Desıgn Of Solıd Electrochromıc Devıce

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2012Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2012Bu çalışmanın amacı, her tabakası sol-jel yöntemi ile üretilmiş (geçirgen iletken tabaka olarak kullanılan ITO hariç) katı elektrokromik cihaz (KEC) tasarımıdır. Katı elektrokromik cihazı oluşturacak her katman ilk aşamada farklı iyonlar (Li+, Na+, Cs+) içeren sıvı elekrolitler içinde elektrokimyasal ve optik özellikleri bakımından detaylı olarak incelenmiştir. Tungsten oksit ve vanadyum oksit filmler yaklaşık 100-150 nm kalınlığında olacak şekilde sol-jel kaplama yöntemlerinden biri olan daldırma yöntemi ile kaplanmıştır. Yedi katmanlı sandviç yapıdaki katı elektroktromik cihaz yapımı ticari olarak alınan elektrolit (PAMPSA) kullanılarak tamamlandıktan sonra farklı tuzlar içeren (LiClO4, NaClO4, CsClO4) elektrolitlerin üretimi yapılmıştır. Bu şekilde KEC farklı iyonlar içeren elektrolitler kullanılarak yapılmış ve bu iyonların katı elektrokromik cihazın elektrokromik ve optik özeliklerini nasıl değiştirdiği sistematik şekilde incelenmiştir. Üretimi yapılan katı elektrokromik cihazların elekrokimyasal özellikleri elektrolit içinde bulunan farklı iyonların davranışlarına göre kıyaslanmıştır. Bu iyonların elektrokromik aktif tabakaya giriş çıkış kinetiği, yük miktarı, renklenme miktarı, tersinirliği ve cihazların dayanıklılığı ve kararlığı araştırılmıştır. Bu iyonlar kullanılarak hazırlanan katı elektrokromik cihazların her katmanının optimizasyonu yapıldıktan sonra katı elektrokromik cihazlar çalışır hale getirilmiştir. Üretimi yapılan katı elektrokromik cihazların elektrokromik özellikleri literatürdeki mevcut katı elektrokromik cihazlar ile kıyaslanabilecek durumdadır. Literatürde Cs+ iyonu kullanılarak üretilmiş katı elektrokromik cihaz ve elektrokimyasal analizlerinin detaylı olarak incelendiği çalışma bulunmamaktadır. Bu çalışmada Cs+ iyonu içeren katı elektrokromik cihaz çalıştırılmış ve tersinir şekilde renklenmesi sağlanmıştır. Farklı iyonlar kullanılarak hem sıvı hem de katı elektrokromik cihaz üretiminin sistemli şekilde incelenmesi literatüre önemli bir katkı getirmektedir.The purpose of this study is designing of solid electrochromic device whose layers are made up of by the sol-gel method (except ITO which is used as a transparent conductive layer). Every layer which builds up the solid electrochromic device is investigated in detail with respect to their electrochemical and optical properties in different liquid electrolytes including the different ions (Li+, Na+, Cs+). Tungsten oxide and vanadium oxide films were coated with dip-coating method which is one of the sol-gel methods and the thicknesses of these films were around 100-150 nm. After completing the fabrication of seven layers of sandwichlike structure solid electrochromic device with the electrolyte (PAMPSA) which was taken as commercially, the electrolytes including different salts (LiClO4, NaClO4, CsClO4) were produced. In this way, the solid electrochromic device was made by using the electrolytes including different ions and it was investigated systematically how these ions changed the optical and electrochromical properties of this solid electrochromic device. The electrochemical properties of solid electrochromic devices which have been performed in this study are comparable with the solid electrochromic devices included in literature. In literature, the detailed investigations of fabricated solid electrochromic device by using Cs+ ion and electrochemical analyses of them don’t exist. In this study, solid electrochromic device including Cs+ ion was brought to good working order and reversibly colour change of this device was maintained. Investigating the fabrication of both liquid and solid electrochromic devices systematically by using different ions will make a huge contribution to the literature.Yüksek LisansM.Sc

Investigating the effect of electrolyte types with various ionic liquids on the electrochromic performance of PEDOT:PSS based LbL multilayers

The objective of the study is to investigate the electrochromic performances of layer-by-layer (LbL) multilayered thin film electrode prepared from linear polyethylene imine (LPEI) and poly(3,4-ethylenediox-ythiophene):polystyrene sulfonate (PEDOT:PSS) on PET-ITO substrate in the presence of different types of electrolytes. For this purpose, the electrochromic behaviors of (LPEI/PEDOT:PSS) 10 is performed in LiClO4/propylene carbonate (PC) and two different ionic liquids (IL) namely N-methylimidazolium tetrafluoroborate (Melm-BF4) and 2-hydroxy ethyl ammonium formate (2-HEAF), as a function of IL content and scanning rate. The optical contrast value of (LPEI/PEDOT:PSS) 10 film is determined as 58.4% in the existence of 10 wt% of 2-HEAF as the electrolyte. The coloration efficiency of this film is determined as 606.7 cm(2)/C, which this value was greater approximately four times than 1 M LiClO4/PC. According to the obtained results, 2-HEAF has been evaluated as a suitable electrolyte alternative for (LPEI/PEDOT:PSS) 10 film due to its better optical contrast and coloration efficiency compared to other electrolytes

Smart glass electrochromic device fabrication of uniform tungsten oxide films from its powder synthesized by solution combustion method

Recently, there has been renewed interest in tungsten oxide based electrochromic (EC) materials. A variety of studies related to these materials have been reported, however, no serious studies so far have been reported on the electrochromic effect of tungsten oxide that is synthesized by solution combustion method. The major advantage of this process is the ease and simplicity with preparing nanosize oxides. Herein, the principal objective of this project was to produce uniform and adhesive tungsten oxide thin films from as-synthesized powder by solution combustion route for EC device. Although extensive research has been carried out on EC properties of tungsten oxide, limited study exists in e-beam evaporated tungsten oxide thin film studies for smart window application. Therefore, tungsten oxide thin films were deposited from our own produced powder by e-beam evaporation. To present the effect of new powder on the properties of the thin films, their physical and morphological properties were compared with thin film deposited by commercial tungsten oxide powder. Finally, electrochemical and optical characteristics of an all-solid-state EC device with a structure of glass/ITO/SCS-WO3/Nafion/ITO/glass with high optical transmittance modulation (63% at 550 nm) was fabricated. This study has been one of the first attempts to thoroughly examine in detail of tungsten oxide powder synthesized by solution combustion method for EC active layer. These findings contribute in several ways to our understanding of solution combustion synthesized powder to be used for production of EC active layer of thin film and provide a basis for developing and designing energy-efficient EC active materials and devices