氧化鎢薄膜應用於可撓式電致色變元件之彎曲效應下著色記憶保持能力研究

Abstract

本研究以電沉積法製備氧化鎢電致色變薄膜，將氧化鎢沉積在可撓性塑膠基板上來製備成可撓性顯示器。本研究主要分為三個部分進行，第一部分測試電沉積法鍍膜及著去色電位之最佳參數，並探討張應力、壓應力、彎曲次數、彎曲半徑、溫度對於電致色變薄膜記憶保持能力的影響，進而探討其薄膜的穿透率、穿透率差、著色效率，再觀察其薄膜表面形貌、粗糙度，最後使用電壓-電流來對電致色變薄膜進行電性量測。第二部分為利用Light tools光學模擬工具來進行模擬薄膜不同參數下的穿透率改變，並使用Color chart來量化模擬結果。第三部分為將可撓性電致色變顯示元件封裝，將進行其電路結構設計並製作完成。經由本實驗所量測得到的最佳薄膜沉積參數為2 V沉積電位條件沉積1分鐘，所得到之薄膜厚度約為400 nm，表面粗糙度介於7-12 nm間；氧化鎢薄膜最佳的著去色電位為2.5 V，其穿透率差在650 nm時達到80%，而著色效率可達100 cm2/coul；氧化鎢薄膜著色記憶保持能力為兩個小時，受到張應力固定彎曲半徑15 mm及10 mm記憶保持能力分別為1小時及4 分鐘、受壓應力固定彎曲半徑15 mm及10 mm記憶保持能力皆為1小時、受溫度效應的影響40℃及60℃記憶保持能力皆為1小時，著色記憶保持能力受到張應力彎曲次數會隨著次數增加而衰退，而受壓應力彎曲次數則因薄膜破裂已達其極限其著色記憶保持能力結果衰退致最差；漏電流也會因為張應力、壓應力及溫度效應的影響會使得漏電流越來越高。In this study, electrodeposition method was used to fabricate tungsten oxide electrochromic thin film. Tungsten oxide film was electrodeposited on plastic substrate to make the electrochromic display device. The experiments of this study were divided into three parts. The first part tested the best parameter of electrodeposition, coloration and bleaching, and discussed self-bleaching memory retention of electrochromic film under tension, compression, bending cycles, bending radius and temperature effect, and then investigated transmittance, delta transmittance and color efficiency, and observed surface morphology and roughness of films. Electronic properties of electrochromic film were tested by voltage-current. Second part, the color of films was simulated by light tools under different parameters, and the simulated results were defined by color chart. Last part, the packaged flexible electrochromic display device and the designed electric circuit were completed. The best parameter of voltage was 2V, and deposited time was 1 min in the experiment. The thickness of tungsten oxide was 400 nm, and the roughness of film was between 7 to 12 nm. The best parameter of coloration/bleaching voltage was 2.5 V. The delta transmittance and color efficiency of tungsten oxide film were 80% at 650 nm and 100 cm2/coul. The self-bleaching memory retention was 2 hours, and it was 1 hour and 4 minutes under the bending radius of 15 mm and 10 mm by tension, and it was both 1 hour under the bending radius of 15 mm and 10 mm by compression. The self-bleaching memory retention was both 1 hour at 40℃ and 60℃. The self- bleaching memory retention was declined with the increased bending cycles by tension, and it down to the worst because the film was broken under bending cycles by compression. The leakage current will be increased under the effect of tension, compression, temperature.