臺灣博碩士論文加值系統

在本研究中我們建構一個混合式異質接面結構有機導電高分子太陽電池的理論模型，其中包含光子在活化層被受體吸收、光激子的移動、電子電洞的分離、電子(電洞)在活化層內的漂移和邊界上的載子熱注入。利用數值方法解卜瓦松與連續體方程式，再藉由布朗模型描述電子與電動的解離，藉此來描述導電高分子太陽能電池的放電表現，而後更進一步的將其拓展到表面改質金屬氧化物與導電高分子混掺的太陽能電池。我們發現在表面改質金屬氧化物與導電高分子混掺太陽能電池中，可以有效的把電荷轉移態與自由載子間的解離速率大幅提升，造成二氧化鈦表面改質與導電高分子混摻太陽能電池的填充因子(fill factor)與開環電壓(open circuit voltage)比純有機混摻太陽能電池大的多。但與純有機系統相較，其光激子轉變為電荷轉移態的效率沒有來的好(~100%)，應是其光電轉化效率較低的主因。

In this thesis, we develop a theoretical model for modeling the current-voltage characteristics of surface modified TiO2/P3HT hybrid solar cells. This model considers the adsorption of photons, the excitation and transport of excitons, the formation of polaron, and its dissociation to free charge carriers. The transport of free charge carriers is governed by the poisson and continuity equations.

We found that the surface modifier enhances the efficiency of polaron dissociation. The efficient polaron dissociation can result in high fill factor and high open circuit voltage. However, compared with the organic polymer solar cells, there is a significant loss of excitons before they can be converted to poalrons in surface modified TiO2/P3HT solar cell. This is the main reason for the lowered efficiency of the surface modified TiO2/P3HT solar cells.

致謝 I
中文摘要 II
Abstract III
List of Figures VI
List of Tables VIII
1. Introduction 1
1.1 Background 1
1.2 Species of Solar Cells 4
1.3 Comparison of Different Structures of Organic Solar Cells [9, 10] 9
1.4 Metal Oxides and Conducting Polymer Bulk Hetero- junction Solar Cells 11
1.5 Surface Modified Metal Oxides and Conducting Polymer Bulk Heterojunction Solar Cells 12
1.6 The I-V Curve and Efficiency Coefficient 17
1.7 Review of Literatures 19
2. Theoretical model 23
2.1 From Photons to Excitions 23
2.2 Exciton Transfer 29
2.3 From Polaron to Free Charges 29
2.4 Free Carrier Transport 34
2.5 Boundary Conditions 36
2.6 Additional Resistances in the Device 44
3. Simulation Method 46
3.1 Central Finite Difference Method for Continuity Equations and Poisson’s Equation 47
3.2 Gummel- Scharfet Approximation Method 49
3.3 All The Governing Equations With Finite Difference Operating 50
3.4 Newton Raphson Method 51
3.5 Model Parameters 51
3.6 Calculational Procedure 54
4. Results and Discussion 56
4.1 Simulation result 56
4.2 Percentage of Excitons Transferring to Polarons 59
4.3 The Stretched Exponential Factor β 62
4.4 The Band Banding of TiO2 63
5. Conclusion 65
5.1 The Role of Surface Modifier In P3HT/surface modified-TiO2 Solar Cells 65
5.2 How to Select Suitable Surface Modifier 66

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