Epitaxial Formation Mechanism of Multilayer TiO 2 Films with Ordered Accessible Vertical Nanopores by Evaporation-Driven Assembly
Abstract
Surfactant-templated mesoporous titania (TiO2) films have excellent physical and electronic properties, but some potential applications require films thicker than the 100-200 nm typically prepared by sol-gel coating. Here, the mechanism of forming micron-thick TiO2 films with vertically oriented nanopore channels by a layer-by-layer deposition technique (up to eight 125 nm-thick layers) is investigated. In situ grazing incidence small angle x-ray scattering (GISAXS) performed on successive layers of Pluronic F127-templated films reveals if and how epitaxially oriented layers form during aging at 4 °C. At 78% relative humidity (RH), films cast onto substrates modified with crosslinked F127 maintain (011)-oriented Im3m cubic mesophase order, whereas micelles on unmodified glass lose their preferred orientation, leading to the observation of an arc in GISAXS attributed to an anisotropic micelle structure. A similar arc from randomly oriented domains is found at low RH (38%) regardless of substrate modification. Avrami model analysis shows that each oriented epitaxial layer followed formation kinetics with the same order (n=1.8±0.3) and half-life (10-20 min). Cross-sectional electron microscopy and impedance spectroscopy of the films after calcination at 400 °C show the formation of continuous, accessible vertical pore channels by micelle fusion for mesophases properly oriented by initial substrate modification.
- Authors:
-
;
[1];
;
- X-ray Science Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
- Publication Date:
- Research Org.:
- Argonne National Lab. (ANL), Argonne, IL (United States); Univ. of Kentucky, Lexington, KY (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities Division; National Science Foundation (NSF)
- Contributing Org.:
- Advanced Photon Source, Argonne National Laboratory
- OSTI Identifier:
- 1580579
- Alternate Identifier(s):
- OSTI ID: 1603349
- Grant/Contract Number:
- AC02-06CH11357
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Journal of Physical Chemistry. C
- Additional Journal Information:
- Journal Volume: 124; Journal Issue: 3; Journal ID: ISSN 1932-7447
- Publisher:
- American Chemical Society
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; nanoporous TiO2; multilayer film; epitaxial growth; in situ; GISAXS; surface modification; surfactant templating; battery; photocatalysis
Citation Formats
Khan, M. Arif, Islam, Syed Z., Nagpure, Suraj, He, Yuxin, Wanninayake, Namal, Palmer, Rebecca L., Strzalka, Joseph, Kim, Doo Young, Knutson, Barbara L., and Rankin, Stephen E. Epitaxial Formation Mechanism of Multilayer TiO 2 Films with Ordered Accessible Vertical Nanopores by Evaporation-Driven Assembly. United States: N. p., 2019.
Web. doi:10.1021/acs.jpcc.9b09376.
Khan, M. Arif, Islam, Syed Z., Nagpure, Suraj, He, Yuxin, Wanninayake, Namal, Palmer, Rebecca L., Strzalka, Joseph, Kim, Doo Young, Knutson, Barbara L., & Rankin, Stephen E. Epitaxial Formation Mechanism of Multilayer TiO 2 Films with Ordered Accessible Vertical Nanopores by Evaporation-Driven Assembly. United States. https://doi.org/10.1021/acs.jpcc.9b09376
Khan, M. Arif, Islam, Syed Z., Nagpure, Suraj, He, Yuxin, Wanninayake, Namal, Palmer, Rebecca L., Strzalka, Joseph, Kim, Doo Young, Knutson, Barbara L., and Rankin, Stephen E. Thu .
"Epitaxial Formation Mechanism of Multilayer TiO 2 Films with Ordered Accessible Vertical Nanopores by Evaporation-Driven Assembly". United States. https://doi.org/10.1021/acs.jpcc.9b09376. https://www.osti.gov/servlets/purl/1580579.
@article{osti_1580579,
title = {Epitaxial Formation Mechanism of Multilayer TiO 2 Films with Ordered Accessible Vertical Nanopores by Evaporation-Driven Assembly},
author = {Khan, M. Arif and Islam, Syed Z. and Nagpure, Suraj and He, Yuxin and Wanninayake, Namal and Palmer, Rebecca L. and Strzalka, Joseph and Kim, Doo Young and Knutson, Barbara L. and Rankin, Stephen E.},
abstractNote = {Surfactant-templated mesoporous titania (TiO2) films have excellent physical and electronic properties, but some potential applications require films thicker than the 100-200 nm typically prepared by sol-gel coating. Here, the mechanism of forming micron-thick TiO2 films with vertically oriented nanopore channels by a layer-by-layer deposition technique (up to eight 125 nm-thick layers) is investigated. In situ grazing incidence small angle x-ray scattering (GISAXS) performed on successive layers of Pluronic F127-templated films reveals if and how epitaxially oriented layers form during aging at 4 °C. At 78% relative humidity (RH), films cast onto substrates modified with crosslinked F127 maintain (011)-oriented Im3m cubic mesophase order, whereas micelles on unmodified glass lose their preferred orientation, leading to the observation of an arc in GISAXS attributed to an anisotropic micelle structure. A similar arc from randomly oriented domains is found at low RH (38%) regardless of substrate modification. Avrami model analysis shows that each oriented epitaxial layer followed formation kinetics with the same order (n=1.8±0.3) and half-life (10-20 min). Cross-sectional electron microscopy and impedance spectroscopy of the films after calcination at 400 °C show the formation of continuous, accessible vertical pore channels by micelle fusion for mesophases properly oriented by initial substrate modification.},
doi = {10.1021/acs.jpcc.9b09376},
journal = {Journal of Physical Chemistry. C},
number = 3,
volume = 124,
place = {United States},
year = {Thu Dec 26 00:00:00 EST 2019},
month = {Thu Dec 26 00:00:00 EST 2019}
}
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