中文摘要：

为了深入研究异质结复合体系中光生电荷分离与传输机制以及主要影响因素,采用水热法在不锈钢滤网上分别制备出Zn2SnO4菱形纳米颗粒和有序纳米线,以Zn2SnO4两种不同微结构与ZnFe2O4无机敏化剂制备成Zn2SnO4/ZnFe2O4异质结。XRD检测结果表明,异质结构中两组分都达到了良好的结晶状态;同时,两复合体系都呈现出异质结复合结构的光吸收特性。稳态表面光电压测试结果表明两异质结构具有优于单一组分的光伏响应特性,而且,光伏性质呈现出Zn2SnO4有序纳米线/ZnFe2O4优于Zn2SnO4菱形纳米颗粒/ZnFe2O4的特点。较弱正外电场诱导下,两复合薄膜仍然保持稳态下的光伏响应特性;随着外电场逐步提高,Zn2SnO4菱形纳米颗粒/ZnFe2O4光伏性质增加非常明显,在＋2V电压诱导下,Zn2SnO4菱形纳米颗粒/ZnFe2O4已接近Zn2SnO4有序纳米线/ZnFe2O4的光伏响应强度。实验结果表明光阳极微结构、载流子浓度、自由电荷扩散长度、空间电荷区厚度、内建电场和能级匹配对光生电荷分离和传输有直接的影响。

英文摘要：

In order to further study the separation and transport mechanism of photogenerated charges,and the main influence factors in heterojunctions composite system, Zn2SnO4 rhombic nanoparticles and order nanowires were synthesized on stainless steel filters by hydrothermal method. Zn2SnO4 / ZnFe2O4 heterojunctions were prepared with two kinds of different Zn2SnO4 microstructures and ZnFe2O4 as inorganic sensitizer.XRD results indicate that two components of heterojunction sturcture can be a good crystalline state,at the same time,two heterojunctions all present the absorption characteristics of composite structure. The signals of steady state surface photovoltage indicate that two heterostructures exhibit the higher photovoltaic response than two components. Moreover,Zn2SnO4 nanowires / ZnFe2O4 presents the higher photovoltaic response than Zn2SnO4 nanoparticles / ZnFe2O4. Under the lower positive bias,two heterojunctions have the same surface photovoltage as the steady state. With the bias increasing,the photovoltaic response of Zn2SnO4 nanoparticles /ZnFe2O4 enhances quickly. Under bias of ＋ 2 V,Zn2SnO4 nanoparticles / ZnFe2O4 exhibits the similar photovoltaic signal with Zn2SnO4 nanowires / ZnFe2O4. It is suggested that photoanode microstructure,density of carrier,free charges diffusion length,thickness of surface space charge region,build-in electric field and energy level matching have a direct effect on the separation and transport of photogenerated charges.