moisture on Dopant Segregation in Solid Hosts. United States: N. p., 2019. Web. doi:10.1021/acs.jpcc.9b01067.
Darapaneni, Pragathi, Moura, Natalia S., Harry, Darrell, Cullen, David A., Dooley, Kerry M., & Dorman, James A. Effect of Moisture on Dopant Segregation in Solid Hosts. United States. doi:10.1021/acs.jpcc.9b01067.
Darapaneni, Pragathi, Moura, Natalia S., Harry, Darrell, Cullen, David A., Dooley, Kerry M., and Dorman, James A. Fri . "Effect of Moisture on Dopant Segregation in Solid Hosts". United States. doi:10.1021/acs.jpcc.9b01067.
@article{osti_1531233,
title = {Effect of Moisture on Dopant Segregation in Solid Hosts},
author = {Darapaneni, Pragathi and Moura, Natalia S. and Harry, Darrell and Cullen, David A. and Dooley, Kerry M. and Dorman, James A.},
abstractNote = {Transition metal-doped semiconductor materials are extensively employed for light harvesting and photocatalytic applications owing to their increased light absorption and charge mobility. Here, spatial tailoring of the Ni dopant in TiO2 nanostructures is performed by varying the secondary processing parameters to engineer the resulting optoelectronic properties for select applications. Specifically, the aging of the dried Ti sol and the resulting Ni segregation are observed to be moisture-driven phenomena based on the infrared and time-resolved UV–vis spectroscopy measurements. While X-ray diffraction and scanning transmission electron microscopy coupled with electron energy-loss spectroscopy characterizations show a clear difference in the crystal structures between pristine TiO2 powders and phase-segregated NiO–TiO2, the thermogravimetric measurements reveal substitution of the ethoxy group by ambient moisture, resulting in the ejection of hydroxylated Ni clusters. Moreover, the doped system could be locked into a metastable state by rapidly annealing the amorphous powders. Lastly, the photocatalytic activity of these different TiO2:Ni2+ (15 mol %) nanoparticles under AM 1.5G solar light highlights the relationship between the photocatalytic activity and the dopant position. This ability to spatially control dopants within highly doped materials allows for direct control of specific optoelectronic properties, paramount for photoelectrochemical devices.},
doi = {10.1021/acs.jpcc.9b01067},
journal = {Journal of Physical Chemistry. C},
number = 19,
volume = 123,
place = {United States},
year = {2019},
month = {5}
}

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This content will become publicly available on May 3, 2020
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