@article{kim_atanasov_lemaire_lee_parsons_2015, title={Platinum-Free Cathode for Dye-Sensitized Solar Cells Using Poly(3,4-ethylenedioxythiophene) (PEDOT) Formed via Oxidative Molecular Layer Deposition}, volume={7}, ISSN={["1944-8244"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000350193000002&KeyUID=WOS:000350193000002}, DOI={10.1021/am5084418}, abstractNote={Thin ∼ 20 nm conformal poly(3,4-ehylenedioxythiophene) (PEDOT) films are incorporated in highly conductive mesoporous indium tin oxide (m-ITO) by oxidative molecular layer deposition (oMLD). These three-dimensional catalytic/conductive networks are successfully employed as Pt-free cathodes for dye-sensitized solar cells (DSSCs) with open circuit voltage equivalent to Pt cathode devices. Thin and conformal PEDOT films on m-ITO by oMLD create high surface area and efficient electron transport paths to promote productive reduction reaction on the PEDOT film. Because of these two synergetic effects, PEDOT-coated m-ITO by oMLD shows power conversion efficiency, 7.18%, comparable to 7.26% of Pt, and higher than that of planar PEDOT coatings, which is 4.85%. Thus, PEDOT-coated m-ITO is an exceptional opportunity to compete with Pt catalysts for low-cost energy conversion devices.}, number={7}, journal={ACS APPLIED MATERIALS & INTERFACES}, author={Kim, Do Han and Atanasov, Sarah E. and Lemaire, Paul and Lee, Kyoungmi and Parsons, Gregory N.}, year={2015}, month={Feb}, pages={3866–3870} }
 @article{lee_kim_parsons_2014, title={Free-Floating Synthetic Nanosheets by Atomic Layer Deposition}, volume={6}, ISSN={["1944-8252"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000339472100023&KeyUID=WOS:000339472100023}, DOI={10.1021/am502850p}, abstractNote={Two-dimensional (2D) nanosheets with distinctive properties are often fabricated by exfoliation, hydrothermal synthesis, or vapor-phase reaction. While these approaches are useful to generate nanosheets, we show that free-floating 2D metal oxide flakes with nanometer-scale thickness can also be formed by atomic layer deposition (ALD), where the ALD process allows the thickness and composition to be precisely tuned. In this work, we describe in detail the ALD nanosheet fabrication process and demonstrate how the choice of the sacrificial substrate affects the subsequent ALD processing and the resulting nanosheet thickness and surface structure. In addition, we introduce the fabrication of organic/inorganic bilayer nanosheets with unique potential applications.}, number={14}, journal={ACS APPLIED MATERIALS & INTERFACES}, author={Lee, Kyoungmi and Kim, Do Han and Parsons, Gregory N.}, year={2014}, month={Jul}, pages={10981–10985} }
 @article{lee_losego_kim_parsons_2014, title={High performance photocatalytic metal oxide synthetic bi-component nanosheets formed by atomic layer deposition}, volume={1}, ISSN={["2051-6355"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000348204200005&KeyUID=WOS:000348204200005}, DOI={10.1039/c4mh00012a}, abstractNote={Synthetic nanosheets that are ultrathin variants of bulk materials have been acquired using atomic layer deposition (ALD) on dissolvable substrates with a control over layer dimension including single and bilayered “Janus nanosheet” structures. TiO2, ZnO, Al2O3 and TiO2/ZnO nanosheets function as dispersible photocatalysts in aqueous media showing 3× synergistic rate enhancement for bilayered nanosheets.}, number={4}, journal={MATERIALS HORIZONS}, author={Lee, Kyoungmi and Losego, Mark D. and Kim, Do Han and Parsons, Gregory N.}, year={2014}, month={Jul}, pages={419–423} }
 @article{kim_losego_hanson_alibabaei_lee_meyer_parsons_2014, title={Stabilizing chromophore binding on TiO2 for long-term stability of dye-sensitized solar cells using multicomponent atomic layer deposition}, volume={16}, ISSN={["1463-9084"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000334602900050&KeyUID=WOS:000334602900050}, DOI={10.1039/c4cp01130a}, abstractNote={Dye sensitized solar cells (DSSCs) are coated with subnanometer oxide coatings to prevent device degradation in ambient humidity and high temperatures.}, number={18}, journal={PHYSICAL CHEMISTRY CHEMICAL PHYSICS}, author={Kim, Do Han and Losego, Mark D. and Hanson, Kenneth and Alibabaei, Leila and Lee, Kyoungmi and Meyer, Thomas J. and Parsons, Gregory N.}, year={2014}, pages={8615–8622} }
 @article{kim_woodroof_lee_parsons_2013, title={Atomic Layer Deposition of High Performance Ultrathin TiO2 Blocking Layers for Dye-Sensitized Solar Cells}, volume={6}, ISSN={["1864-564X"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000319828000011&KeyUID=WOS:000319828000011}, DOI={10.1002/cssc.201300067}, abstractNote={Abstract}, number={6}, journal={CHEMSUSCHEM}, author={Kim, Do Han and Woodroof, Mariah and Lee, Kyoungmi and Parsons, Gregory N.}, year={2013}, month={Jun}, pages={1014–1020} }
 @misc{parsons_atanasov_dandley_devine_gong_jur_lee_oldham_peng_spagnola_et al._2013, title={Mechanisms and reactions during atomic layer deposition on polymers}, volume={257}, ISSN={["1873-3840"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000327915000012&KeyUID=WOS:000327915000012}, DOI={10.1016/j.ccr.2013.07.001}, abstractNote={There is significant growing interest in atomic layer deposition onto polymers for barrier coatings, nanoscale templates, surface modification layers and other applications. The ability to control the reaction between ALD precursors and polymers opens new opportunities in ALD materials processing. It is well recognized that ALD on many polymers involves subsurface precursor diffusion and reaction which are not encountered during ALD on solid surfaces. This article reviews recent insights into chemical reactions that proceed during ALD on polymers, with particular focus on the common Al2O3 reaction sequence using trimethyl aluminum (TMA) and water. We highlight the role of different polymer reactive groups in film growth, and how the balance between precursor diffusion and reaction can change as deposition proceeds. As a strong Lewis acid, TMA forms adducts with Lewis base sites within the polymer, and the reactions that proceed are determined by the neighboring bond structure. Moreover, the Lewis base sites can be saturated by TMA, producing a self-limiting half-reaction within a three-dimensional polymer, analogous to a self-limiting half-reaction commonly observed during ALD on a solid planar surface.}, number={23-24}, journal={COORDINATION CHEMISTRY REVIEWS}, author={Parsons, Gregory N. and Atanasov, Sarah E. and Dandley, Erinn C. and Devine, Christina K. and Gong, Bo and Jur, Jesse S. and Lee, Kyoungmi and Oldham, Christopher J. and Peng, Qing and Spagnola, Joseph C. and et al.}, year={2013}, month={Dec}, pages={3323–3331} }
 @article{lee_jur_kim_parsons_2012, title={Mechanisms for hydrophilic/hydrophobic wetting transitions on cellulose cotton fibers coated using Al2O3 atomic layer deposition}, volume={30}, ISSN={["0734-2101"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000298992800063&KeyUID=WOS:000298992800063}, DOI={10.1116/1.3671942}, abstractNote={This report explores reactions that proceed during the first few cycles of inorganic film atomic layer deposition (ALD) on natural cellulose cotton fibers, and how surface reactions can explain the previously observed transitions in surface wetting upon ALD on cotton fibers. Atomic layer deposition of aluminum oxide and zinc oxide onto natural cotton cellulose produces a transition from hydrophilic to hydrophobic, then from hydrophobic back to hydrophilic, and we describe here the main factors that bring about. Interestingly, we show that air exposure and related adventitious carbon adsorption also affects the subsequent reactions and wetting properties obtained after subsequent ALD cycles. X-ray photoelectron spectroscopy and in situ Fourier transform infrared spectroscopy data indicate Al-(O-C-)3 bonding units form when trimethylaluminum interacts with surface –OH units during the first precursor doses, producing a hydrophobic finish on the cotton that remains for only a few ALD cycles. Also, field-emission scanning electron microscopy results show that some surface roughening may occur in the first few ALD cycles, and the roughening of the hydrophobic-finished surface can also promote an increase in measured hydrophobicity.}, number={1}, journal={JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A}, author={Lee, Kyoungmi and Jur, Jesse S. and Kim, Do Han and Parsons, Gregory N.}, year={2012}, month={Jan} }
 @article{kim_koo_jur_woodroof_kalanyan_lee_devine_parsons_2012, title={Stable anatase TiO2 coating on quartz fibers by atomic layer deposition for photoactive light-scattering in dye-sensitized solar cells}, volume={4}, ISSN={["2040-3372"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000306324000056&KeyUID=WOS:000306324000056}, DOI={10.1039/c2nr30939d}, abstractNote={Quartz fibers provide a unique high surface-area substrate suitable for conformal coating using atomic layer deposition (ALD), and are compatible with high temperature annealing. This paper shows that the quartz fiber composition stabilizes ALD TiO(2) in the anatase phase through TiO(2)-SiO(2) interface formation, even after annealing at 1050 °C. When integrated into a dye-sensitized solar cell, the TiO(2)-coated quartz fiber mat improves light scattering performance. Results also confirm that annealing at high temperature is necessary for better photoactivity of ALD TiO(2), which highlights the significance of quartz fibers as a substrate. The ALD TiO(2) coating on quartz fibers also boosts dye adsorption and photocurrent response, pushing the overall efficiency of the dye-cells from 6.5 to 7.4%. The mechanisms for improved cell performance are confirmed using wavelength-dependent incident photon to current efficiency and diffuse light scattering results. The combination of ALD and thermal processing on quartz fibers may enable other device structures for energy conversion and catalytic reaction applications.}, number={15}, journal={NANOSCALE}, author={Kim, Do Han and Koo, Hyung-Jun and Jur, Jesse S. and Woodroof, Mariah and Kalanyan, Berc and Lee, Kyoungmi and Devine, Christina K. and Parsons, Gregory N.}, year={2012}, pages={4731–4738} }
 @article{vasquez_vincent-johnson_hughes_augustine_lee_parsons_scarel_2012, title={Wetting properties induced in nano-composite POSS-MA polymer films by atomic layer deposited oxides}, volume={30}, ISSN={["0734-2101"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000298992800005&KeyUID=WOS:000298992800005}, DOI={10.1116/1.3639134}, abstractNote={Due to their unique properties, nano-composite polyhedral oligomeric silsequioxane (POSS) copolymer films are attractive for various applications. Here we show that their natural hydrophobic character can become hydrophilic when the films are modified by a thin oxide layer, up to 8 nm thick, prepared using atomic layer deposition. A proper choice of the deposition temperature and thickness of the oxide layer are required to achieve this goal. Unlike other polymeric systems, a marked transition to a hydrophilic state is observed with oxide layers deposited at increasing temperatures up to the glass transition temperature (∼110 °C) of the POSS copolymer film. The hydrophilic state is monitored through the water contact angle of the POSS film. Infrared absorbance spectra indicate that, in hydrophilic samples, the integral of peaks corresponding to surface Al–O (hydrophilic) is significantly larger than that of peaks linked to hydrophobic species.}, number={1}, journal={JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A}, author={Vasquez, Kyle A. and Vincent-Johnson, Anita J. and Hughes, W. Christopher and Augustine, Brian H. and Lee, Kyoungmi and Parsons, Gregory N. and Scarel, Giovanna}, year={2012}, month={Jan} }
 @article{gong_peng_jur_devine_lee_parsons_2011, title={Sequential Vapor Infiltration of Metal Oxides into Sacrificial Polyester Fibers: Shape Replication and Controlled Porosity of Microporous/Mesoporous Oxide Monoliths}, volume={23}, ISSN={0897-4756 1520-5002}, url={http://dx.doi.org/10.1021/cm200694w}, DOI={10.1021/cm200694w}, abstractNote={The preparation of microporous and mesoporous metal oxide materials continues to attract considerable attention, because of their possible use in chemical separations, catalyst support, chemical sensors, optical and electronic devices, energy storage, and solar cells. While many methods are known for the synthesis of porous materials, researchers continue to seek new methods to control pore size distribution and macroscale morphology. In this work, we show that sequential vapor infiltration (SVI) can yield shape-controlled micro/mesoporous materials with tunable pore size, using polyesters as a sacrificial template. The reaction proceeds by exposing polymer fiber templates to a controlled sequence of metal organic and co-reactant vapor exposure cycles in an atomic layer deposition (ALD) reactor. The precursors infuse sequentially and thereby distribute and react uniformly within the polymer, to yield an organic–inorganic hybrid material that retains the physical dimensions of the original polymer template...}, number={15}, journal={Chemistry of Materials}, publisher={American Chemical Society (ACS)}, author={Gong, Bo and Peng, Qing and Jur, Jesse S. and Devine, Christina K. and Lee, Kyoungmi and Parsons, Gregory N.}, year={2011}, month={Aug}, pages={3476–3485} }
 @article{kim_kim_kim_lee_parsons_park_2011, title={SiNx charge-trap nonvolatile memory based on ZnO thin-film transistors}, volume={99}, ISSN={["0003-6951"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000295034400043&KeyUID=WOS:000295034400043}, DOI={10.1063/1.3640221}, abstractNote={We have demonstrated the fabrication and application of a nonvolatile thin-film transistor memory with SiNx charge traps using a ZnO thin film as the active channel layer. The thin film of ZnO was deposited using an atomic-layer deposition process and was subsequently post-annealed in an O2-filled atmosphere. X-ray diffraction and x-ray photoemission results indicated that the O2 annealing process was effective for the crystallinity and stoichiometry of the ZnO films. A saturation field-effect mobility of 6 cm2/Vs, on/off ratio of ≈105, subthreshold slope of 0.7 V/decade, and threshold voltage of −5 V were obtained in transistor operations. Threshold-voltage shift measurements performed for various stress voltages and time durations revealed that these devices had a large memory window of 5.4 V and a long retention time (>10 years) in nonvolatile memory operations.}, number={11}, journal={APPLIED PHYSICS LETTERS}, author={Kim, Eunkyeom and Kim, Youngill and Kim, Do Han and Lee, Kyoungmi and Parsons, Gregory N. and Park, Kyoungwan}, year={2011}, month={Sep} }
 @article{hyde_scarel_spagnola_peng_lee_gong_roberts_roth_hanson_devine_et al._2010, title={Atomic Layer Deposition and Abrupt Wetting Transitions on Nonwoven Polypropylene and Woven Cotton Fabrics}, volume={26}, ISSN={["0743-7463"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000274342200056&KeyUID=WOS:000274342200056}, DOI={10.1021/la902830d}, abstractNote={Atomic layer deposition (ALD) of aluminum oxide on nonwoven polypropylene and woven cotton fabric materials can be used to transform and control fiber surface wetting properties. Infrared analysis shows that ALD can produce a uniform coating throughout the nonwoven polypropylene fiber matrix, and the amount of coating can be controlled by the number of ALD cycles. Upon coating by ALD aluminum oxide, nonwetting hydrophobic polypropylene fibers transition to either a metastable hydrophobic or a fully wetting hydrophilic state, consistent with well-known Cassie-Baxter and Wenzel models of surface wetting of roughened surfaces. The observed nonwetting/wetting transition depends on ALD process variables such as the number of ALD coating cycles and deposition temperature. Cotton fabrics coated with ALD aluminum oxide at moderate temperatures were also observed to transition from a natural wetting state to a metastable hydrophobic state and back to wetting depending on the number of ALD cycles. The transitions on cotton appear to be less sensitive to deposition temperature. The results provide insight into the effect of ALD film growth mechanisms on hydrophobic and hydrophilic polymers and fibrous structures. The ability to adjust and control surface energy, surface reactivity, and wettability of polymer and natural fiber systems using atomic layer deposition may enable a wide range of new applications for functional fiber-based systems.}, number={4}, journal={LANGMUIR}, author={Hyde, G. Kevin and Scarel, Giovanna and Spagnola, Joseph C. and Peng, Qing and Lee, Kyoungmi and Gong, Bo and Roberts, Kim G. and Roth, Kelly M. and Hanson, Christopher A. and Devine, Christina K. and et al.}, year={2010}, month={Feb}, pages={2550–2558} }
 @article{jur_spagnola_lee_gong_peng_parsons_2010, title={Temperature-Dependent Subsurface Growth during Atomic Layer Deposition on Polypropylene and Cellulose Fibers}, volume={26}, ISSN={["0743-7463"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000277928100078&KeyUID=WOS:000277928100078}, DOI={10.1021/la904604z}, abstractNote={Nucleation and subsequent growth of aluminum oxide by atomic layer deposition (ALD) on polypropylene fiber substrates is strongly dependent on processing temperature and polymer backbone structure. Deposition on cellulose cotton, which contains ample hydroxyl sites for ALD nucleation and growth on the polymer backbone, readily produces a uniform and conformal coating. However, similar ALD processing on polypropylene, which contains no readily available active sites for growth initiation, results in a graded and intermixed polymer/inorganic interface layer. The structure of the polymer/inorganic layer depends strongly on the process temperature, where lower temperature (60 degrees C) produced a more abrupt transition. Cross-sectional transmission electron microscopy images of polypropylene fibers coated at higher temperature (90 degrees C) show that non-coalesced particles form in the near-surface region of the polymer, and the particles grow in size and coalesce into a film as the number of ALD cycles increases. Quartz crystal microbalance analysis on polypropylene films confirms enhanced mass uptake at higher processing temperatures, and X-ray photoelectron spectroscopy data also confirm heterogeneous mixing between the aluminum oxide and the polypropylene during deposition at higher temperatures. The strong temperature dependence of film nucleation and subsurface growth is ascribed to a relatively large increase in bulk species diffusivity that occurs upon the temperature-driven free volume expansion of the polypropylene. These results provide helpful insight into mechanisms for controlled organic/inorganic thin film and fiber materials integration.}, number={11}, journal={LANGMUIR}, author={Jur, Jesse S. and Spagnola, Joseph C. and Lee, Kyoungmi and Gong, Bo and Peng, Qing and Parsons, Gregory N.}, year={2010}, month={Jun}, pages={8239–8244} }