플라즈마 및 후막공정을 이용한 광전기 화학셀 제작 = Fabrication of photoelectrochemistry cell by plasma and thin film process

다국어 초록 (Multilingual Abstract)

A layer of TiO2 thin film less than ∼200nm in thickness, as a blocking layer, was deposited by 13.56 MHz radio frequency magnetron sputtering method directly onto the anode electrode to be isolated from the electrolyte in dye-sensitized solar cells (DSCs). This is to prevent the electrons from back-transferring from the electrode to the electrolyte (I-/I3-). The presented DSCs were fabricated with working electrode of F:SnO2(FTO) glass coated with blocking TiO2 layer, dye-attached nanoporous TiO2 layer, gel electrolyte and counter electrode of Pt-deposited FTO glass. The effects of blocking layer were studied with respect to impedance and conversion efficiency of the cells. The ,electrochemical impedances of DSCs using this electrode were R1: 22.1, R2: 40.6, R3: 23.2 and Rh: 26.2Ω. The R2 impedance related by electron movement from nanoporous TiO2 to TCO showed lower than that of normal DSCs. The photo-conversion efficiency of prepared DSCs was 6.74% (Voc: 0.715V, Jsc: 12.93 mA/cm2, ff: 0.73) and approximately 1.17% higher than general DSCs sample. In addition, From the impedance profiles, the samples at > 60 nm show low Rh properties, which were about 80% for the samples at < 40nm. A clear decrease with the increase in the TiO2 layer thickness can be recognized for Rh. The maximum efficiency of the DSCs sample with a TiO2 blocking layer of 60 nm thickness was ~6.74% (Voc: 0.715V, Jsc: 12.93 mA/cm2, ff: 0.73), while the value of the sample of 20 nm thickness was ~5.82% (Voc: 0.707 V, Jsc: 12.12 mA/cm2, ff: 0.68). The maximum efficiency of 6.74% is to be enhanced by 1.17% compared to the general cell without blocking layer. Furthermore, the ff is related to the series resistance, Rs, of the cells and Voc is related to the potential difference between the TiO2 and the electrolyte in the cell. This indicates that the conductivity and porosity of the TiO2 layers slightly affect the series resistance of the cell and the Fermi level of the TiO2 electrode. On the other hand, Jsc and h show distinct variations with TiO2 blocking layer thicknesses. Jsc is the most influential factor on the cell efficiency, although many other factors in combination can affect the cell efficiency. From the results, the values of Jsc at > 60 nm are higher compared with those at < 40nm. The variation of Jsc can be explained as follows. In DSCs, Jsc is closely related to electron generation, electron transport, and electron diffusion. The Rh of the TiO2/FTO layers is the lowest at > 60nm. The low Rh can improve the electron transport and mobility; therefore, it increases the Jsc.
electrochemiluminescence (ECL) cell using nanocrysralline TiO2 electrode and Ru(Ⅱ) complex (Ru(bpy)32+) is fabricated for low-cost high-efficient energy conversion device application. The nanocrysralline TiO2 layer (∼10µm thickness) with large surface area (∼360m2/g) can largely inject electrons from nanoporous TiO2 electrode and allows the oxidation/reduction of Ru(Ⅱ) complex in the nanopores. The cell structure is composed of a glass/ F-doped SnO2(FTO)/ porous TiO2/ Ru(Ⅱ) complex in acetonitrile/ FTO/ glass. The nanocrysralline TiO2 layer is prepared using sol-gel combustion method. The ECL efficiency of the cell consisting of the porous TiO2 layers was 250 cd/W, which was higher than that consisting of only FTO electrode (50cd/W). The nanoporous TiO2 layers was effective for increasing ECL intensities.

목차 (Table of Contents)

• 표목차 iv
• 그림목차 v
• Ⅰ. 서론 1
• Ⅱ. 이론적 배경 3
• 1. 방전 이론 3
• 1.1 하전입자 및 입자군의 발생 및 소멸 3
• 1.2 Paschen 법칙 5
• 1.3 RF Glow Discharge 9
• 1.3.1 교류 방전을 사용하는 효율성과 이유 9
• 1.3.2 고주파 방전의 효율 11
• 1.3.3 Matching network 13
• 1.4 Sputtering 15
• 1.4.1 스퍼터링법에 의한 증착 과정 18
• 1.4.2 박막형성 과정 19
• 1.4.3 스퍼터율(sputter yield) 20
• 1.4.4 마그네트론 스퍼터링법 21
• 1.4.4.1 자계의 이용 22
• 1.4.4.2 구조의 개선 23
• 2. 태양전지(Solar Cells)의 원리 및 주요 이론 25
• 2.1 태양전지의 기본 원리 및 기초 이론 25
• 2.1.1 광자(Photon) 25
• 2.1.2 광전효과(Photon Electric Effect) 27
• 2.1.3 The Solar Spectrum 28
• 2.1.4 Air Mass 29
• 2.2 태양전지의 광전 특성 32
• 2.2.1 태양전지의 전류-전압 곡선 특성 32
• 2.2.2 태양전지의 곡선 인자와 변환 효율 34
• 3. 염료 감응형 태양전지(DSCs)의 원리 및 주요 기술 37
• 3.1 염료 감응형 태양전지(DSCs)의 재료 37
• 3.1.1 전도성 투명전극 37
• 3.1.2 나노입자의 다공질 TiO2 38
• 3.1.3 염료 42
• 3.1.4 전해질 43
• 3.1.5 상대전극 44
• 3.2 염료 감응형 태양전지(DSCs)의 기본 원리 46
• 3.2.1 DSCs의 구조 및 작동원리 46
• 3.2.2 산화물 반도체 전극과 전해질 계면 반응 48
• 3.2.3 산화물 반도체 전극과 염료 계면의 반응 49
• 3.2.4 산화물 반도체과 투명 전극 계면 51
• 4. 전기화학 발광 (ECL) 52
• 4.1 화학발광 (Chemiluminescence, CL) 52
• 4.2 Ru(bpy)32+의 전기화학 발광 (Electrochemiluminescence, ECL) 54
• Ⅲ. 실험 방법 58
• 1. 나노입자의 다공질 TiO2 powder의 제작 58
• 1.1 소결 온도에 따른 TiO2 powder의 제작 60
• 1.2 Ketjen Black 첨가량에 따른 TiO2 powder의 제작 61
• 2. 염료 감응형 태양전지의 요소 재료의 준비 62
• 3. TiO2 차단막을 사용한 염료감응 태양전지 제작 65
• 3.1 rf magnetron sputtering 법을 사용한 TiO2 박막 제작 65
• 3.2 TiO2 박막을 사용한 염료감응 태양전지 제작 68
• 4. Nanoporous 이산화티타늄 전극 기반의 전기화학형 발광(ECL) 셀 제작 72
• 4.1 전기화학형 발광 (ECL)소자의 구조 및 원리 72
• 4.2 Ru(bpy)32+ 기반 발광 전해질 제작 75
• 4.3 Nanoporous 이산화티타늄 전극 제작 77
• 4.4 전기화학형 발광(ECL) 셀의 제작 79
• Ⅳ. 실험 결과 및 고찰 81
• 1. 다공질 광전극의 결정 구조의 특성 81
• 1.1 소결온도에 따른 TiO2 powder의 결정 구조 81
• 1.2 Ketjen Black 함량에 따른 TiO2 powder의 결정 구조 88
• 2. TiO2 차단막의 특성 고찰 93
• 2.1 TiO2 차단막을 사용한 셀과 일반 셀의 비교 분석 93
• 2.2 TiO2 차단막 두께에 따른 특성 고찰 97
• 3. Nanoporous 이산화티타늄 전극 기반의 ECL 특성 고찰 102
• Ⅴ. 결론 108
• 참고문헌 110
• ABSTRACT 115
• (감사의 말씀) 117