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毕业设计(论文)

PbS量子点的制备及其光电性能研究

学 院 专 业 班级学号 学生姓名 指导教师

资源与材料学院 材料科学与工程

8080228 张雨琳 王晓强

2012年6月10日

东北大学秦皇岛分校毕业设计(论文) 第 I 页

PbS量子点的制备及其光电性能研究

摘 要

本论文采用有机合成法,选择氧化铅和三甲基硅硫作为前驱体,制备了缺陷少、结晶性好,尺寸分布均匀的PbS量子点。在此基础上,分别用X 射线衍射仪、扫描电镜、紫外-可见漫反射光谱仪对所制备的近红外PbS量子点进行表征。结果表明,合成的量子点尺寸均匀,其吸收光的波段在700-1000 nm。

在制备出PbS量子点的基础上,通过具有功能基团的有机分子将制备的PbS量子点连接到TiO2纳晶薄膜上,并以此为光电极组装成PbS量子点敏化纳晶薄膜太阳能电池;并对组装的太阳能电池的光电转换性能进行了测试和分析;测得其光电转化效率为0.015%,分析其转化效率低的原因及改进方案。

另外,为了提高PbS敏化电池的效率,本文对提高TiO2薄膜基体的性能进行了进一步探索。分别测试了介孔性、涂膜面积、导电玻璃等制备工艺对TiO2纳晶薄膜的影响,最终所组装电池最高光电转化效率为6.69%。

关键词: PbS量子点,纳晶薄膜太阳能电池,量子点敏化,光电转换效率

东北大学秦皇岛分校毕业设计(论文) 第 II 页 Synthesis and Photoelectric Properties of PbS Quantum Dots

Author: Y. L. Zhang Tutor: X. Q. Wang

Abstract

In this thesis, PbS quantum dots (QDs) with mean particle size and fewer defects, good crystallization were synthesized in organometallic synthetic method. The XRD, SEM and UV-Vis diffuse reflectance spectroscopy characterization show that the monodisperse PbS QDs have uniform size and estimated about 30% quantum yield. The concentration of reaction reagents are affected on the size and optical property of PbS QDs. The results show that the size of quantum dot is uniform and the wavelength of absorbed light is from 700 to 1000nm.

PbS QDs were connected to the nanocrystalline TiO2 Porous thin film with the organic molecules functional groups to form Photoelectrodes which is used to assemble the PbS QDs sensitized solar cell. Furthermore, the light to electricity conversion efficiency of PbS QDs sensitized solar cell was tested and analyzed. The standard efficiency of the light to electricity conversion is 0.015%. In addition, we researched the reasons of the low conversion efficiency and analyzed how to improve its capability.

In addition, we also studied how to improve the properties of the TiO2 thin film in the specific surface area, the conductive substrate and the thickness. Eventually, the highest photoelectric conversion is 6.69%.

Key Words: PbS dot, nanocrystalline thin film solar cell, quantum dot sensitization,

light to electricity conversion efficiency

东北大学秦皇岛分校毕业设计(论文) 第 III 页

目 录

1 绪 论 .................................................................................................................................... 1

1.1 太阳能电池的发展 ..................................................................................................... 1 1.2 染料敏化太阳能电池 ................................................................................................. 2

1.2.1 染料敏化太阳能电池工作原理 ........................................................................ 3 1.2.2 染料敏化剂的种类 ............................................................................................ 3 1.2.3 量子点敏化太阳能电池 .................................................................................... 4 1.3 PbS量子点研究现状 ................................................................................................. 6

1.3.1 PbS量子点与光伏电池 .................................................................................... 6 1.3.2 PbS量子点的制备现状 .................................................................................... 7 1.4 本课题的研究意义与工作设想 ................................................................................. 8 2 PbS量子点的制备和表征................................................................................................. 10

2.1 实验条件 ................................................................................................................... 10 2.2 PbS量子点的制备 ................................................................................................... 11

2.2.1 实验步骤 .......................................................................................................... 11 2.2.2 实验注意事项 .................................................................................................. 12 2.3 PbS量子点的结构表征结果与讨论 ....................................................................... 13

2.3.1 PbS量子点的相结构表征 .............................................................................. 13 2.3.2 PbS量子点的粒径与形貌的结果分析 .......................................................... 14 2.4 PbS量子点的漫反射谱分析 ................................................................................... 16

2.4.1 漫反射光谱(DRS)测试原理 ...................................................................... 16 2.4.2 PbS在紫外区的漫反射光谱分析 .................................................................. 17 2.4.3 PbS在近红外区的漫反射光谱分析 .............................................................. 18 2.5 PbS量子点的傅里叶变换红外光谱分析 ............................................................... 18 2.6 磁控溅射制备PbS/TiO2薄膜 .................................................................................. 19

2.6.1 磁控溅射原理简介 .......................................................................................... 20 2.6.2 实验用磁控溅射镀膜装置介绍 ...................................................................... 21

东北大学秦皇岛分校毕业设计(论文) 第 IV 页 2.6.3 磁控溅射制备PbS薄膜 ................................................................................. 24 2.7 本章小结 ................................................................................................................... 25 3 PbS量子点光伏器件的组装与性能测试 ........................................................................ 27

3.1 实验条件 ................................................................................................................... 27 3.2 实验步骤及流程 ....................................................................................................... 28 3.3 光电化学特性测试结果 ........................................................................................... 30 3.4 光电化学特性测试结果分析 ................................................................................... 32 3.5 本章小结 ................................................................................................................... 34 4 TiO2纳晶基体的研究改性 ................................................................................................ 35

4.1 引言 ........................................................................................................................... 35 4.2 实验影响条件的确定 ............................................................................................... 35 4.3 介孔性对光阳极的影响 ........................................................................................... 36

4.3.1 实验方案 .......................................................................................................... 36 4.3.2 I-V测试结果及其分析 ................................................................................... 37 4.4 涂膜面积对光阳极的影响 ....................................................................................... 39

4.4.1 实验方案 .......................................................................................................... 39 4.4.2 I-V测试结果及其分析 ................................................................................... 40 4.5 导电玻璃基底对光阳极的影响 ............................................................................... 41

4.5.1 实验方案 .......................................................................................................... 42 4.5.2 I-V测试结果及其分析 ................................................................................... 43 4.6 本章小结 ................................................................................................................... 44 结论与展望 .............................................................................................................................. 45 致 谢 .................................................................................................................................. 46 参考文献 .................................................................................................................................. 47 附 录 .................................................................................................................................. 51

附录A ................................................................................................................................ 51 附录B ................................................................................................................................ 66