Eylem Seç
Pulsed Photoinitiated Fabrication of Transition Metal Oxides-Reduced Graphitic Oxides Nanocomposite Thin Films
Başlık:
Pulsed Photoinitiated Fabrication of Transition Metal Oxides-Reduced Graphitic Oxides Nanocomposite Thin Films
Yazar:
Luo, Sijun, author.
ISBN:
9780438073432
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (105 pages)
Genel Not:
Source: Dissertation Abstracts International, Volume: 79-10(E), Section: B.
Advisors: Douglas B. Chrisey Committee members: Zhiqiang Mao; Noshir S. Pesika; Jiang Wei.
Özet:
Nanostructured transition metal oxide-carbon composite thin films with the large specific surface area show great promise for use in thin film batteries and sensors. The cost-efficient manufacturing is essential for their practical integration in portable electronics and microelectromechanical systems that will have huge market and increasing demands in the next decade. However, eco-friendly low-cost and high-throughput production of the composite thin films has been a significant challenge due to stringent low-cost industrialization requirements which present thin film processing methods cannot meet. My study focuses on a novel approach to instantaneous photoinitiated synthesis and rapid in-situ photothermal treatment of nanostructured transition metal oxides-reduced graphitic oxides (rGO) composite thin films through pulsed light irradiation of organometallic precursor films.
We demonstrate an approach to instantaneous photoinitiated synthesis of mixed anatase-rutile nanocrystalline TiO2-rGO nanocomposite thin films through pulsed light irradiation of photosensitive Ti-acetylacetonate liquid precursor films made by spin coating. Pulsed photoinitiated pyrolysis accompanied by instantaneous self-assembly and crystallization occurred in-situ to form reduced graphitic oxides-coated TiO2 nanograins in the nanocomposite thin films with a three-dimensional (3D) nanostructure consisting of a porous dendritic top layer and a dense bottom layer. Subsequent pulsed light irradiation, working as in-situ pulsed photothermal treatment, improved the crystalline quality of TiO2 film despite its low attenuation of light. The non-radiative recombination of photogenerated electrons and holes in TiO2 nanograins, coupled with inefficient heat dissipation due to low thermal conductivity, produces enough heat to provide a thermodynamic driving force for improving crystal quality. The pristine reduced graphitic oxides in the as-synthesized thin film were further reduced by pulsed photothermal treatment and can be completely removed by oxygen plasma cleaning.
We also demonstrate instantaneous photoinitiated synthesis of nanocrystalline cobalt oxide-rGO nanocomposite thin films with a 3D nanostructure, in ambient condition, through pulsed light irradiation of spray-coated Co-acetylacetonate solid precursor films. The instantaneous self-assembly and crystallization of the nanocomposite thin films are achieved through the pulsed photoinitiated pyrolysis of Co-acetylacetonate molecules in the first 2 pulses. The subsequent pulses of irradiation improved the crystalline quality of CoO nanograins and evaporated the carbon components through the pulsed photothermal effect due to the very high attenuation of light of cobalt oxides. The nanocomposite thin films, fabricated on commercial Pt-coated Si substrates, with higher content of rGO or under less pulse of irradiation exhibit better faraday capacitive performance and longer life time in 1M KOH aqueous electrolyte in a three-electrode cell. The as-synthesized CoO-rGO nanocomposite thin film after 2 pulses of irradiation shows a specific areal capacitance as high as 6.5 mF/cm 2 at 0.2 mA/cm2 and an excellent rate capability of 80 % retention from 5 uA/cm2 to 0.5 mA/cm2 after 20000 times of stable charge-discharge cycling.
This study demonstrates a photoinitiated nanofabrication technology to achieve instantaneous pulsed photoinitiated pyrolysis synthesis combined with rapid in-situ photothermal treatment of nanocrystalline transition metal oxides-rGO nanocomposite thin films through simple pulsed light irradiation, opening a way to low-cost and high-throughput production of the complex nanostructured composite thin films for energy, environmental and health applications.
Notlar:
School code: 0494
Tüzel Kişi Ek Girişi:
Mevcut:*
Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
---|---|---|---|
XX(677980.1) | 677980-1001 | Proquest E-Tez Koleksiyonu | Arıyor... |
On Order
Liste seç
Bunu varsayılan liste yap.
Öğeler başarıyla eklendi
Öğeler eklenirken hata oldu. Lütfen tekrar deneyiniz.
:
Select An Item
Data usage warning: You will receive one text message for each title you selected.
Standard text messaging rates apply.