硅纳米线阵列的可控制备及新型异质结太阳电池研究

发布时间：2018-08-04 15:26

【摘要】：太阳能是一种取之不尽、用之不竭的可再生清洁能源，有望成为21世纪主要的替代能源之一。光伏电池是将太阳能直接转换为电能的核心器件。在目前的商业应用中，最为常见的光伏电池包括单晶硅太阳电池与多晶硅太阳电池。但是，较高的发电成本、理论转换效率的限制与弯折易破碎等问题阻碍了晶硅太阳电池的广泛应用。硅纳米线阵列由于具有独特的光学、光电、机械柔性等性质被引入硅太阳电池的研究，为新一代硅太阳电池的低成本制作、转化效率的提升及柔性功能的开发提供了新思路。基于此，本课题采用湿化学刻蚀方法，在单晶硅表面制备出均匀的硅纳米线阵列，探索硅纳米线的锥化机制及形成机理，调控硅纳米线的尺寸、表面质量与形貌，提升减反射与光吸收性能。在此基础上，设计制备硅纳米线/PEDOT:PSS异质结太阳电池。开发硅纳米线阵列转移与硅片减薄的新技术，实现器件的柔性特征，其主要研究工作如下：通过臭氧预处理使硅表面钝化，促进银纳米粒子在4英寸硅表面的均匀电镀，获得硅片级均匀的硅纳米线阵列。系统研究了硅纳米线的长度、填充率及表面质量的调控方法。利用银纳米粒子在催化硅刻蚀中的连续溶解特征，制备出锥形的硅纳米线阵列。提出自析出的K2SiF6晶体作为掩蔽进行硅刻蚀，获得硅微米柱/纳米线复合阵列。研究了单分散的贵金属纳米粒子、薄膜及具有纳米孔薄膜的催化刻蚀特征，指出具有纳米孔特征的贵金属薄膜可促进硅纳米线阵列的形成。利用电子显微镜和电子自旋共振光谱仪探测了银粒子在催化刻蚀硅中的形态变化，揭示了硅纳米线的锥化机制。系统研究了单一型与混合型氧化剂的种类、浓度对硅纳米线形貌的影响，阐明了硅纳米线、多孔硅纳米线、硅微米柱/纳米线复合阵列及抛光硅的形成机理。研究了银纳米粒子在硅材料中的运动方向，指出乙醇试剂可以诱导硅纳米线的生成取向。系统研究了硅纳米线的长度、填充率、掺杂类型及浓度对其减反射性能的影响。建立了多孔锥形硅纳米线的有效折射率模型，理论计算与实验测试表明多孔锥形硅纳米线在300-1700nm波段呈现出宽光谱减反射性能，，贵金属纳米粒子修饰能够进一步抑制在近红外波段的反射损失。硅纳米线阵列薄膜在550nm波段的光吸收率接近95%，硅纳米线的多孔化进一步提升长波段光吸收。将PEDOT:PSS有机材料引入硅纳米线阵列中，溶液法制备出硅纳米线/PEDOT:PSS异质结太阳电池。研究了上电极、PEDOT:PSS薄膜的厚度及掺杂、硅纳米线的结构参数对该电池光伏性能的影响。综合优化工艺技术后，电池效率提升至9.7%，并进一步研究了相对湿度对该电池稳定性的影响。研究了硅微纳结构薄膜的关键制作工艺。一方面，采用化学刻蚀与电场辅助刻蚀的方法，诱导银纳米粒子的横向刻蚀，在硅纳米线阵列与硅基底之间生成裂痕，提升硅纳米阵列的转移质量。另一方面，利用自主研发的贵金属纳米粒子催化硅减薄技术，获得表面粗糙度为13nm、厚度低于30μm的超薄硅片，并在超薄硅片上构筑微纳结构达到光吸收增强的目的。在此基础上，搭建硅纳米线/PEDOT:PSS异质结柔性太阳电池的原型器件。
[Abstract]:Solar energy is an inexhaustible and inexhaustible renewable clean energy, which is expected to become one of the main alternative energy sources in the twenty-first Century. Photovoltaic cells are the core components of the direct conversion of solar energy into electrical energy. In the current commercial applications, the most common photovoltaic cells include single crystal silicon solar cells and polysilicon solar cells. The high cost of power generation, the limitation of theoretical conversion efficiency and the breakage of bending and easy breaking have hindered the wide application of crystalline silicon solar cells. The silicon nanowire array has been introduced into the research of silicon solar cells because of its unique optical, photoelectric, mechanical flexibility and other properties. It is the low cost production of the new generation of silicon solar cells, the improvement of the conversion efficiency and the softness of the new generation of silicon solar cells. The development of sexual function provides new ideas. Based on this, we use wet chemical etching method to prepare homogeneous silicon nanowire array on the surface of monocrystalline silicon, explore the coning mechanism and formation mechanism of silicon nanowires, regulate the size of silicon nanowires, surface quality and morphology, lift and reduce reflection and light absorption properties. On this basis, the design system is designed. The silicon nanowire /PEDOT:PSS heterojunction solar cell is used to develop the new technology of silicon nanowire array transfer and silicon wafer thinning to realize the flexible feature of the device. The main research work is as follows:
By ozone pretreatment, the silicon surface is passivated to promote the uniform electroplating of silver nanoparticles on the 4 inch silicon surface, and the silicon nanowire array is obtained. The length, filling rate and surface quality of the silicon nanowires are systematically studied. The cones are prepared by the continuous dissolution characteristics of silver nanoparticles in the etching of the catalytic silicon. A silicon nanowire array is proposed. A self etching K2SiF6 crystal is used as a mask to conduct silicon etching, and a silicon microcolumn / nanowire composite array is obtained.
The catalytic etching characteristics of monodisperse noble metal nanoparticles, thin films and nanoscale thin films are studied. It is pointed out that the noble metal films with nanoscale characteristics can promote the formation of silicon nanowire arrays. The morphological changes of silver particles in the catalytic etching of silicon are detected by electron microscope and electron spin resonance spectrometer. The mechanism of the coning of rice line. The effects of the type and concentration of single and mixed oxidants on the morphology of silicon nanowires were studied. The formation mechanism of silicon nanowires, porous silicon nanowires, silicon micron column / nanowire composite arrays and polished silicon were clarified. The direction of the movement of silver nanoparticles in silicon materials was studied. The generation orientation of silicon guided nanowires.
The effect of the length, filling rate, type and concentration of silicon nanowires on its antireflection properties was studied. The effective refractive index model of the porous tapered silicon nanowires was established. The theoretical calculation and experimental test showed that the porous tapered silicon nanowires showed a broad spectral reflectance in the 300-1700nm band, and the modified energy of the noble metal nanoparticles. The reflection loss in the near infrared band is further suppressed. The optical absorption rate of the silicon nanowire array film in the 550nm band is close to 95%, and the porous silicon nanowires can further enhance the optical absorption of the long band.
The PEDOT:PSS organic material was introduced into the silicon nanowire array and the silicon nanowire /PEDOT:PSS heterojunction solar cell was prepared by solution method. The thickness and doping of the upper electrode, the PEDOT:PSS film and the structure parameters of the silicon nanowire on the photovoltaic performance of the cell were studied. The efficiency of the battery was increased to 9.7% after a comprehensive optimization technique and further research was carried out. The effect of relative humidity on the stability of the battery was investigated.
On the one hand, the chemical etching and electric field assisted etching are used to induce the transverse etching of the silver nanoparticles, to create a fissure between the silicon nanowire array and the silicon substrate, and to improve the transfer quality of the silicon nanowire arrays. The other side, using the self developed noble metal nanoparticles, is used as a catalyst. Silicon thinning technique is used to obtain ultra thin silicon with a surface roughness of 13nm and a thickness of less than 30 u m, and to build a micro nano structure on ultra thin silicon to achieve light absorption enhancement. On this basis, a prototype device for the /PEDOT:PSS heterojunction flexible solar cell of silicon nanowires is built.
【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TB383.1;TM914.4

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