KATI HAL ELEKTROKROMİK AYGIT TASARIMI, HAZIRLANMASI VE KARAKTERİZASYONU

Abstract

The rapid increase in the world population and the increase in energy consumption have made the efficient use of existing energy resources controversial both in terms of scientific and sustainable life cycle. In recent years, studies on the development of electrochromic (EC) materials and multilayer EC coatings/devices that change color with externally applied voltage have accelerated in order to use existing energy resources efficiently and reduce possible energy losses.

Within the scope of this thesis, the films to be used in the preparation of EC devices were deposited on glass and PET substrates using the RF magnetron sputtering technique and their structural, optical and electrochromic properties were investigated. WO3 thin films, known to have cathodic coloration, deposited at 10 mTorr Ar pressure, were grown on glass substrates with a thickness of 400 mm. The average optical modulations of these films in the visible and near infrared wavelengths (2.2V) are 67.2% and 79.0%, respectively. The average optical modulations (2.2V) at visible and near infrared wavelengths of 400 nm thick WO3 thin films deposited on flexible PET substrate are 66.03% and 81.10%, respectively. Li4Ti5O12 and Ta2O5 thin films, which were used as ion conductive layers in EC devices with full cell configuration, were prepared on glass and PET substrates and their structural, optical and electrochromic properties were investigated. The effects of the thickness of the ion conductive layers used in EC devices prepared in half-cell configuration on the optical and electrochromic properties of the devices were investigated in detail. The highest average optical modulation (2.2V) in the visible and near-infrared wavelengths of the EC half cell with Li4Ti5O12/WO3/ITO/glass configuration deposited on glass substrates, respectively, has a Li4Ti5O12 ion conductive layer with a thickness of d = 110 nm deposited at PAr = 10 mTorr pressure. For the cell, 74.8% and 75.1% (PAr = 30 mTorr, d (Li4Ti5O12) = 69 nm) were obtained. The highest coloration efficiency in half cells on glass substrate reached 53.36 cm2/C (PAr = 10 mTorr, d(Li4Ti5O12) = 110 nm). The highest average optical modulation (2.2V) in the visible and near infrared regions of the half cell with d = 40 nm thick Li4Ti5O12 ion conductive layer deposited at PAr = 30 mTorr pressure in the Li4Ti5O12/WO3/ITO/PET configuration was 73.18% and 82%, respectively. is .23. The highest coloration efficiency of half cells with the same configuration deposited on flexible substrate is 290.38 cm2/C (PAr = 10 mTorr, d(Li4Ti5O12) = 110 nm).

The highest average optical modulation (2.2V) of the half-cell in the Ta2O5/WO3/ITO/glass configuration in the visible and near infrared region is 74.04% and 80.36%, respectively (PAr = 10 mTorr, d(Ta2O5) = 230 nm ). The highest coloration efficiency is 59 cm2/C (PAr = 10 mTorr, d(Ta2O5) = 230 nm). The highest average optical modulations (2.2V) in the visible and near-infrared regions of half cells with Ta2O5/WO3/ITO/PET configuration are 66.69% and 81.32%, respectively (PAr = 10 mTorr, d(Ta2O5) = 170nm). The coloration efficiency of half cells deposited on flexible substrates reached the highest value of 96.31 cm2/C (PAr = 10 mTorr, d(Ta2O5) = 280 nm).

Half cells formed by primary (WO3), secondary/counter (NiO) electrochromic films and ion conductive (Li4Ti5O12, Ta2O5) films are appropriately combined with LiClO4/PC electrolyte lamination method and EC devices in full cell configuration (Substrate/NiO/LiClO4/ PC Li4Ti5O12 or Ta2O5/WO3/ITO/Substrate) was prepared. In EC devices with a Li4Ti5O12 ion conductive layer on the glass substrate, the highest average optical modulation (3 V) in the visible region is 66.43%, while it is 76.71% in the near infrared region. In EC devices deposited on PET substrate, the highest average optical modulation (±3V) is 55.00% in the visible region (PAr = 20 mTorr, d(Li4Ti5O12) = 50 nm) and 68.31% in the near infrared region (PAr = 30 mTorr, d(Li4Ti5O12) = 59 nm).

The highest modulation (±2V) in the visible region of EC devices on glass substrate with a 170 nm thick Ta2O5 ion conductive layer deposited at PAr = 10mTorr is 65.80%. The highest modulation (±2V) in the near infrared region of EC devices with a 280 nm thick Ta2O5 ion conductive layer deposited at PAr = 10mTorr is 74.09%. The highest average optical modulation (±2V) for the visible and infrared regions of EC devices deposited on flexible PET substrates with a 230 nm thick Ta2O5 ion conductive layer deposited at PAr = 10 mTorr is 60.46% and 71.51%, respectively.

All solid-state EC devices with modulated EC properties can be prepared using layers with improved electrochromic performance by liquid and solid lithiation processes using appropriate procedures and amounts.