量子点敏化太阳能电池光阳极膜结构优化研究
发布时间：2018-08-22 07:17
【摘要】：QDSSC由于其成本低、理论转换效率高被认为是一种经济、高效的第三代太阳能电池，从而受到研究者的广泛关注。光阳极材料是QDSSC中的重要部分，起着光生电荷分离和传输的作用。因此，光阳极材料的结构对QDSSC的光电性能有着决定性作用。理想的光阳极材料应具有1)高比表面积，为量子点的沉积提供更多成核位点提高量子点负载比例；2)有序的组装结构，形成高效传输通道有利于光生电子的快速传输；3)良好的光散射能力，最大限度的拓宽吸收范围并捕获入射太阳光。本文利用不同方法制备出多种TiO2和SnO2结构作为光阳极材料，将其应用于CdS/CdSe共敏化量子点太阳能电池，并研究其微/纳米结构对其光电转换效率的影响机制。主要的研究内容如下： （1）用十六烷基三甲基溴化铵(CTAB)辅助溶剂热方法制得了独特的石墨烯/TiO2复合结构。研究发现CTAB能够促使TiO2纳米晶在还原石墨烯上均匀分布和高密度包覆，并将复合材料用作光阳极。由于TiO2纳米晶高密度包覆的石墨烯(RGT-H)具有高量子点负载量、光散射能力，可以有效地捕获入射光，同时具有低载流子复合几率和阶跃能级，能够有效抑制注入电子的反向扩散，从而RGT-H电池的光电流密度达到12.38mAcm-2，开路电压569mV,填充因子57%，故此获得了4.02%的光电转换效率，与纳米晶体电池(2.85%)相比提高~40%。 （2）通过溶剂热法制备出多维TiO2分级结构(MD-THSs)，它是由零维的纳米晶先经过有序排列，形成一维介孔纳米带，进而组装形成三维分级结构。将其作为光电阳极用于CdS/CdSe共敏化量子点太阳能电池，通过对光阳极膜厚度优化，厚度为~15μm的光阳极可达到14.39mAcm-2的电流密度，561mV的开路电压，从而达到4.20%的光电转换效率，与纳米晶电池相比，光电转换效率高出~35%。这主要是由于MD-THSs具有高比表面积(160m2g-1)，宽孔径分布(1~100nm)以及定向有序的初级TiO2纳米晶，从而有利于量子点的负载，电解液在阳极膜中的扩散以及光电子的传输。 （3）利用水热法制备出SnO2材料并研究其生长过程及调控机理。同时，实验证实pH值可以有效的调控纳米颗粒的组装过程，通过调节NaOH添加量，可选择性生成棒状结构，微球以及纳米颗粒。利用这些不同的SnO2结构，经TiCl4处理制备TiO2/SnO2复合光阳极结构用于QDSSC。试验表明，，纳米微球可以有效地平衡比表面积和阳极膜中晶界数量，在提高量子点负载量的同时保证了光电子的有效传输。故此相应的QDSSC达到1.61%的转换效率，与棒状结构和纳米颗粒结构光阳极相比分别高~65%和~46%。
[Abstract]:Because of its low cost and high theoretical conversion efficiency, QDSSC is considered to be an economical and efficient third generation solar cell, which has been widely concerned by researchers. Photoanode is an important part of QDSSC, which plays the role of photogenic charge separation and transmission. Therefore, the structure of photoanode plays a decisive role in the optoelectronic properties of QDSSC. The ideal photoanode material should have 1) high specific surface area, which can provide more nucleation sites for quantum dot deposition and increase the loading ratio of quantum dots. The formation of an efficient transmission channel is conducive to the rapid transfer of photogenerated electrons. 3) good light scattering ability to maximize the absorption range and capture the incident sunlight. In this paper, a variety of TiO2 and SnO2 structures were prepared as photoanode materials by different methods, and were applied to CdS/CdSe co-sensitized quantum dot solar cells. The mechanism of the effect of microstructures and nanostructures on the photoelectric conversion efficiency was investigated. The main contents are as follows: (1) the unique graphene / TIO _ 2 composite structure was prepared by (CTAB) assisted solvothermal method with cetyltrimethylammonium bromide. It is found that CTAB can promote the uniform distribution and high density coating of TiO2 nanocrystals on reduced graphene and use the composites as photoanode. Because the graphene (RGT-H) coated with high density of TiO2 nanocrystals has high quantum dot loading and light scattering ability, it can effectively capture incident light, and has low carrier recombination probability and step energy level, which can effectively suppress the reverse diffusion of injected electrons. The photocurrent density of RGT-H cell is 12.38 mAcm-2, the open circuit voltage is 569 MV, the filling factor is 57, and the photoelectric conversion efficiency of 4.02% is obtained. Compared with nanocrystalline battery (2.85%), the multi-dimensional TiO2 fractionation structure (MD-THSs) was prepared by solvothermal method, which was arranged in an ordered order by zero-dimensional nanocrystalline to form one-dimensional mesoporous nanoribbons, and then assembled to form three-dimensional classification structure. The photoanode is used as a photoanode for CdS/CdSe co-sensitized quantum dot solar cells. By optimizing the thickness of photoanode film, the photoanode with thickness of 15 渭 m can reach the open circuit voltage of 561mV of current density of 14.39mAcm-2, thus the photoelectric conversion efficiency of 4.20% can be achieved. Compared with nanocrystalline battery, the photoelectric conversion efficiency is higher than that of nanocrystalline battery. This is mainly due to the fact that MD-THSs has high specific surface area (160m2g-1), wide pore size distribution (1~100nm) and oriented primary TiO2 nanocrystals, which is beneficial to the loading of quantum dots. Diffusion of electrolyte in anodic film and photoelectron transport. (3) SnO2 material was prepared by hydrothermal method and its growth process and regulation mechanism were studied. At the same time, it is proved that pH value can effectively regulate the assembly process of nanoparticles. By adjusting the amount of NaOH, the rod-like structure, microspheres and nanoparticles can be selectively formed. Using these different SnO2 structures, TiO2/SnO2 composite photoanode structures were prepared by TiCl4 treatment for QDS SCS. The experimental results show that the nanocrystalline microspheres can effectively balance the specific surface area and the number of grain boundaries in the anodic film, and ensure the effective transmission of photoelectrons while increasing the quantum dot loading. Therefore, the conversion efficiency of the corresponding QDSSC is 1.6 1%, which is 65% and 46% higher than that of the rod structure and nanocrystalline structure photoanode, respectively.
【学位授予单位】：河南师范大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM914.4;O611.2
[Abstract]:Because of its low cost and high theoretical conversion efficiency, QDSSC is considered to be an economical and efficient third generation solar cell, which has been widely concerned by researchers. Photoanode is an important part of QDSSC, which plays the role of photogenic charge separation and transmission. Therefore, the structure of photoanode plays a decisive role in the optoelectronic properties of QDSSC. The ideal photoanode material should have 1) high specific surface area, which can provide more nucleation sites for quantum dot deposition and increase the loading ratio of quantum dots. The formation of an efficient transmission channel is conducive to the rapid transfer of photogenerated electrons. 3) good light scattering ability to maximize the absorption range and capture the incident sunlight. In this paper, a variety of TiO2 and SnO2 structures were prepared as photoanode materials by different methods, and were applied to CdS/CdSe co-sensitized quantum dot solar cells. The mechanism of the effect of microstructures and nanostructures on the photoelectric conversion efficiency was investigated. The main contents are as follows: (1) the unique graphene / TIO _ 2 composite structure was prepared by (CTAB) assisted solvothermal method with cetyltrimethylammonium bromide. It is found that CTAB can promote the uniform distribution and high density coating of TiO2 nanocrystals on reduced graphene and use the composites as photoanode. Because the graphene (RGT-H) coated with high density of TiO2 nanocrystals has high quantum dot loading and light scattering ability, it can effectively capture incident light, and has low carrier recombination probability and step energy level, which can effectively suppress the reverse diffusion of injected electrons. The photocurrent density of RGT-H cell is 12.38 mAcm-2, the open circuit voltage is 569 MV, the filling factor is 57, and the photoelectric conversion efficiency of 4.02% is obtained. Compared with nanocrystalline battery (2.85%), the multi-dimensional TiO2 fractionation structure (MD-THSs) was prepared by solvothermal method, which was arranged in an ordered order by zero-dimensional nanocrystalline to form one-dimensional mesoporous nanoribbons, and then assembled to form three-dimensional classification structure. The photoanode is used as a photoanode for CdS/CdSe co-sensitized quantum dot solar cells. By optimizing the thickness of photoanode film, the photoanode with thickness of 15 渭 m can reach the open circuit voltage of 561mV of current density of 14.39mAcm-2, thus the photoelectric conversion efficiency of 4.20% can be achieved. Compared with nanocrystalline battery, the photoelectric conversion efficiency is higher than that of nanocrystalline battery. This is mainly due to the fact that MD-THSs has high specific surface area (160m2g-1), wide pore size distribution (1~100nm) and oriented primary TiO2 nanocrystals, which is beneficial to the loading of quantum dots. Diffusion of electrolyte in anodic film and photoelectron transport. (3) SnO2 material was prepared by hydrothermal method and its growth process and regulation mechanism were studied. At the same time, it is proved that pH value can effectively regulate the assembly process of nanoparticles. By adjusting the amount of NaOH, the rod-like structure, microspheres and nanoparticles can be selectively formed. Using these different SnO2 structures, TiO2/SnO2 composite photoanode structures were prepared by TiCl4 treatment for QDS SCS. The experimental results show that the nanocrystalline microspheres can effectively balance the specific surface area and the number of grain boundaries in the anodic film, and ensure the effective transmission of photoelectrons while increasing the quantum dot loading. Therefore, the conversion efficiency of the corresponding QDSSC is 1.6 1%, which is 65% and 46% higher than that of the rod structure and nanocrystalline structure photoanode, respectively.
【学位授予单位】：河南师范大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM914.4;O611.2
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