论文总字数：26655字

摘 要

Abstract II

第一章 绪论 1

1.1 研究背景及意义 1

1.1.1 BiFeO₃单相多铁材料 1

1.1.2 BiFeO₃晶体结构 2

1.1.3 BiFeO₃材料基本性质 2

1.2 国内外研究现状 3

1.2.1 铁电材料的光伏效应 3

1.2.2 BiFeO₃材料的光伏效应研究现状 4

1.2.3 挠曲电效应 5

1.2.4 多铁材料的制备方法 5

1.3 本文的研究内容 8

第二章 实验部分 10

2.1 实验方案 10

2.2 实验步骤 11

2.3 实验材料试剂及设备 11

2.4 结构表征与性能测试 12

2.4.1物相与微观形貌 12

2.4.2性能测试 14

第三章 静电纺丝法制备铁酸铋纤维及其性能研究 17

3.1 铁酸铋电纺溶胶的制备 17

3.2 静电纺丝工艺 18

3.3 静电纺丝铁酸铋纤维的烧结 19

3.4 结果与分析 20

3.4.1热重分析（TG-DSC） 20

3.4.2不同烧结温度下的XRD对比 21

3.4.3微观形貌分析 22

3.4.4铁电性分析 23

3.5 本章小结 24

第四章 Cr掺杂BFO纤维带隙调控研究 25

4.1 掺Cr铁酸铋电纺溶胶的制备 25

4.2 静电纺丝过程及烧结处理 26

4.3 静电纺丝掺杂铁酸铋纤维的烧结 26

4.4 结果与分析 26

4.4.1不同烧结温度下的XRD对比 26

4.4.2紫外-可见漫反射光谱 27

4.5 本章小结 29

第五章 结论与展望 30

5.1 实验总结 30

5.2 未来展望 30

致 谢 31

参考文献 32

摘 要

近年来，能源危机越来越严峻，资源丰富、绿色环保的太阳能电池为缓解能源问题提供了新的解决方法。铁酸铋（BiFeO₃）作为一种光活性材料，因其具有大的铁电剩余极化、较半导体带隙较小等特点，在太阳能电池领域引起人们的广泛关注。但是，由于BiFeO₃存在难以极化和对可见光吸收波长范围较窄等缺陷，使其应用受到了限制。因此，使BiFeO₃纤维自发极化，降低其带隙，对于其实际应用于太阳能电池具有重要意义。

本文通过溶胶-凝胶与静电纺丝技术相结合的方法制备具有挠曲度的BiFeO₃纤维，从而引入挠曲电电场使其发生自极化，并通过掺杂Cr降低其带隙。实验结果表明，当烧结温度为570℃时，制得纯相的BiFeO₃；经SEM观察纤维交叉排列，具有一定的挠曲度；进一步，通过PFM测试观察到同一根纤维产生不同极化方向的畴，说明纤维有自极化的现象。对于Cr掺杂的样品，由紫外-可见漫反射光谱分析可知，当Cr掺杂量为10%，烧结温度为570℃，制得纤维的带隙可由2.17eV降到2.04eV。

溶胶-凝胶与静电纺丝技术相结合制得自极化BiFeO₃纤维，同时通过掺杂Cr降低了带隙，这种Cr掺杂BiFeO₃纤维对于太阳能电池具有一定的应用价值。

关键词：静电纺丝，BiFeO₃，自极化纤维，带隙

Abstract

In recent years, the energy crisis has become more and more severe, and resource-rich, green and environmentally-friendly solar cells have provided new solutions to alleviate energy problems. As a photoactive material, bismuth ferric (BiFeO₃) has attracted much attention in the field of solar cells because of its large ferroelectric remanent polarization and smaller semiconductor band gap. However, BiFeO₃ has limitations due to its difficulty in polarization and narrow wavelength range of visible light absorption. Therefore, the BiFeO₃ fiber is spontaneously polarized and its band gap is lowered, which is of great significance for its practical application in solar cells.

In this paper, the BiFeO₃ fiber with deflection is prepared by the combination of sol-gel and electrospinning technology, which introduces a flexural electric field to cause self-polarization and reduces the band gap by doping Cr. The experimental results show that when the sintering temperature is 570 °C, pure phase BiFeO₃ is obtained; the fiber cross-aligned by SEM observation has a certain degree of deflection; the same fiber is observed by PFM test to generate domains with different polarization directions. , indicating that the fiber has a phenomenon of self-polarization. For Cr-doped samples, it can be seen from the UV-visible diffuse reflectance spectroscopy that when the Cr doping amount is 10% and the sintering temperature is 570 ° C, the band gap of the obtained fiber can be reduced from 2.17 eV to 2.04 eV.

The self-polarized BiFeO₃ fiber is prepared by the combination of sol-gel and electrospinning technology, and the band gap is reduced by doping Cr. The Cr-doped BiFeO₃ fiber has certain application value for solar cells.

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