二六族半導體奈米材料之製備與其在有機光電元件之應用

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國立交通大學

應用化學研究所

博士論文

二六族半導體奈米材料之製備與其在有機光電

元件之應用

The Synthesis and Characterizations of II-VI Semiconductor

Nanomaterials and Their Applications in Optoelectronic Devices

研究生：周政玄 (Cheng-Hsuan Chou)

指導教授：陳登銘博士( Dr. Teng-Ming Chen)

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謝誌

受之於人而篤志向學，斯立者也；不受於人而惡勞好逸，斯敗者也。歲寒兮松柏而不凋，板蕩兮忠臣而無止；風雨兮雞鳴而不已，疾風兮群芥而強勁。讀聖賢之書，知處世之方些；誦詩詞之屬，了社會之亂也。能行鯉對，則受用與益無窮遠些；能知訓言，則有鑑與惕無一害也。孔曰己欲立達而也亦立達於人，孟曰憂患即生而安逸即亡。是故以此自我期許也！人生就像是馬拉松，當你選定了什麼樣的目標，就要努力的去付出與享受整個過程.一路走來, 苦樂酸甜 ~ 回首五年，承蒙諸多人的幫助。也因為王崇人教授，嚴謹周密的研究態度，啟發了我對學術研究的興趣。首先感謝恩師陳登銘教授，總是以虛懷若谷、無為而治的精神，帶領著實驗室，授與我莫大的發揮空間。論語說: 無為而治者，其舜也與。除了專業知識的吸收，也潛移默化的影響學生的性格與處世哲學。無論是在精神、思想上都有著深遠的影響。衷心感謝許千樹教授、孟心飛教授、刁維光教授長久以來，在有機合成、電子物理學，元件製作，與設備技術上的支援，都讓學生學習到精闢、專業的知識。也因為有這些年的訓練基礎，學生才能申請到獎學金前往 UCLA 學習。同時，感謝口試委員周卓煇教授、李紫原教授與李積琛教授，提供了許多寶貴意見以及思考方向，使得本論文可以更佳的完整。在清交，諸多實驗室的學長姊、學弟妹的幫忙。感謝許千樹老師家的勝雄、智文、衷核、小百學長們在前三年計畫的大力幫忙，學習到許多有機化學合成的知識。也感謝孟心飛、洪勝富老師家的諸多朋友：家銘，信榮，羽強，玄菱、建成、前後三屆的所有學弟們(啟宏、煥中、族繁不及記載)，在你們身上我學習到很多元件物理的知識。

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第四年的刁維光老師家：建仲學長、進興、思帆、在於 DSSC 上的技術合作和知識交流!! 感謝陳力俊老師家的李中陽同學，常常陪我在半夜討論關於奈米材料的點子，還有目前在翁啟惠院長門下服役的楊景舜同學，由於你分享我關於德國三明治的經驗，鼓舞我進而申請千里馬計畫。很感謝 Prof. Yang Yang 讓我體驗語學習不同的研究環境、教育文化與知識交流。在 UCLA 的 Dr Hong、Kwan、Vincent、Willam、Raymond、 Michelle、Sista and Anikt(族繁不及記載)。對於我最後一年來的聚合物太陽能電池的知識累積有著莫大的助益。最後感謝陪伴我四年過程中的實驗室夥伴: 已在業界打拼的拉斯卡、弘偉、曉雯、霹靂貓、婉甄，繼續留在交大當博後的德茹、靜萍、佳蓁，大家互相彼此學習成長，往後還需要認真負責的博班，健豪、彥吉、德文繼續幫忙實驗室。可愛的學弟妹們：93 巨澤、珮君、大小慧如、94 邱奕、峻魁、依蓉、柏儒、95 紫萍、mego、雅婷、怡君、曉萍、96 小拉、小 mo、阿蘊、R1、97 怡親、小 P、科科、七七、小韓、秀佩、毓傑，因為有你們實驗室變的很有活力，也持續的在螢光粉領域有著更卓越的突破。98 還有剛近來的新生: yoyo、琬妤、晏瑩、亘黼與阿專欣宜、阿題小花，大家後會有期，繼續打拼!! 自始自終，感謝親愛的家人，父親對我的知識與智慧的啟發，母親嚴格與善良的教育，同心協力的兄弟姊妹們，還有親愛的女友~ 婷文。因為你們一路精神與經濟上的大力支持，在我失落時，總是鼓勵我，使我能專心一致的學習，身為家中的一份子，懷著無比的感激~ 往後，我將持續盡我的全力奉獻於我們的家庭與社會。

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二六族半導體奈米材料之製備與其在

有機光電元件之應用

學生:周政玄

指導教授：陳登銘博士

摘要

本研究內容可分為兩大主軸:

第一主要探討半導體奈米材料之製備與應用，探討具不同發光波長量

子點之製備、特性鑑定與其於有機發光二極體之應用。第一章介紹無機半

導體量子點之發展歷史及文獻回顧，第二章敘述研究方法，第三章則探討

應用於發光二極體中所扮演之角色。本研究利用有機無機發光元件之優

點，進而以量子點為發光層材料，藉由有機無機混成之方式，利用量子點

粒徑調控，以獲得不同發光波長之量子點，進而製作單色光或混合白光發

光二極體。

第二研究探討另一種非放光性無機半導體材料之發展歷史與其應用

於聚合物太陽能電池中之可行性，同時研究其所扮演之角色與機構。

第四章則介紹以溫度控制方式於 ITO 電極上生長氧化鋅奈米結構，特殊其

山脊結構主要扮演著電子收集與傳遞，使得太陽電池填充因子大幅提升進

而增進電池效率。相較於兩階段製備之一維奈米結構或表面再修飾法，此

方法可簡單地控制奈米結構，進而可應用於倒結構(inverted)聚合物太陽

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能電池。

第五章主要介紹非晶相氧化鋅之製備與其應用於聚合物太陽能電池

之可行性，並設計與結合不同 p 型材料，製備出具有良好電性、化學性質、

物理性質之中間介面層，進而首次製作與發表高效率(~5.1%)倒結構串接

(inverted tandem)太陽能電池。

第六章則總結本論文之研究成果與未來研究目標，本研究已成功將無

機半導體材料結合有機電激發光元件，發光量子點取代發光層以增加元件

穩定性與光色單一性。另一項研究成果則在於無機奈米結構對於聚合物太

陽能電池影響之了解。並結合不同材料 P-N 材料之特性，進而了解多層聚

合物太陽能電池之可行性。

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Abstract

This thesis is divided into two major sections. The first part is being the synthesis

and characterization of the quantum dot (QD), followed by the fabrication and character-

ization of the resulting QD-LEDs. The fabrication of QD-LEDs consists of synthesizing the

semiconductor nanocrystals (NCs) with the desired properties followed by the incorporation

of these NCs into PLED based device structures. Chapter 3 introduces the semiconductor

CdSe/ZnS and discusses in detail the synthesis, characterization, and properties, as well as

how the application CdSe/ZnS QDs into device. The fabrication and EL characterization of

a white-emitting hybrid QD-LED by integrating core-shell CdSe/ZnS QDs acting as a

yellow emitter and polyfluorenes as the blue emitter in a multilayered structure.

The second part is being the synthesis and characterization of the zinc oxide (ZnO)

materials, followed by the fabrication of the resulting ZnO based polymer solar cells.

Chapters 4 discuss the design of a ZnO nano-ridge structured film that can be used as an

electron collection layer in an inverted polymer solar cell. The ZnO nano-ridge structure was

formed by a simple sol-gel process using a ramp annealing method. As the solvent slowly

evaporated due to the low heating rate, there was sufficient time for the gel particles to

structurally relax and pile up, resulting in a very dense and undulated film. This film provided an effective charge selection layer and an increased interfacial area for charge collection.

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VII

Chapter 5 discusses the study of a highly efficient tandem polymer solar cell with

inverted polarity. The optically transparent interlayer, consisting of a molybdenum trioxide

(MoO3) layer and an amorphous ZnO, serves as the interconnecting layer facilitating charge

recombination between the bottom and top sub-cells. The ZnO layer, prepared by a low

temperature process, provides a dense layer for electron collection and a barrier against

solvent from dissolving the under layer. The leads to the high photovoltaic performance in

both single and tandem inverted solar cells. Under simulated solar illumination of AM 1.5G

(100 mWcm-2), the device exhibited a Jsc = 7.8 mAcm-2, Voc = 1.20 V, FF = 0.54, and η =

5.1%. This is the first study reach over 5% in the successful demonstrated in inverted

tandem solar cell. Chapter 6 is the achievement and summary for this thesis and future

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VIII

Chapter 1: Introduction

1.1 Hybrid Organic/Inorganic Light Emitting Devices 1

1.1.1 Colloidal Semiconductor Nanocrystals 1

1.1.2 Organic Light Emitting Devices 8

1.1.3 Historical Perspective of hybrid QD-LED 9

1.2 Polymer Bulk Heterojunction Solar Cells 14

1.2.1 The Bulk Heterojunction Concept 14

1.2.2 Device Operation Principle 16

1.3 Motivation 19

1.4 Thesis organization 20

Chapter

2:

Experimental

Methods

2.1 Materials 22

2.2 Equipments 22

Chapter 3: Hybrid White-Light Emitting QD-LED

3.1 Background and Motivation 25

3.1.1 Blend Method 25

3.1.2 Bonding Method 27

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3.2 Device Structure Design and Experimental Details 30

3.3 Results and Discussions 33

3.4 Summary and Conclusions 40

Chapter 4 :

ZnO Nano-Ridge Structure and Its Application In Inverted

Polymer Solar Cell

4.1 Background and Motivation 41 4.2 ZnO-Based Inverted Polymer Solar Cell 44

4.2.1 ZnO Materials and Device Performance 44 4.2.2 Device with Modified ZnO 47 4.2.3 Device with ZnO Nanostructure 48 4.3 Device Structure Design and Experimental Details 51

4.4 Results and Discussions 52

4.5 Summary and Conclusions 59

Chapter 5: Highly Efficient ZnO-Based Inverted Tandem Polymer Solar

Cell

5.1 Back groundand Motivation 60 5.2 Recent developments 63

5.3 Device Structure Design and Experimental Details 68

5.4 Results and Discussions 71 5.5 Summary and Conclusions 83

Chapter 6 : Conclusions and Future Prospects

6.1 Thesis conclusions 84

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6.2.1 Hybrid White-Light Emitting QD-LED 85 6.2.2 ZnO Nano-Ridge Structure and Its Applications 85 6.2.3 Efficient ZnO-Based Inverted Tandem Polymer Solar Cell 86

Curriculum Vitae 87