금속 칼코게나이드의 합성과 콜로이드 나노입자 개질 및 광전류 소자에 응용
Fabrication of Metal Chalcogenide and Their Application for Colloidal Nanocrystal Modification and Photocurrent Device.
- 주제(키워드) metal chalcogenide , nanocrystal Modification , Photocurrent , Solar Cell
- 발행기관 아주대학교
- 지도교수 김상욱
- 발행년도 2015
- 학위수여년월 2015. 8
- 학위명 박사
- 학과 및 전공 일반대학원 분자과학기술학과
- 실제URI http://www.dcollection.net/handler/ajou/000000020564
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
이 박사학위 논문의 주제는 새로운 형태의 금속 칼코게나이드를 합성하여 표면 개질, 무기 리간드, 태양 전지, 광전 소자에 응용하는 것이다. 금속 칼코게나이드는 단분자, 나노입자, 나노와이어등의 다양한 형태로 합성되었다. Na2Se2와 M2Se2(ClO4)2 (M=Mn, Zn, Sn)은 단분자 형태로 합성되어 무기리간드로 응용되었다. FeS2는 안정한 나노입자로 합성되어 BHJ 무기물 태양전지에 응용되었다. 무기물 태양전지는 기존의 태양전지보다 안정성이 높았다. Sb2Se3 나노와이어는 새로운 방법으로 합성되었으며, 단점인 전도성을 개선시키기 위해 새로운 방법이 도입되었다. 1 장에서는 알칼리 금속 칼코게나이드 Na2Se2의 새로운 응용분야를 찾았다. Na2Se2는 기존 합성법을 약간 변형하여 순수한 Na2Se2를 합성하였다. Na2Se2는 나노입자의 종류에 따라 다른 작용을 보인다. PbS나노입자와 반응하면 PbS/PbSe 코어/쉘 나노입자로 만드는 음이온 교환 전구체로 작용하며, Ag 나노입자와 반응하면 Ag2Se 나노입자로 만드는 금속 셀레나이드 전구체로 작용하며, FeO 나노입자와 반응하면 FeO의 표면의 유기리간드를 제거하는 무기리간드로 작용한다. 2장에서는 새로운 양이온 무기리간드 M2Se2(ClO4)2 (M = Mn, Zn, Sn)를 합성하였다. 양이온 무기리간드로 치환된 나노입자와 음이온 무기리간드로 치환된 나노입자를 정적기적인 인력으로 결합하여 새로운 3차원 나노구조물질을 만들 수 있는 장점을 가지고 있다. 양이온 무기리간드로 치환된 나노입자는 휘발성이 거의 없어 소자에 적용가능한 나노입자 박막을 만들 수 있다. 3장에서는 FeS2와 CdSe 나노입자를 이용하여 donor?acceptor (D?A) bulk heterojunction (BHJ) Inverted 태양 전지를 제작하였다. 무기 BHJ 나노복합체는 넓은 흡수 영역과 type II 밴드갭 형태 에서 주개-받개쌍을 통한 효율적인 전하 분리를 보였다. FeS2 나노입자는 친환경적이고 자연계에 많이 존재하며 용액공정으로 태양전지 제작이 가능하다. 제작된 태양전지는 일반적인 태양전지보다 안정성이 뛰어나다. 4장에서는 CdO 나노입자는 2-6족 산화물 반도체로 2.27 eV 의 밴드갭과 0.55eV의 간접 밴드갭을 가지고 있다. CdO는 단순한 암염형 구조, 높은 전하 이동도, 높은 전기 전도도를 가지고 있어 투명전극으로 이용 가능하다. 우리는 단순한 합성방법으로 크기와 모양이 조절되는 CdO 나노입자를 합성하였다. 5장에서는 Sb2Se3는 좁은 밴드갭과 높은 화학적 안정성, 높은 제벡상수를 가지고 있어 광전소자, 열전소자 및 태양전지에 응용이 가능하다. 하지만 Sb2Se3의 전기 전도도가 매우 낮아 응용이 제한되고 있다. 이러한 문제를 해결하기 위해 두께가 조절되는 Sb2Se3 나노와이어와 Ag2Se가 붙어 있는 Sb2Se3나노와이어를 합성하였다. 두께가 조절되는 나노와이어의 광전류를 측정한 결과, 나노와이어의 두께와 흐르는 전류사이에서 비선형적인 증가를 발견하였다. 100nm 두께를 가지고 있는 Sb2Se3 나노와이어의 photosensitivity factor를 측정한 결과 낮은 인가전압에도 불구하고 75라는 높은 수치가 나왔다. Ag2Se가 붙어 있는 Sb2Se3나노와이어의 광전류를 측정한 결과 Sb2Se3나노와이어 대비 암전류는 50배, 광전류는 7배 증가하였다.
more초록/요약
The main contents of the doctoral thesis are the fabrication of new structured metal chalcogenide and their specific application including surface modification, inorganic ligand, photovoltaic cell and photocurrent device. Metal chalcogenides were synthesized in a variety of dimensions such as single molecule, nanoparticles, and nanowire. Novel synthetic routes to single molecule inorganic ligand such as Na2Se2 and M2Se2(ClO4)2, positive charge inorganic ligand and new applications area are presented. The synthesis of stable FeS2 nanoparticle is discussed. Inverted solar cells are developed using FeS2 and their long-term stability of all-inorganic BHJ FeS2 solar cells is measured. The new synthesis method of Sb2Se3 nanowire is developed using hot-injection method. To improve the electrical conductivity of Sb2Se3 nanowire, two kinds of nano-structured materials is addressed. In Chapter 1, New application areas using very simple alkali metal chalcogenide, disodium diselenide (Na2Se2), has been developed. Prepared alkali metal chalcogenides(disodium diselenide, Na2Se2) according to the literature with slight modification are acting as an anionic exchange precursor(PbS to PbS/PbSe), Se precursor for metal selenide nanoparticles(Ag to Ag2Se), and MCCs(FeO-MCCs) depending on the type of colloidal nanoparticles. Every reaction can be performed at ambient temperature. In Chapter 2, Novel positive charge inorganic ligand in the form of M2Se2(ClO4)2 (M = Mn, Zn, Sn) is developed. It has tremendous application potential about three-dimensional nanostructure formation due to the positive and negative charge of electric force using the positive and negative charge inorganic ligand capped nanoparticles. The Mn2Se22+ capped CdSe have low volatile matter measured by TGA, it can be a great advantage of fabrication of film using colloidal nanoparticles for device application. In Chapter 3, Inverted solar cells were developed using a donor?acceptor (D?A) bulk heterojunction (BHJ) of iron pyrite nanocrystals (FeS2 NCs) and cadmium selenide quantum dots (CdSe QDs). The all-inorganic BHJ nanocomposites showed broad-range absorption and effective dynamics of charge dissociation and transfer through bi-continuous D?A interactions under a type II band-offset system. Our findings suggest the potential of FeS2 NCs as an environmentally benign, earth-abundant material for solution-processed photovoltaic applications. The merits of an FeS2?CdSe D?A BHJ system with an inverted device architecture and its long-term stability are addressed. In Chapter 4, Cadmium oxide(CdO), which are a II-VI binary oxide semiconductor with a direct bandgap of 2.27 eV and an indirect bandgap of 0.55 eV in the bulk state, is a promising candidate for a transparent conducting oxide material because it has a simple rock-salt crystal structure, high carrier mobility, and high conductivity. Although CdO have numerous potential applications, very less research has been carried out on the synthesis and application of these nanocrystals. We report the simple synthesis of colloidal CdO nanocrystals with various sizes and shapes. In Chapter 5, Due to its direct and narrow band gap, high chemical stability, and high Seebeck coefficient (1800 μVK-1), antimony selenide (Sb2Se3) has many potential applications, such as in photovoltaic devices, thermoelectric devices, and solar cells. However, research on the Sb2Se3 materials has been limited by its low electrical conductivity in bulk state. To overcome this challenge, we suggest two kinds of nano-structured materials, namely, the diameter-controlled Sb2Se3 nanowires and Ag2Se-decorated Sb2Se3 nanowires. The photocurrent response of diameter-controlled Sb2Se3, which depends on electrical conductivity of the material, increases non-linearly with the diameter of the nanowire. The photosensitivity factor (K = Ilight/Idark) of the intrinsic Sb2Se3 nanowire with diameter of 80?100 nm is highly improved (K = 75). Additionally, the measurement was conducted using a single nanowire under low source-drain voltage. The dark- and photocurrent of the Ag2Se-decorated Sb2Se3 nanowire further increased, as compared to that of the intrinsic Sb2Se3 nanowire, to approximately 50 and 7 times, respectively.
more목차
Acknowledgement i
Abstract iii
Table of Contents vi
List of Figures x
PART 1. Introduction 1
1. Nanotechnology 2
2. Definition of Metal Chalcogenide 8
2.1. Transition metal chalcogenide 9
2.2. Main group chalcogenide 10
2.3. Alkali & alkali earth metal chalcogenide 11
3. Application of Metal Chalcogenide 14
3.1. ion exchange reaction 14
3.2. Inorganic ligand 15
3.3. Energy conversion device 19
4.References 21
PART 2. Metal Chalcogenide Single Molecule 25
Chapter 1. Disodium Diselenide in Colloidal Nanocrystals: Acting as an Anion Exchange Precursor, Metal Selenide Precursor, and Chalcogenide Ligand. 26
1. Introduction 27
2. Experiment section. 30
2.1. Materials 30
2.2. Synthesis of Na2Se2 30
2.3. Synthesis of nanoparticles 30
2.3.1. PbS nanoparticle 30
2.3.2. Ag nanoparticles 31
2.3.3. FeO nanoparticles 31
2.4. Reaction of nanoparticles with Na2Se2 32
2.5. Measurement 33
3. Results and discussion 34
4. Conclusions 48
5. References 49
Chapter 2. Positive Charge Inorganic Ligand with Colloidal Quantum dot 51
1. Introduction 52
2. Experiment section 54
2.1. Synthesis of Na2Se2 54
2.2. Synthesis of Mn2Se2(ClO4)2 54
2.3. Synthesis of nanoparticles 54
2.3.1. CdSe nanoparticle 54
2.3.2. CdSe/CdS nanoparticle 55
2.3.3. InP nanoparticle 55
2.3.4. InP/ZnS nanoparticle 56
2.3.5. PbS nanoparticle 56
2.4. Reaction of nanoparticles with M2Se2(ClO4)2 52
2.5. Measurement 57
3. Results and discussion 58
4. Conclusions 69
5. References 70
PART 3. Metal Chacogenide Nanoparticles 73
Chapter 3. Solution-processed inverted solar cells using an inorganic bulk heterojunction of iron pyrite nanocrystals and cadmium selenide quantum dots with a polymeric hole-transport medium 74
1. Introduction 75
2. Experiment section 78
2.1. Synthesis of FeS2 NCs 78
2.2. Synthesis of CdSe QDs 78
2.3. Device fabrication 79
2.4. Characterization. 80
3. Results and discussion 81
4. Conclusions 96
5. References 97
Chapter 4. Fabrication of Cadmium Oxide Nanocrystals with Size and Shape Control 101
1. Introduction 102
2. Experiment section 104
3. Results and discussion 105
4. Conclusions 110
5. References 111
PART 4. Metal Chacogenide Nanowire 113
Chapter 5. Diameter-Controlled and Surface-Modified Sb2Se3 Nanowires and Their Photodetector Performance 114
1. Introduction 115
2. Experiment section 117
2.1. Materials 117
2.2. Synthesis of intrinsic Sb2Se3 nanowires 117
2.3. Synthesis of Ag2Se decorated Sb2Se3 nanowires cid 117
2.4. Photo-device fabrication 118
2.5. Characterization 118
3. Results and discussion 120
4. Conclusions 142
5. References 143
PART 5. Conclusions 146
1. Conclusions 147
Abstract in Korean 149
List of Publication and Patent 152
