氧化銦錫透明導電薄膜之製備及燒結特性研究

Abstract

隨著電子產品的普及，透明導電膜被廣泛利用在各項產品中，如太陽能板、顯示面板等，都需要透明導電膜及透明導電玻璃作為元件。目前產業界中廣泛使用的透明導電膜以氧化銦錫作為原料，氧化銦錫具有良好的透光性以及導電性，為相當優秀的材料，利用濺鍍方式在玻璃基材上沉積出透明導電薄膜。然而，以上製程面臨許多挑戰：銦為稀有金屬，地球含量有限並且有枯竭的可能，並且濺鍍製程需要的設備條件較高，間接造成氧化銦錫透明導電薄膜價格居高不下。因此，近年有氧化銦錫回收製程的興起，將氧化銦錫透明導電玻璃重新回收後再利用。 本研究提出了一種利用氧化銦錫回收製備透明導電薄膜及圖樣並應用於印刷電子元件的技術。首先，將氧化銦錫由廢棄面板中回收，並且純化及球磨減小粒徑至約50 nm，並加入適當分散劑及黏合劑製成分散水力粒徑約145 nm導電墨水，結合刮刀塗布技術製為透明導電薄膜。利用光燒結技術可以有效的避免軟性高分子基材PET於燒結過程中損壞，1000焦耳分為4波段，並且進行4次多段燒結中間間隔時間3秒為最佳的參數，可以使燒結過後的導電薄膜片電阻下降100倍，達到約500 Ω/sq，並且透光度高於90%。製備出的透明導電PET可以承受多次撓曲、並且作為全透明電雙層電容，抑或結合噴墨印刷技術製備為透明導電線路使用。總而言之，本研究提出了一種新的回收氧化銦錫再製備為透明導電薄膜的方法，並且為回收氧化銦錫生命週期再延續技術方面拓展了一條嶄新的道路。

Transparent conductive films (TCFs) are extensively used in various products, such as solar cell module, display panel. With good optical transparency and electrical conductivity, indium tin oxide (ITO) is the most-used material for fabricating TCFs. However, because of the high demand and the scarcity of indium, TCFs are very expensive and indium exhaust problem also emerges recently. Therefore, there are researches which focus on ITO recycled process and further applications. In this study, we combined ITO recycling process and printing technologies to manufacture transparent conductive films and patterns for flexible printed electronics applications. First, ITO was recycled from waste display panel, and further purification and size reduction process were applied to form ITO nanoparticles with primary particle size roughly 50 nm. Dispersant and binder were added to formulate conductive nanoparticle ink with hydraulic size roughly 145 nm. Then, blade coating was applied to form transparent conductive film on the substrate. Intense pulsed light (IPL) sintering with different parameters were tested to set the best sintering condition to increase the conductivity of TCFs. The best parameter for sintering was 1000 J divided into four small peaks (250 J each) repeated for four times pulses with 3 s time interval. ITO TCFs on PET substrate showed good conductivity (500 Ω/sq) and transparency (>90 %). Also, the TCF could withstand multiple times bending test with small sheet resistance change. TCFs could also applied as electrode for electrical double layer capacitor. Furthermore, by inkjet printing technology, transparent conductive patterns could also be fabricated without traditional etching process. In summary, this research provides a new guideline for TCFs manufacturing with recycled ITO and provides a new way for reusing end-of-life display panel for transparent conductive films and patterns applications.