| 摘要: | 透明導電薄膜(Transparent conductive films, TCFs) 是指具有良好導電性與透光性的薄膜。隨著 消耗性電子的蓬勃發展，TCFs 的需求有增無減，已是重要的關鍵材料。現今商用的TCFs 主要是含 金屬之透明導電氧化物(Transparent conducting oxides, TCOs)，過去20 年以銦錫氧化物 (Indium Tin Oxide, ITO)與摻雜氟(Fluorine)的氧化銦(Fluorine-doped Tin Oxide, FTO)最為普遍。但銦與氟有毒對 環境有害，且銦稀有，隨著使用量增加存量逐漸減少，價格愈來愈高；同時， ITO 易脆，不適合 可撓曲元件。因此，近年來有許多開發新TCFs 的研究，特別著重低成本、可低溫製程與可適用於 高撓曲。在TCOs 中，ZnO 參雜Al，即AZO，廣受重視，因其導電性與透光性可與ITO 媲美、鋅 礦來源無虞、且除了鍍膜製程外，也可以溶液型態製作，如溶膠凝膠法等。另外，近年來發現的石 墨烯，具有良好導電性、在薄厚度時透光性良好、其組成物碳易與有機材料相容與優異撓曲性質， 也使它成為極具潛力的TCFs 材料。 本三年期之計畫旨在開發以雷射退火製作並圖案化 AZO 與石墨烯透明電極薄膜於塑膠基板或 其他薄膜材料上面，並實際應用於有機電子與光電元件上。其創新處在AZO 膜由AZO 奈米粒子退 火形成而石墨烯膜則由石墨烯氧化物還原，兩者皆可使用溶液成膜，配合雷射，全程可在大氣環境 中、室溫下，形成具特定圖案之透明電極。計畫第一年是開發雷射退火製程與薄膜特性檢測，第二 年為薄膜圖案化新製程技術開發，第三年則將圖案化之透明電極製作於以軟性基板為基礎之有機電 子與光電元件上，且配合圖案化技術之使用，提升元件性能，目標元件有：高分子發光二極體、有 機薄膜電晶體與有機太陽能電池。雷射可單獨或結合簡易光罩對特定區域材料作處理，亦可經由掃 瞄方式作大面積處理，此技術也可於退火過程中同時進行圖案化，因此具簡易、低成本、適於低溫 製程、易與目前開發中的印刷式製程 (如Roll-to-Roll 製程) 結合之優勢。 雷射退火與圖案化過程可在一個或數個雷射脈衝期內完成。基礎學理方面，在極短時間內，從 材料吸收光開始、經性質改變、到退火完成形成連結良好之AZO 與石墨烯還原透明電極，這中間 包含了複雜的光吸收、熱傳、相變化、光還原、高分子薄膜固、液之塑性變形與流變等諸多行為， 機制相當多元，詳細之機理仍有許多未解之處，特別在動態變化過程。因此，除了在成膜完成後對 薄膜表面之形貌、光、電特性、及結構等靜態特性作檢測外，在基礎學理的探討上，本計畫也將創 新以即時薄膜表面特性觀察方式，進一步瞭解成膜過程之動態變化。 應用方面，雷射薄膜退火與圖案化是一關鍵核心技術，除了透明電極，更可廣泛地應用於其他 薄膜材料。在學理方面，成膜與圖案化動態過程之機理也極富探討價值。透過這個計畫，期望更進 一步開發核心技術與讓基礎學理研究生根、也能培養學子在這個核心領域之能力與視野。 ; Transparent conductive films, TCFs, are thin films with both good conductivity and transparency. With the market blooming of consumer electronics, the demanding of TCFs is rapidly increased. It is no doubt at all that TCFs now become one of the key materials for the electronic and optoelectronic industries. Currently, the commercially available TCFs are mainly from the transparent conducting oxides, TCOs. For the past two decades, tin doped indium oxide (ITO) and fluorine doped tin oxide (FTO) are essentially preferred in industry. However, toxic indium and fluorine might be the cause of disquiet to the environment and the indium element is rare and expensive. Besides, the mechanical failure of brittle oxide coatings is serious that limits their applications to flexible devices. As a result, many attempts have been made to the potential substitute to these well-recognized materials. The Al doped zinc oxide (AZO) thin film is considered as an alternative. Because its conductivity and transparency are comparable to ITO, the zinc source is abundant, and it is also solution processible at room temperature. For its excellent conductivity and good transparency, another very promising alternative is graphene. In addition, carbon, the composition of graphene, is intrinsically highly compatible with organic materials and has superb flexibility. Hereby the objective of this three-year termed proposal is aimed to develop laser annealing and patterning techniques for fabricating patterned AZO and graphene TCFs on flexible substrates or upon various organic thin films for the fabrication of organic devices. The main features of this approach are: the resulting AZO and graphene films are from soluble AZO nanoparticles and graphene oxides, respectively; and, the whole fabrication course is executable at room temperature and in the ambient. The proposal’s yearly objective is described as follows: the focus in the 1st year is on developing the laser annealing and patterning techniques for fabricating the two targeted TCFs and characterizing the resulting films; for the 2nd year, the aim is to deliver new schemes for laser patterning the TCFs; and, finally in the 3rd year, the developed techniques are utilized to pattern the TCFs for the three interested organic devices – polymer light emitting diodes, organic thin-film transistors and organic photovoltaics. Laser, itself, or simply integrated with a mask, is a very suitable tool for local material processing and, through the technique of optical scanning, it is able to execute a large-scale treatment as well. Additionally, both the annealing and patterning can be simultaneously accomplished within a single laser shot. This method thus takes the advantages of straightforwardness, low cost, applicability to low temperature fabrications as well as compatibility to the emerging printing-based fabrication methods. The laser annealing and patterning can be accomplished within a single or several laser pulses. Within such a short duration, fundamentally, it involves, at least, the stages of laser absorption, laser induced reduction, heat transfer in a multilayered structure, phase transitions, merging and growing of nanoparticles, as well as the polymer films’ deformation and variation in rheological properties. Understanding of such a complex transport phenomena within an ultra short period of time essentially presents challenges. The resulting thin film’s morphology, mechanical, optical and electrical properties are characterized by the often-used thin-film characterization techniques. Besides, this study proposes a new experimental arrangement to investigate the evolution of the film formation through a real-time surface probing technique. In addition to the TCFs, laser annealing and patterning are core techniques applicable to a variety of thin films as well. The proposed subject thus has high application potential and it also presents a wealth of fundamentals to explore. It is hoped, through this project, the fundamentals can be further addressed and several new patterning techniques can be developed. ; 研究期間 10208 ~ 10307 |
