Premium
Microfluidics: Nanostructuring of Titania Thin Films by a Combination of Microfluidics and Block‐Copolymer‐Based Sol–Gel Templating (Small 7/2011)
Author(s) -
Rawolle Monika,
Ruderer Matthias A.,
Prams Stefan M.,
Zhong Qi,
Magerl David,
Perlich Jan,
Roth Stephan V.,
Lellig Philipp,
Gutmann Jochen S.,
MüllerBuschbaum Peter
Publication year - 2011
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201190021
Subject(s) - materials science , mesoporous material , microfluidics , grazing incidence small angle scattering , thin film , chemical engineering , scanning electron microscope , nanotechnology , siloxane , substrate (aquarium) , copolymer , silicon , scattering , optoelectronics , composite material , optics , polymer , small angle neutron scattering , organic chemistry , chemistry , physics , neutron scattering , engineering , oceanography , catalysis , geology
Sol–gel templating of titania thin films with the amphiphilic diblock copolymer poly(dimethyl siloxane)‐ block ‐methyl methacrylate poly(ethylene oxide) is combined with microfluidic technology to control the structure formation. Due to the laminar flow conditions in the microfluidic cell, a better control of the local composition of the reactive fluid is achieved. The resulting titania films exhibit mesopores and macropores, as determined with scanning electron microscopy, X‐ray reflectivity, and grazing incidence small angle X‐ray scattering. The titania morphology has three features that are beneficial for application in photovoltaics: 1) a large surface‐to‐volume ratio important for charge generation with disordered hexagonally arranged mesopores of 25 nm size and a film porosity of up to 0.79, 2) enhanced light scattering that enables the absorption of more light, and 3) a dense titania layer with a thickness of about 6 nm at the substrate (bottom electrode) to prevent short circuits. An optical characterization complements the structural investigation.