【作者】 张丽娜；

【导师】 杨海滨；

【作者基本信息】 吉林大学 ， 凝聚态物理， 2012， 博士

【摘要】 在太阳能的有效利用中，太阳能电池是近年来发展最快、最具活力的研究领域之一。虽然目前开发的太阳能电池的种类很多，但仍旧存在着制备工艺复杂和环境污染等问题。提高太阳能电池的光电转换效率、降低生产成本和解决环境污染仍是人类亟待解决的问题。β-In₂S₃是一种无毒的半导体化合物，带隙宽度在2.0².3eV之间，同时具有优良的光学性能、电学性能和光电化学性能，因此在光伏器件方面具有巨大的应用潜力。目前，已表明β-In₂S₃薄膜可以作为过渡层用于CIGS太阳能电池中，来替代有毒化合物CdS，其光电转换效率可达16.4%，接近标准的CIGS电池（19.9%）。薄膜形态的In₂S₃通常采用水浴合成法来制备，并且还需要退火等处理过程，这种方法往往会造成薄膜结晶性差、附着力不好等问题。迄今为止关于In₂S₃薄膜的光电化学性质的报道还很少。针对这种现状，本论文主要进行了In₂S₃薄膜的制备研究，并对其光电化学性质进行了考察。（1）以半胱氨酸为硫源，首次采用水热合成法在FTO基底上合成了由In₂S₃薄片组装而成的薄膜。系统地研究了该薄膜的制备规律，发现薄膜的形貌可以通过控制反应时间、反应物的浓度比例和反应温度来调节，提出了其可能的生长过程。（2）对不同反应阶段的薄膜进行了光电化学性质研究，发现其具有良好的光响应特性，反应12h得到的样品的短路电流密度最大，约为0.07mA·cm^-2,6h制得的样品光电转换效率最高，为0.01%。（3）将制得的片状In₂S₃薄膜放到500℃的空气中退火即得到了纯相的In₂O₃薄膜，其形貌仍保持着In₂S₃薄膜的形貌。这说明将In₂S₃薄膜氧化是制备形貌可控的In₂O₃的一种有效的途径。（4）以硫脲为硫源，在体系中添加酒石酸，水热合成了由楔形In₂S₃颗粒组装而成的薄膜。详细探讨了酒石酸对薄膜形成的重要作用，结合不同反应阶段薄膜的形貌分析了其生长机制。光电化学性能的测试结果显示，相比于片状In₂S₃薄膜，楔形In₂S₃薄膜具有更好的光响应特性，光电流密度可以达到0.48mA·cm^-2，光电转换效率可达0.036%。（5）两步法制备TiO₂/In₂S₃核壳结构的光电极。首先采用水热合成法在FTO基底上制备了TiO₂纳米棒阵列，接下来通过连续离子层吸附和反应法（SILAR方法）在TiO₂成功沉积了In₂S₃薄层，并最终通过热处理使其晶化。光学及光电化学性能测试结果表明，In₂S₃敏化TiO₂的薄膜在可见光范围的吸收的明显增大，光电极的光响应大幅度提高，光电流可达到1.07mA·cm^-2，光电转换效率可达0.33%。探讨了其光电转换机理。更多还原

【Abstract】 Among the effective use of solar energy, photovoltaic solar cells is the fastestgrowing and the most vibrant research area in recent years. Although there are varioustypes of solar cells, complex manufacture process and environmental pollution are themain problems yet. Hence, improving the photoelectric conversion efficiency,reducing the production cost and solving the problem of the environmental pollutionare still critical issues for human beings.β-In₂S₃is a nontoxic semiconductor with band gap of2.0².3eV, which hasgreat potential for photovoltaic applications owing to its excellent optical, electricaland photoelectrochamical properties. Recently, it was reported that the CIGS solarcells prepared using β-In₂S₃as buffer layer instead of CdS showed16.4%conversionefficiency, which was close to the typical solar cell using a CdS buffer layer （19.9%）.Presently, In₂S₃thin films are prepared by chemical bath method, which generallyresult in the poor crystallinity and adhesion with the substrate. Further, theextra-annealing process would complex the preparation and increases the cost. On theother hand, there are seldom reports on the photoelectrochemical properties of In₂S₃thin films. Herein, the preparation and the photoelectrochemical properties of In₂S₃thin films were investigated. The main content and innovation of this thesis are list asfollowing:1. For the first time, the In₂S₃thin films composed of nano-/microflakes werefabricated on FTO substrate when L-cystine was used as the S source in the hydrothermal system. By investigaing the samples obtained with different experimentparameters, we found that the morphology of the films can be controlled by adjust thereaction time, the reactant contration ratio and the reation temperature. A possiblegrowth process of the films was also proposed.2. The photoeletrochemical properties of the time-dependent films wereinvestigated. It was found that the films prepared for12h achieved a photocurrentdensity of about0.07mA·cm2. However, the highest photoelectric conversionefficiency0.01%was obtained for the6h-synthesized film.3. When the In₂S₃films prepared at160℃for12h were annealed at500℃for3h, In₂O₃films with similar morphology to the In₂S₃films were obtained. Thisdemonstrated that it is an effective way to obtain the morphology-controlled In₂O₃thin films by oxiding the In₂S₃thin films.4. The In₂S₃thin films composed of wedgelike crystals were fabricated on FTOsubstrate when thiourea was used as the S source with the assistant of tartaric acid inthe hydrothermal system. The crucial role of tartaric acid on the film formation wasstudied detailedly. A possible formation mechanism of the films was also proposed byanalyzing the time-dependent thin films. The photoelectrochemical measurementresults showed a photocurrent up to0.48mA·cm^-2, which is higher than that of theflakelike In₂S₃thin films.5. The TiO₂/In₂S₃core/shell nanorod arrays photoelectrodes were prepared bytwo step method. The TiO₂nanorod array films were synthesized by a hydrothermalmethod. And In₂S₃thin films were deposited on TiO₂nanorods by SILAR method.Finally, the resulting films were annealed in N2atmosphere in order to get a bettercrystallinity. The optical and photoelectrochemical measurement results demonstratedthat the absorbance range was extensively extended in the visible light region for theIn₂S₃-sensitized TiO₂thin films, and the photo activity was enhanced significantly. Aphoto current of1.07mA·cm^-2and a photoelectric conversion efficiency of0.33%were obtained. Furthermore, the photoelectric conversion efficiency mechanism wasalso discussed.更多还原