氧化銦錫（ITO）雖為優異的透明電極的材料，但具有以下缺點：材料稀有、製程容易造成材料浪費和機械性質硬脆、不易應用於穿戴式電子產品。近年來，許多研究顯示金屬網格電極在透光度和導電性表現已相當優異，是相當有潛力的ITO替代電極。本研究旨在開發一製程簡單、能於大氣下直接以雷射直寫技術快速製作金屬網格透明電極之技術。此技術，首先由草酸銀和丙二胺配置成新型金屬墨水，經雷射直寫製得銀網格電極，並研究其導電性、透光度和機械性質。 新金屬墨水的配置以草酸銀為前驅物，其優點為具有高銀含量，並能直接熱分解為金屬銀和二氧化碳，而無其它副產物。本研究再以乙醇和水作為溶劑來合成油墨，並研究水和乙醇在不同重量百分比配置下，通過雷射直寫技術進行圖案化後，對金屬銀線的表面形貌及電性影響。此種油墨穩定性佳，在室溫下放置 7 天仍維持無色透明狀態穩定性良好。實驗結果顯示，使用乙醇作為溶劑所配置之墨水，同一雷射直寫參數下，所製作出之銀線具有良好的表面形貌及電性，其電阻率可達塊材銀 1.8 倍且透光度大於 86%、平均厚度 800 nm 的金屬網格銀透明電極。 本研究之第二部份為金屬銀網格於在透明電極上的應用，將前述完成之銀電極崁入 PI(液態聚醯亞胺)基板中製作金屬軟性電極，並在 5000 次彎曲循環下，曲率半徑為 5 mm 進行機械性質測試，電阻的變化(ΔR /R0)在其原始值的 40％之內，仍在容許範圍之內。 ;Indium tin oxide (ITO) is an excellent transparent electrode material, but it has some disadvantages, such as it is rare in nature, its fabrication process is material wasting and poor in flexibility, and it is not applicable to wearable electronics. Recently, many studies have shown that metal mesh electrodes are quite excellent in light transmittance and conductivity, and are fairly potential ITO replacement electrodes. The main purpose of this research is to develop a new approach for rapidly fabricating metal mesh transparent electrodes using the technique of laser direct writing in the ambient environment. In this study, we first synthesize a new type of metal ink based on silver oxalate and propylenediamine. It is then subjected to the method of laser direct write to fabricate into a silver-based metal mesh electrode. Finally, the conductivity, transparency and mechanical properties of the electrode are examined. For metal ink configurations, the advantage of using silver oxalate as a precursor is its high silver content and which can be directly thermally decomposed into metallic silver and carbon dioxide without other by-products. In this study, we combine both ethanol and water as the solvent to synthesize inks, and the effects of the weight ratios between water and ethanol on the surface morphology and electrical properties of the resulting mesh were studied. The proposed ink has good stability and is stable in colorless and transparent state after being left in the ambient for 7 days. By a fixing set of laser writing parameters, the results indicate that the higher the content of ethanol in the solvent, the better surface morphology as well as higher conductivity on the resulting silver metal mesh. As the average thickness of the written meshes is of 800 nm and the transmittance of the electrode is up to 86% (@550 nm), the electrode’s resistivity is only 1.8 times that of the block silver. The second part of this study is to examine the electrode’s flexibility. The originally fabricated silver electrode on a glass substrate is embedded into a flexible PI (liquid polyimide) thin film to make the electrode flexible. Its flexibility is examined by a cyclely bending test which is executed 5000 cycles with a radius of bending curvature of 5 mm. The increase of relative resistance (ΔR/R0) was less than 40% of its original one and that was still within the allowable range.
