小尺寸四针状纳米ZnO的制备及其在太阳能电池的应用

发布时间：2018-02-22 03:40

  本文关键词： DCVD 四针状纳米ZnO 量子点 染料敏化 异质结太阳能电池　出处：《广西大学》2014年硕士论文　论文类型：学位论文

【摘要】：为应对全球化石燃料加速枯竭和全球日益高涨的能源需求,可再生能源将逐步取代常规化石燃料能源。太阳能资源开发中光伏发电存在巨大的潜能。 ZnO是直接跃迁、宽禁带材料(Eg=3.37eV),具有高的激子束缚能(60meV),有压电、导电、在可见光范围内透明、在红外波段高反射率等特性。因而,ZnO应用广泛,可用作LCD或LED的透明电极、光伏器件、化学传感器、铁电存储器、热反射器、表面声波器件和低损耗波导等。 目前太阳能电池从技术上主要分为：硅太阳能电池、碲化镉(CdTe)太阳能电池、铜铟镓硒(CIGS)薄膜电池、Ⅲ-Ⅴ族化合物太阳能电池、有机太阳能电池、染料敏化太阳能电池(DSSC)等。 本论文在以往方法的基础上创造性地发明了一种制备直径在20nm以下的小尺寸四针状纳米ZnO的方法,而且大大提高了小尺寸四针状纳米氧化锌的产率。本论文采用X射线衍射(XRD)、扫描电子显微镜(SEM)、PL表征、紫外可见光谱表征对制得的小尺寸四针状纳米ZnO样品的进行了表征。通过研究不同工艺参数对制备小尺寸四针状纳米ZnO的影响,初步探讨了小尺寸四针状纳米ZnO的形成机理,以此得到了制备小尺寸四针状纳米ZnO优选条件。 本论文接着将制备的小尺寸四针状纳米ZnO分别与CdTe.CdSe.CdS.PbS等量子点制备成ZnO-量子点太阳能电池。又将通过干式化学气相沉积法制备的小尺寸四针状纳米ZnO经过N719染料敏化后组装成了ZnO染料敏化太阳能电池。然后将通过干式化学气相沉积法制备的小尺寸四针状纳米ZnO与对本乙烯撑的衍生物聚[2-甲氧基,5-(2-乙基-己氧基)-对苯乙炔](英文缩写MEH-PPV)组装成了双层结构面异质结无机/有机聚合物太阳能电池。最后采用由500W氙灯作为太阳光模拟器,并由CHI660D型电化学工作站作为电信号输出装置组成的太阳能电池测试系统测试了不同尺寸四针状纳米ZnO制备成的ZnO-CdTe、ZnO-CdSe、ZnO-CdS、ZnO-PbS等ZnO-量子点太阳能电池、染料敏化ZnO太阳能电池、ITO/Au/小尺寸四针状纳米ZnO/MEH-PPV/PEDOT:PSS/ITO太阳能电池。 研究结果表明： (1)锌蒸发温度是影响四针状纳米ZnO形貌和尺寸的关键因素。锌的蒸发温度越高,生成的四针状纳米ZnO的尺寸越大； (2)想要得到高产率的结晶良好的小尺寸四针状纳米ZnO,关键还要控制整个反应体系中不能含有诸如水分子之类会对主要反应2Zn(g)+O2=2ZnO(g)或对四针状纳米ZnO晶体形貌产生影响的物质； (3)干式化学气相沉积法(DCVD)制得ZnO的XRD谱与标准卡片JCPDS card No.36-1451衍射峰位置及衍射峰强度基本吻合,表明生成的产物纯度很高,为晶格常数为a=0.3242Inm, c=0.51941nm的六方纤锌矿； (4)SEM表征结果表明,蒸发温度为450℃时采用干式化学气相沉积法制得的小尺寸四针状纳米ZnO针长约为200nm,针径约为15nm,这是目前为止采用气相沉积法制备纳米ZnO方法得到的最小尺寸 (5)PL表征结果表明,由于采用干式化学气相沉积法制得的四针状纳米ZnO尺寸较小,制得小尺寸四针状纳米ZnO将在可见光466nm处有效吸收光能并发生激子跃迁,绿光激发位置发生蓝移,激发强度更强,这将有利于采用干式化学气相沉积法制得小尺寸四针状纳米ZnO组装的光伏器件形成有效的电子—空穴电对。 (6)紫外可见光谱表征表明由于干式化学气相沉积法制得小尺寸四针状纳米ZnO尺寸更小,晶体结构更加规整,导致紫外可见吸收光谱波段范围更宽,吸收强度更大。 (7)当其他条件相似时,四针状纳米ZnO的尺寸越小,制备得到的各种ZnO太阳能电池的光电转化效率Eff就高,这与四针状纳米ZnO的尺寸越小,小尺寸效应越显著的理论想吻合； (8)当其他条件相似时,与四针状纳米ZnO组装成ZnO-量子点太阳能电池的光电转化效率Eff高低顺序为：CdTeCdSePbSCdS.
[Abstract]:In response to the accelerated depletion of global fossil fuels and the increasing global demand for energy , renewable energy will gradually replace conventional fossil fuel energy sources . Photovoltaic power generation in the development of solar resources has enormous potential . ZnO is a direct transition , wide bandgap material ( Eg = 3.37eV ) , high exciton binding energy ( 60meV ) , piezoelectric , conductive , transparent in visible range , high reflectivity in infrared band , etc . Thus , ZnO is widely used as transparent electrode , photovoltaic device , chemical sensor , ferroelectric memory , thermal reflector , surface acoustic wave device and low - loss waveguide , etc . of LCD or LED . Currently , solar cells are technically classified into : silicon solar cells , cadmium telluride ( CdTe ) solar cells , copper indium gallium selenide ( cigs ) thin film batteries , III - V compound solar cells , organic solar cells , dye - sensitized solar cells ( DSSC ) , and the like . On the basis of the previous methods , a method for preparing a small - sized four - needle nano - ZnO with a diameter of less than 20 nm is creatively developed , and the production rate of the small - sized four - needle nano - ZnO is greatly improved . The effect of different process parameters on the preparation of the small - sized four - needle nano ZnO sample is studied . The ZnO - CdTe solar cells prepared by dry chemical vapor deposition method were assembled into ZnO - quantum dot solar cells . The four needle - like nano - ZnO prepared by dry chemical vapor deposition method was prepared by the dry chemical vapor deposition method . The results show that : ( 1 ) Zinc evaporation temperature is the key factor affecting the morphology and size of tetrapod - like nano - ZnO . The higher the evaporation temperature of zinc , the larger the size of the four - needle nanometer ZnO . ( 2 ) it is necessary to control the whole reaction system which can not contain substances such as water molecules which can influence the morphology of the main reaction 2Zn ( g ) + O2 = 2ZnO ( g ) or the tetrapod - like nano ZnO crystal ; ( 3 ) The XRD spectrum of ZnO prepared by dry chemical vapor deposition ( DCVD ) is basically in agreement with the diffraction peak position and diffraction peak intensity of standard card JCPDS card No . 36 - 1451 , indicating that the purity of the produced product is very high , which is hexagonal fiber zinc ore with a lattice constant of a = 0.324 2Inm , c = 0.51941nm ; ( 4 ) The results of SEM indicate that the small size tetrapod nanometer ZnO needle prepared by dry chemical vapor deposition method is about 200 nm and the needle diameter is about 15nm when the evaporation temperature is 450 鈩，

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