【作者】 王正平；

【导师】 张密林；

【作者基本信息】 哈尔滨工程大学 ， 材料学， 2008， 博士

【摘要】 二氧化钛（TiO₂）由于其优异的光电转换及物化性能成为半导体光电材料的研究热点，在光电子器件、环境污水处理、空气净化、防雾抗菌材料等方面得到广泛应用与研究。在能量大于其禁带宽度的光照射下，二氧化钛产生电子与空穴对，光生电子迁移至材料的表面，使载流子有效分离，实现二氧化钛（TiO₂）电极的光电转换。在环境保护方面，光生电子迁移产生的光生空穴的强氧化能力以及导带电子的还原能力使其能有效地氧化还原大部分有机物及一些金属离子，在环境污染的治理方面具有重大意义。因此，研究和制备性能优良的功能性二氧化钛材料是一项十分有意义的工作。本论文应用溶胶-凝胶法（Sol-gel），配合丝网印刷技术，制备具有优良性能敏化纳晶TiO₂多孔薄膜电极，并采用场发射扫描电镜（SEM），X-射线衍射（XRD）、高分辨电镜（HRTEM）、太阳能电池光谱测试系统等测试手段，对采用丝网印刷制备的敏化纳晶TiO₂多孔薄膜电极的表面微观特征及光电性能进行了表征。同时，利用溶胶-凝胶法结合紫外光助合成的TiO₂光催化材料，用X-射线衍射（XRD）、激光拉曼光谱（Laser Raman）、X-射线光电子能谱（XPS）、高分辨电镜（HRTEM）等测试手段，对光助合成的TiO₂粉末进行结构测试，并与传统溶胶-凝胶法制备的样品相比，得到一些有意义的研究结果。上述二个方面为有效地利用太阳光能源研究提供了积极的研究思路与方向，为解决可见光催化问题提供了新的途径。本论文主要研究以下几方面的工作：利用溶胶凝-胶法制备出了染料敏化纳晶TiO₂多孔薄膜电极，对其制备工艺进行研究表明，当TiO₂胶体含量为15％，并且薄膜电极的厚度为7～9μm时，利用涂敷法制备的薄膜电极组装的太阳能电池光电性能较好，其光电转换效率达到了4．6％。在此基础上，将溶胶-凝胶法与丝网印刷技术相结合制备出了纳晶TiO₂多孔薄膜电极。通过对纳晶TiO₂多孔薄膜电极的光电性能参数进行比较发现，利用乙基纤维素为增稠剂所制备的薄膜电极的性能相对比较优越，所组装的太阳能电池光电转换效率达到了5．05％。在利用乙基纤维素做粘稠剂的基础上添加三种（AS、BT和C3）流平剂时，电池的光电转换效率均达到了5．27％。通过对TiO₂的固含量、丝网目数、网印次数、水热时间、反应环境、烧结程序的控制等工艺参数的考察，确定了制备染料敏化纳晶TiO₂多孔薄膜电极的最佳工艺参数。所组装的染料敏化太阳能电池光电转换效率可达到6．25％。在此基础之上，对染料敏化纳晶TiO₂多孔薄膜电极的表面进行修饰，使电极的光电转换效率由处理前的5．27％增加到6．72％。将紫外光辐射引入到溶胶-凝胶法过程的溶胶阶段，紫外光的引入促进了TiO₂从无定形态向锐钛矿相转变的晶型形成，在100℃的烧结温度就制得锐钛矿型二氧化钛催化剂，具有较小的粒径分布和较大的比表面积，显著地提高了锐钛矿颗粒的晶化程度。光助合成的TiO₂复合型催化剂，在可见光区有明显的光谱响应，在可见光催化降解多种有机污染物分子，通过紫外光催化降解罗丹明B溶液考察了样品的光催化活性，结果显示光助样品的催化活性比非光助样品明显的高。上述研究结果显示出在合成与调控制备功能性TiO₂半导体材料方面，利用传统溶胶-凝胶方法，从不同的角度将相关技术与传统溶胶-凝胶法有机的结合在一起，为有效地研究和应用开发TiO₂半导体光电转化材料进行了有意义的尝试。更多还原

【Abstract】 Titanium dioxide（TiO₂） has attracted great attentions as a photoelectricsemiconductor material due to its excellent photoelectric conversion ability andphysicochemical property. It has been widely investigated and employed in manyfelds such as optoelectronic device, wastewater treatment, air purification andantifogging antibacterial material.When exposed to the light which has morepower than its band gap, TiO₂ produces electrons and hole pairs, thephotoelectrons transfer to the surface of the material and then the separation of thephoto-generated carriers and the photoelectric conversion of TiO₂ electrode arerealized. Most of the organic compounds and some metal ions can be oxidized andreduced effectively because of the strong oxidative ability of the photoholesproduced by the transference of photoelectrons and the reductive ability of theconduction band electrons, which has a vital meaning in the field of environmentprotection. Consequently, the investigation and preparation of functional TiO₂materials with proper characteristics are very meaningful works.In this thesis, sensitized nanocrystalline TiO₂ porous film photoelectrodeswith excellent properties were prepared via sol-gel method and screen printingtechnique. Its surface microscopic characteristics and photoelectricity werecharacterized by field emission scanning electron microscope, x-ray diffraction,high resolution electron microscopy, solar energy battery spectrum, etc.Meanwhile, TiO₂ photocatalysis material was synthesized via sol-gel method andultraviolet photo-assisted method, which was also characterized by x-raydiffraction, laser raman spectrum, x-ray photoelectron spectroscopy, highresolution electron microscopy, field emission scanning electron microscope,etc.And many significant results were gained by comparing the structure and theperformance with traditional ones synthesized via sol-gel method.The two aspects mentioned above provided affirmative mind and direction to use sunlighteffectively, and offered a new method to solve questions of visible-lightphotocatalysis properly.Dye-sensitized nanocrystalline TiO₂ porous film photoelectrodes wereprepared via sol-gel method. The investigation of the preparing process showedthat the photoelectric properties of the solar cells composed of film electrodeprepared via coating method were outstanding on the condition that the colloidcontent was 15% and the thickness of the film electrode was 7～9μm, and thephotoelectric conversion efficiency could reach 4.6%.nanocrystalline TiO₂ porousfilm photoelectrodes were prepared via sol-gel method and screen printingtechnique. The property of the film electrode prepared using ethyl cellulose asthickener was better and the photoelectric conversion efficiencythe of the solarcells prepared by which is about 5.05%. The results also showed that thephotoelectric conversion efficiency of the TiO₂ porous film electrode made ofethyl cellulosic thichener, rheological angent （AS, BT and C3） could be 5.27%respectively.the optimum technological parameters were decided through a largequantity of experimental studies such as the optimization of solid content of TiO₂,eyelet number, screen printing times, hydrothermal time, reaction environment,sintering procedure, and the choice of electrolytes. The photoelectric conversionefficiency with the optimized film electrode could be 6.25%. And thephotoelectric conversion efficiency could be increased from 5.27% to 6.72%when the surface of the dye-sensitized nanocrystalline TiO₂ porous filmphotoelectrodes were modified.The introducing of the ultraviolet radiation into the sol-gel process promotedthe transformation of TiO₂ from amorphous structure to anatase phase, anataseTiO₂ catalyst could be prepared at 100℃and the crystallization degree of theanatase particle was increased significantly with less particle size distribution and larger specific surface area.TiO₂compound catalyst synthesized using aphoto-assisted technique had obvious spectral response in the visible region andcould catalyzed degrade many kinds of organic pollutant molecules.Photo-catalytic activity was studied by observing the ultraviolet photocatalysisdegradation of rhodamine B, and the result showed that the catalytic activity ofthe photo-assisted samples were obviously higher than that of normal ones.The results and conclusions above showed that the integration of the relatedtechnology and the traditional sol-gel method from different angles in the field oftunable synthesis of TiO₂ semiconducting material with high activity providedmeaningful theoretical research and exploration for developing and utilizing thephotoelectric material and the photocatalysis material effectively.更多还原