التفاصيل البيبلوغرافية
| العنوان: |
Ultrasonic spray deposition of mesoporous, nanocrystalline tungsten oxide films for smart windows |
| المؤلفون: |
Li, Chi-Ping |
| المساهمون: |
Wolden, Colin Andrew, Knauss, Daniel M., Herring, Andrew M., O'Hayre, Ryan P., Tenent, Robert C. |
| بيانات النشر: |
Colorado School of Mines. Arthur Lakes Library |
| سنة النشر: |
2007 |
| المجموعة: |
Mountain Scholar (Digital Collections of Colorado and Wyoming) |
| مصطلحات موضوعية: |
electrochromic window, ultrasonic spray deposition, tungsten oxide, sol-gel, mesoporous, Electrochromic devices, Thin films, Ultrasonics in metallurgy, Tungsten oxides, Mesoporous materials, Nanocomposites (Materials), Windows -- Technological innovations |
| الوصف: |
2014 Spring. ; Includes illustrations (some color). ; Includes bibliographical references. ; Electrochromic smart windows modulate their optical transparency in response to a small voltage, and are employed to tailor lighting conditions within a structure with the potential of significant energy savings. The two bottlenecks preventing wide spread implementation of electrochromic windows are cost and performance. In this thesis ultrasonic spray deposition (USD) is developed as a scalable, low cost manufacturing alternative to vacuum processes for the fabrication of mesoporous, nanocrystalline tungsten oxide thin films, the leading electrochromic. In the first approach, tungsten oxide nanoparticles (NP) were synthesized by hot-wire chemical vapor deposition (HWCVD), suspended in ethanol, and deposited on FTO substrates using USD. Nanoparticle morphology and size was controlled by tuning the HWCVD parameters such as filament temperature, substrate temperature, and oxygen partial pressure. Electrochromic performance like coloration efficiency and charge capacity improved by reducing the size of nanoparticles and consequently increasing the specific surface area. However, it was difficult to reduce NP size below ~15 nm, and scaling HWCVD to large volumes is challenging. In the second approach conventional template-assisted sol-gel chemistry was adapted to ultrasonic spray deposition. It was found that the performance is strongly related to annealing procedure, resulting in films with good optical modulation (75%) and fast switching (<10 s). The kinetics of the sol-gel process was quantified using UV-Vis spectroscopy, and performance was correlated to film composition (FTIR, Raman), morphology (SEM, BET) and crystallinity (TEM, XRD, SAD). Systematic manipulation of sol chemistry produced micron thick films with high specific surface area (>100 m2/g), mean pore sizes of ~5 nm, and narrow pore size distributions. These films display world record electrochromic performance, modulating >98% of incident solar ... |
| نوع الوثيقة: |
text |
| وصف الملف: |
born digital; doctoral dissertations; application/pdf |
| اللغة: |
English |
| العلاقة: |
2014 - Mines Theses & Dissertations; T 7446; http://hdl.handle.net/11124/370Test |
| الإتاحة: |
http://hdl.handle.net/11124/370Test |
| حقوق: |
Copyright of the original work is retained by the author. ; 6-month embargo |
| رقم الانضمام: |
edsbas.80972B49 |
| قاعدة البيانات: |
BASE |
