基于蜂窝状结构TiO2薄膜钙钛矿平面异质结太阳能电池

Planar heterojunction perovskite solar cells have emerged as novel all solid state solar cells with high conversion efficiencies and low cost. Their harvesting materials with high extinction coefficient and photoanodes with proper valence bands and high surface areas are important factors to guarantee their high photoelectric conversion efficiency. However, charge recombination is serious due to a large number of interface existing in mesoporous scaffold layers aggregated with nano/micro particles. Therefore, interface structure in device is an essential factor for photoelectric conversion efficiency. Transparent semiconductor film with special textrued structures can reduce optical loss effectively to enhance optical availability. However, there has no such kind of research about designing semiconductor film as photoanode for planar heterojunction perovskite solar cells according to optical principle...In this work, we plan to fabricate TiO2 semiconductor film with honeycomb structure as photoanode for planar heterojunction perovksite solar cells. This textured structure is benefited to secondary absorption of incident light for enhancing carrier generation by optimizing architecture according to optical theory and the nature of perovskite. Furthermore, the optical propagation, absorption and reflection on the interface with spherical structures, as well as charge carries generation, diffusion, and relaxation can be investigated, which can help to explore transmission mechanism of charge carries in nano scale.

钙钛矿平面异质结太阳能电池是一种高效率、低成本、全固态新型太阳能电池，所具有极高消光系数的光吸收材料和价带匹配的高比表面积光阳极或支撑层是高光电转换效率的重要因素。但介孔支撑层中纳微米粒子存在大量界面，载流子复合严重，因此器件界面构造是影响光电转换效率的重要因素。具有特定绒面结构的透明半导体薄膜增大活性材料和电子传输层的接触面积，还可有效减少光学损失，提高光的再利用，但目前尚未有运用光学理论设计特定绒面结构的器件构造结构用于钙钛矿平面异质结太阳能电池。.本课题拟以蜂窝状结构TiO2半导体薄膜作为光阳极，依据光学理论和钙钛矿吸光材料特征优化薄膜构造提高入射光二次吸收以增加载流子激发效率，修饰界面消除缺陷和针孔提高电子收集能力，并以此器件构造为研究载体，考察具有内球形界面接界处光传播、吸收、反射及器件内部载流子产生、扩散、弛豫，以纳米尺度揭示载流子的传输机制，为提高光电转换效率提供科学依据。

有机无机杂化钙钛矿具有高的宽禁带光吸收系数和较长的电子空穴输运长度，应用于光伏太阳能电池近期连续报道高光电转换效率的突破性进展，引发了科研领域对这种高性能材料研究的兴趣。为深度发掘有机无机杂化钙钛矿材料本质属性和扩展其在其他领域的应用范围，仍需进一步宏观及微观领域解析在外加光场、电场或力场的影响下钙钛矿薄膜内部及界面处的光生载流子和场激发离子与空穴的生成、复合及迁移机制。本项目在掌握了钙钛矿薄膜制备的调控方案的前提下，将其成功组装在光伏太阳能电池、纳米摩擦发电机/光感探测器、阻变忆阻器单元器件中，借助不同类型功能的器件微观领域研究钙钛矿薄膜内部光致电子/空穴对及外界场条件激发下生成的离子/空穴生成及输运机制。通过一些列各功能器件宏观电学性能测试并主要借助开尔文扫描原子力探针和导电原子力探针技术微观领域研究钙钛矿薄膜的电学特征，借助宏观及微观领域分析结果，我们发现钙钛矿薄膜表面电势高低受制于薄膜表面形貌，且同电子输运层结界处易生成耗尽区导致薄膜内部内建电场和表面电势发生变化，光生载流子易于颗粒间发生复合，使得输运模式同颗粒堆积有直接关系；外加力场导致钙钛矿薄膜表面富集正、负电荷，暴露于光场条件下激发的光致电子由电子输运层传输，导致光致空穴直接加强薄膜表面的正电荷或同负电荷发生复合；外加电场刺激下钙钛矿薄膜内部发生I-离子和空穴发生迁移及复合，最终导致钙钛矿薄膜阻抗发生变化，具有显著的阻变特征。此项目研究微观领域对钙钛矿材料在不同外加场影响下光电运行机理进行了解析，扩展了钙钛矿材料的应用范畴。