表面态和线间距对ZnO纳米线/聚(3-己基噻吩)复合纳米结构光伏性能的影响

Size dependence of photovoltaic properties and surface states modulation in ZnO nanowire/poly(3-hexylthiophene) hybrid nanostructures

基于导电聚合物的有机光伏器件具有低成本、重量轻和柔性等优点.然而,相对于无机材料而言,其载流子迁移率较低.引入高迁移率的无机材料和导电聚合物构筑复合形成混相的异质结结构可以有效解决此问题.通过此种方式,在导电聚合物中产生的激子不需要传输过长的距离到达施主/受主界面,电荷分离过程能够发生在光活性层中的有机/无机材料界面.

An appropriate diameter and wire-to-wire distance is critical for optimizing the performance of hybrid inorganic/organic photovoltaic devices. For a deep understanding of their influences on such hybrid structures, the well-ordered ZnO nanowires with different diameters are fabricated by the versatile hydrothermal growth. The dependence of the photovoltaic performance on the surface states, wire diameter and wire-to-wire distance is investigated. We demonstrate that the pristine thick ZnO nanowires film possess a higher surface photovoltage(SPV) response than the thin one. This is mainly due to the influence of surface states on the thin ZnO nanowires, which can capture the photo-generated carriers. When the two kinds of ZnO nanowires are fabricated into a hybrid inorganic/organic structure, the thin ZnO nanowires/poly(3-hexylthiophene)hybrid film has a higher SPV response than the thick one,which is contrary to the pristine ZnO nanowires. This is benefited from the smaller diameter and wire-to-wire distance of the thin ZnO nanowires owned. The crystallinity,wire diameter and wire-to-wire distance have the crucial influence on the final photovoltaic performance. The results shown here give us insights toward designing efficient hybrid photovoltaic devices.