【作者】 蒲源；

【导师】 李葵英；

【作者基本信息】 燕山大学 ， 材料物理与化学， 2006， 硕士

【摘要】 本文使用自行设计并安装的一套提拉膜设备,利用溶胶-凝胶提拉法制备出了合乎要求的La_0.8Sr_0.2FeO₃纳米薄膜。与其他方法相比,提拉制膜方法既简便易行又节约能源。测试结果表明,与相同粒径该粉体材料相比,薄膜材料最大光伏响应的波长范围发生明显的蓝移现象,这说明该纳米薄膜材料具有更加独特的表面光伏特性和表面电子结构。利用柠檬酸法制备的过渡金属复合氧化物La_0.8Sr_0.2FeO₃,通过改变固相反应条件控制其粒径大小。利用光声光谱和表面光电压谱研究了两种不同粒径nano-La_0.8Sr_0.2FeO₃的光致电荷跃迁机制和能量转换行为。根据测试结果研究了不同粒径该材料的表面电子结构。同时,利用低真空环境下的表面光电压谱研究了在真空环境下样品的光激发电荷转移行为。分析发现,当粒径小于10 nm时,La_0.8Sr_0.2FeO₃表现出了更加明显的表面效应,这一现象充分证实了前面所得结论的正确性。研究结果表明,不同粒径的La_0.8Sr_0.2FeO₃的表面光电压谱及光声光谱不仅响应曲线的峰型发生变化,其响应范围及响应强度也存在明显的差异,这充分体现了纳米材料的量子尺寸效应和表面效应。场诱导表面光电压谱的结果证实该材料具有p型光伏特征,随着粒径的增大其p型光伏特性增强。研究结果说明,薄膜的制备可以大大拓宽该材料实际应用领域。更多还原

【Abstract】 Nano-La_0.8Sr_0.2FeO₃ thin film was prepared by a dip-coating machinemade by ourselves. Comparing with other methods, this is easier to operate.What’s more, this can save energy sources. The result shows that shift toshortwave exists in Surface Photovoltage Spectroscopy （SPS） respondingrange of thin film comparing with SPS of powder with same particle size. Thisshows that inimitable photovoltage characters and structure of surfaceelectrons appeared in this thin film.The transition metal complex oxide nano-La_0.8Sr_0.2FeO₃ was synthesizedwith citrate method. The size of the particles is controlled by the conditions ofsolid reaction. The photoexcited transition mechanism, the energy conversionbehaviors and the structure of surface electrons of La_0.8Sr_0.2FeO₃ withdifferent particle size were studied by SPS and Photo acoustic Spectroscopy（PAS）. SPS in vacuum was discussed too. More obvious surface effect willappear when the particle size of La_0.8Sr_0.2FeO₃ is less than 10 nm. Thisphenomenon proved the correctness of the conclusion mentioned before.The result shows that the shape of respnding peak changed in SPS andPAS of La_0.8Sr_0.2FeO₃ with different particle-size. Differences existed in SPSresponding range and intensity which can be explained by quantum effect andsurface effect. The characters of p-type photovoltage in this material isrepresented in electric field induced SPS （EFISPS）. The characters of p-typephotovoltage will enhance as the augment of particle size.The prearation of thin film can enlarge the application field of thismaterial by the studies and findings.更多还原