【摘要】：QDSSC由于其成本低、理論轉(zhuǎn)換效率高被認為是一種經(jīng)濟、高效的第三代太陽能電池，從而受到研究者的廣泛關注。光陽極材料是QDSSC中的重要部分，起著光生電荷分離和傳輸?shù)淖饔�。因此，光陽極材料的結(jié)構(gòu)對QDSSC的光電性能有著決定性作用。理想的光陽極材料應具有1)高比表面積，為量子點的沉積提供更多成核位點提高量子點負載比例；2)有序的組裝結(jié)構(gòu)，形成高效傳輸通道有利于光生電子的快速傳輸；3)良好的光散射能力，最大限度的拓寬吸收范圍并捕獲入射太陽光。本文利用不同方法制備出多種TiO2和SnO2結(jié)構(gòu)作為光陽極材料，將其應用于CdS/CdSe共敏化量子點太陽能電池，并研究其微/納米結(jié)構(gòu)對其光電轉(zhuǎn)換效率的影響機制。主要的研究內(nèi)容如下： （1）用十六烷基三甲基溴化銨(CTAB)輔助溶劑熱方法制得了獨特的石墨烯/TiO2復合結(jié)構(gòu)。研究發(fā)現(xiàn)CTAB能夠促使TiO2納米晶在還原石墨烯上均勻分布和高密度包覆，并將復合材料用作光陽極。由于TiO2納米晶高密度包覆的石墨烯(RGT-H)具有高量子點負載量、光散射能力，可以有效地捕獲入射光，同時具有低載流子復合幾率和階躍能級，能夠有效抑制注入電子的反向擴散，從而RGT-H電池的光電流密度達到12.38mAcm-2，開路電壓569mV,填充因子57%，故此獲得了4.02%的光電轉(zhuǎn)換效率，與納米晶體電池(2.85%)相比提高~40%。 （2）通過溶劑熱法制備出多維TiO2分級結(jié)構(gòu)(MD-THSs)，它是由零維的納米晶先經(jīng)過有序排列，形成一維介孔納米帶，進而組裝形成三維分級結(jié)構(gòu)。將其作為光電陽極用于CdS/CdSe共敏化量子點太陽能電池，通過對光陽極膜厚度優(yōu)化，厚度為~15μm的光陽極可達到14.39mAcm-2的電流密度，561mV的開路電壓，從而達到4.20%的光電轉(zhuǎn)換效率，與納米晶電池相比，光電轉(zhuǎn)換效率高出~35%。這主要是由于MD-THSs具有高比表面積(160m2g-1)，寬孔徑分布(1~100nm)以及定向有序的初級TiO2納米晶，從而有利于量子點的負載，電解液在陽極膜中的擴散以及光電子的傳輸。 （3）利用水熱法制備出SnO2材料并研究其生長過程及調(diào)控機理。同時，實驗證實pH值可以有效的調(diào)控納米顆粒的組裝過程，通過調(diào)節(jié)NaOH添加量，可選擇性生成棒狀結(jié)構(gòu)，微球以及納米顆粒。利用這些不同的SnO2結(jié)構(gòu)，經(jīng)TiCl4處理制備TiO2/SnO2復合光陽極結(jié)構(gòu)用于QDSSC。試驗表明，，納米微球可以有效地平衡比表面積和陽極膜中晶界數(shù)量，在提高量子點負載量的同時保證了光電子的有效傳輸。故此相應的QDSSC達到1.61%的轉(zhuǎn)換效率，與棒狀結(jié)構(gòu)和納米顆粒結(jié)構(gòu)光陽極相比分別高~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.
【學位授予單位】：河南師范大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TM914.4;O611.2

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