XJIPC OpenIR  > 材料物理与化学研究室
Thesis Advisor徐金宝
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Name硕士
Degree Discipline材料物理与化学
Keyword有机—无机杂化钙钛矿 光电性质 无铅钙钛矿太阳能电池 稳定性

钙钛矿太阳能电池作为一种新型薄膜太阳能电池,具有制备工艺简单、生产成本低廉以及光电转换效率高等优点。目前,钙钛矿太阳能电池的最高效率已经超过20%,成为最有前景的第三代薄膜太阳能电池。但是,作为一种新材料,仍有许多亟待解决的问题,例如对有机无机杂化钙钛矿材料的基本物理性能研究尚不充分,热稳定性差以及含有环境有害元素铅等问题。针对这些问题,我们主要从以下几方面展开研究:(1)通过旋涂工艺,以CH3NH3PbI3为光吸收料,制备了钙钛矿太阳能电池,研究了其在可见光辐照下的I-V特性曲线,得到开路电压Voc为0.69V,短路电流密度Jsc为 21 mA·cm-2,填充因子FF为0.44,光电器件的转化效率Pmax为6.4%。并利用光学椭偏仪对CH3NH3PbI3薄膜在30~100℃范围内进行原位测试。实验结果表明在30~100℃范围内,CH3NH3PbI3薄膜具有较好的光吸收性质以及较大的介电常数,在70℃的时候发生相变。(2)在FTO衬底上制备了CH3NH3PbI3-xBrx薄膜,研究Br离子其晶体结构和光电性质的影响。在常温下,CH3NH3PbI3-xBrx薄膜属于四方相结构,相对于高温下的立方相,具有较低的对称性。随着Br离子含量的增加,CH3NH3PbI3-xBrx薄膜的光吸收截止边发生蓝移,带隙逐渐变大(从1.55eV,逐渐变大到1.86eV),晶格常数变小,同时介电常数虚部谱也发生蓝移,电子跃迁所需能量也相应增加。(3)制备出(CH3NH3)3Bi2I9薄膜,其光吸收截止边在572nm,带隙为2.2eV,功函数为532.56mV。通过旋涂工艺制备出了(CH3NH3)3Bi2I9钙钛矿太阳能电池,测试其光伏特性曲线,其开路电压为0.42V,短路电流密度为1.48mA·cm-2,填充因子为0.25,最大光电转换效率为0.16%。(4)利用热重差分仪研究(CH3NH3)3Bi2I9材料的热稳定性,(CH3NH3)3Bi2I9薄膜在145℃的时候发生相变,在254℃的时候开始分解,分解成CH3NH3I和BiI3,和CH3NH3PbI3材料相比较,具有较好的热稳定性。同时研究了退火温度对(CH3NH3)3Bi2I9薄膜的结构、形貌和光学性质的影响,实验发现在100~225℃温度范围内退火(CH3NH3)3Bi2I9薄膜结构保持稳定,随着退火温度的升高,表面形貌从棒状结构变成多边形,薄膜致密性也得到提高,在175℃退火下,表面形貌呈完整的多边形,且致密性最好,粗糙度最低。

Other Abstract

As a new generation of films solar cell, perovskite solar cell has some advantages such as easy manufacturing process, low cost and high photoelectric conversion efficiencies. Up to now, perovskite solar cells has arrived over 20% of photoelectric conversion efficiencies and become the most promising candidate for the third generation solar cells. While, as a new material, there are plenty of research works need to investigate on hybrid perovskite material. For example, the study of basic physical properties, improvement ofthermos stability and design of led-free hybrid perovskite material. This dissertation aims at the problems above, and carry out the research work from the following several directions:(1) CH3NH3PbI3 perovskite solar cell has been established through spin coating. The I-V curve shows that the short-circuit current (Jsc) is 21mA·cm-2, open-circuit voltage (Voc) is 0.69V and fill factoris 0.44, the device’s photon to current efficiency (Pmax) is 6.4%. Also, the optical and electrical properties were studied by SE under the temperatures from 30℃ to 100℃, respectively. The results insisted that the CH3NH3PbI3 film keep big complex refractive index and complex dielectric constant. The CH3NH3PbI3 film has a phase transition at the temperature of 70℃.(2) CH3NH3PbI3-xBrx thin films on FTO substrate were synthesized successfully. The crystal structure and optical properties of these films changed with different ratios of I-/Br-ions. The lattice parameters were reduced and the optical absorption edges were blue-shifted with the increasing ratio of Br- ions. The dielectric spectra have revealed that tetragonal CH3NH3PbI3-xBrx thin films at room temperature not only have a lower symmetry than cubic films, but also provide more electron transition energies. The mechanism is discussed correspondingly.(3)The (CH3NH3)3Bi2I9 film were designed and synthesized. Its optical absorption edges is 572nm, energy band is 2.2eV and the work function is 532.56mV. The (CH3NH3)3Bi2I9 solar cell was also established, with the short-circuit current (Jsc) of 1.48mA·cm-2, open-circuit voltage (Voc) of 0.42V and fill factorof 0.25, the device’s photon to current efficiency of 0.16%. (4) The thermos-stability of (CH3NH3)3Bi2I9 powder was studied. The phase transition of (CH3NH3)3Bi2I9 powder was found at 145℃. At 254℃,(CH3NH3)3Bi2I9 powder began to decompose into CH3NH3I and BiI3. Compared with CH3NH3PbI3, (CH3NH3)3Bi2I9 show a better thermo-stability. Then the effect of temperature on the (CH3NH3)3Bi2I9 film was studied. Under the temperature range of 100~225℃,it kept the same phase, while the crystallinity is changing better with the increase of temperature. However, with the temperature increasing, the “stick”-type particles gradually shrink and then are completely replaced by polyhedra–shaped particles with a relatively smooth surface. At the temperature of 175℃, it has the best morphology.

Document Type学位论文
Recommended Citation
GB/T 7714
王贺勇. 有机金属卤化物钙钛矿太阳能电池制备工艺及光电性能研究[D]. 北京. 中国科学院大学,2016.
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