有机—无机杂化太阳能电池中的界面问题研究

发布时间：2018-01-28 06:41

  本文关键词： 有机-无机 杂化电池 界面 接触 钝化　出处：《华北电力大学(北京)》2016年硕士论文　论文类型：学位论文

【摘要】：随着全球化石能源的不断减少和环境问题的日益严重,太阳能作为一种洁净的可再生能源引起了人们越来越多的关注。而太阳能电池能够通过光电效应将太阳光能直接转化成电能,是一种理想的太阳能利用方式。有机-无机杂化太阳能电池作为一种新型的光伏电池,融合了有机材料和无机材料的特点,有望成为一种低价、高效且具备柔性特征的光伏电池。但是,现阶段这种杂化电池的光电转换效率还比较低,界面问题是制约其效率的主要原因之一：硅材料和有机聚合物材料性质的差异致使两相界面接触不佳；晶硅表面往往存在大量的悬挂键而引起载流子的严重复合。这些界面问题将导致光生载流子在有机-无机界面处不能进行有效的分离。因此,研究并改善界面特性对于提高有机-无机杂化电池的性能,促进杂化电池的工业生产和商业应用具有非常重要的意义。基于此,我们首先用氢氧化钾化学刻蚀法制备了超薄的柔性硅片,并分别以525μm厚硅片和1 8μm柔性薄硅片为基底,以共轭导电聚合物PEDOT:PSS为有机空穴传输层,制备了平板型单晶硅/PEDOT:PSS有机-无机杂化异质结电池。然后我们主要从优化单晶硅/PEDOT:PSS的界面接触和实现单晶硅表面的有效钝化两个方面研究了这种杂化电池的界面问题。主要研究工作如下：研究了界面接触对杂化电池器件性能的影响并对其进行优化。通过在PEDOT:PSS溶液中掺入全氟表面活性剂FSH使单晶硅与PEDOT:PSS的界面接触角降低了近60%,极大地改善了PEDOT:PSS溶液在硅表面的浸润性；同时通过调控PEDOT:PSS混合溶液的旋涂转速,得到转速为3000r/min时PEDOT:PSS薄膜在单晶硅表面的成膜质量最佳,杂化电池的性能最佳；此外,利用原子力显微镜扫描减薄前后单晶硅片的表面形貌,我们发现薄硅片的表面均方根(RMS)粗糙度是厚硅片的10倍左右,这使得薄硅片表面与PEDOT:PSS薄膜的接触面积大幅提高,更有利于载流子在界面处分离,界面接触电阻有效降低,因此基于薄硅制备的杂化电池串联电阻更低,填充因子更高,测量的短路电流密度与理论极限电流密度之比更大。对比了自然氧化(NO)钝化、氢氟酸(HF)钝化和本征非晶硅(ia-Si)钝化三种方法对单晶硅表面的钝化效果及其对杂化电池性能的影响。通过少子寿命测试得到不同钝化方法处理的单晶硅表面少子寿命,并计算出对应的少子表面复合速率。复合速率越低说明钝化效果越好,其制备的杂化电池具有更高的短路电流密度。通过调控自然氧化时间或者非晶硅沉积温度得到最佳的自然氧化时间为12h,最佳非晶硅沉积温度为250℃。横向比较而言,本征非晶硅的对硅片的钝化效果最好,其对应的杂化电池的短路电流密度最高,厚硅与薄硅电池的最高效率分别达到9.78%和5.68%；氢氟酸钝化的效果次之,自然氧化钝化的效果最差。这种趋势对于厚硅和薄硅电池是一致的。
[Abstract]:With the decrease of global fossil energy and the increasingly serious environmental problems. As a kind of clean renewable energy, solar energy has attracted more and more attention. Solar cells can convert solar energy directly into electric energy by photoelectric effect. As a new type of photovoltaic cells, organic and inorganic hybrid solar cells are expected to become a low price because of the characteristics of organic and inorganic materials. Highly efficient and flexible photovoltaic cells. However, at present, the photovoltaic conversion efficiency of this hybrid cell is still relatively low. The interface problem is one of the main reasons that restrict its efficiency: the difference of the properties of silicon material and organic polymer material results in poor contact between the two phases; There are often a large number of hanging bonds on the surface of crystalline silicon, which lead to the serious recombination of carriers. These interface problems will lead to the photogenic carriers can not be effectively separated at the organic-inorganic interface. It is very important to study and improve the interface characteristics for improving the performance of organic-inorganic hybrid battery and promoting the industrial production and commercial application of hybrid battery. At first, ultrathin flexible silicon wafers were prepared by chemical etching of potassium hydroxide on 525 渭 m thick silicon wafers and 18 渭 m flexible thin silicon wafers, respectively. The conjugated conductive polymer PEDOT:PSS was used as the organic hole transport layer. The monocrystalline monocrystalline silicon / PEDOT: PSS organic-inorganic hybrid heterojunction battery was prepared, and then we optimized monocrystalline silicon / PEDOT:. The interface problem of the hybrid battery is studied in the aspects of interface contact of PSS and effective passivation of monocrystalline silicon surface. The main research work is as follows:. The effects of interface contact on the performance of hybrid battery devices were studied and optimized. The monocrystalline silicon and PEDOT were prepared by adding perfluorinated surfactant FSH in PEDOT:PSS solution. The interface contact angle of PSS is reduced by nearly 60%. The wettability of PEDOT:PSS solution on silicon surface is greatly improved. At the same time, by adjusting the rotation speed of PEDOT:PSS mixed solution, the film quality of PEDOT:PSS film on the surface of monocrystalline silicon is the best when the rotational speed is 3000r / min. The hybrid battery has the best performance. In addition, the surface morphology of single crystal silicon wafer before and after thinning was observed by atomic force microscope (AFM). We found that the surface RMS roughness of thin silicon wafer is about 10 times that of thick silicon wafer. As a result, the contact area between the thin silicon surface and the PEDOT:PSS film is greatly increased, which is more favorable to the separation of carriers at the interface and the effective reduction of the interface contact resistance. Therefore, the hybrid battery based on thin silicon has lower series resistance, higher filling factor and larger ratio of measured short circuit current density to theoretical limit current density. HFH) passivation and Intrinsic amorphous Silicon I-Si). The passivation effect of three passivation methods on the surface of monocrystalline silicon and its effect on the performance of hybrid battery were studied. The minority carrier lifetime of the surface of monocrystalline silicon treated by different passivation methods was obtained by minority carrier lifetime test. The lower the recombination rate is, the better the passivation effect is. The hybrid battery has higher short-circuit current density and the optimum natural oxidation time is 12 hours by adjusting the natural oxidation time or amorphous silicon deposition temperature. The optimum deposition temperature of amorphous silicon is 250 鈩，

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