三维ITO/金属氧化物纳米线分级结构构筑无机－有机杂化太阳能电池及性能研究

With respect to the national demand for clean and renewable energy,development of photovoltaic devices with high energy conversion efficiency and low production cost is of great importance.In this project, we propose to prepare three dimensional ITO/TiO2 and ITO/ZnO hierarchical nanowire arrays by a combination of chemical vapor deposition for ITO nanowires and subsequent solution epitaxial growth of TiO2 or ZnO， and then construct inorganic－organic hybrid bulk heterojunction solar cells with regioregular poly(3-hexylthiophene) （P3HT） molecular.This device design are advantageous in providing high contact inferface area，short carrier diffusion length as well as direct plus fast electron transport pathway. By optimizing the nanostructures design, surface sensitization with semiconductor quantum dots, surface/interface control, it is expected to enhance the light harvesting efficiency, promote the exciton separation as well as reduce the carriers recombination loss and increase the electron collection efficiency, as a result in improving the overall energy conversion efficiency; further investigations on the dynamic process of photoinduced charge carriers like transportation and recombination as well as the photophyics mechanism by a series of spectroscopy techniques such as electrochemical impedance spectroscopy and ultrafast pulse laser induced absorption spectroscopy characterizations, would reveal the key factors and underlying mechanism on the device efficiency, as a result, provide some guidance for the future design and preparation of photovoltaic devices with high efficiency、 low cost plus long lifetime and high stability.

面对国家对清洁、可再生能源需求，发展高效率、低成本光伏器件具有重要的意义。本项目拟通过结合化学气相沉积和液相外延方法制备三维有序ITO/TiO2和ITO/ZnO两种纳米线分级结构阵列，并与聚-3-己基噻吩(P3HT)构筑无机－有机杂化太阳能电池器件；该器件设计具有大的两相接触界面、短的载流子传输路径和直接快速的电子传输通道优势；通过纳米结构优化、半导体量子点敏化，表面/界面调控，以期增强光俘获效率，促进激子分离，降低载流子复合，改善电子收集效率，从而提高能量转换效率；通过一系列光谱表征手段如电化学阻抗谱和超快吸收光谱进一步研究器件光生载流子传输与复合动力学过程及光物理机制，揭示影响器件效率的关键因素和规律，为将来设计和制备高效率、低成本和长寿命高稳定性光伏器件提供理论指导。

随着全球能源需求的持续增长和对温室气体减排的关注，发展清洁、可再生新能源越来越受到关注，太阳能被认为是最有前途的清洁能源利用形式。半导体光电极结构设计与调控对太阳能电池与光电化学电池的性能具有重要的影响。本项目主要围绕太阳能电池及光解水制氢器件光电极材料设计制备、界面能级调控、光生载流子传输、收集与复合物理过程开展研究，发表SCI论文15篇，主要取得了如下研究成果：（1）利用SnO2纳米线作为透明导电电极，TiO2分支作为光活性电极材料，设计并制备了三维有序TiO2/SnO2纳米线分级结构，光电化学电池性能测试表明3D TiO2/SnO2纳米线分级结构结构由于TiO2/SnO2核-壳结构，归于其高的比面积、快速载流子传输能力和强的光散射能力。（2）设计制备了三维有序的 CdS 量子点敏化“海胆状”TiO2/ZnO 纳米棒分级结构光阳极应用于光电化学电池，测试表明CdS量子点敏化的3D TiO2/ZnO分级结构性能明显优于单一的CdS/TiO2光子晶体和CdS/ZnO纳米棒阵列，这是由于3D TiO2/ZnO纳米棒分级结构优势：高的比面积利于量子点的负载和强的光散射能力。（3）设计制备了一种三维CdS敏化海胆状TiO2纳米棒分级结构光阳极，光化学电池性能测试表明海胆状结构TiO2分级结构大幅度改善了光俘获效率和载流子收集效率。（4）成功制备了三维ZnO/Au/CdS三明治结构光子晶体，该光阳极应用于光电化学太阳能电池，测试表明ZnO/Au/CdS结构优于ZnO/Au和ZnO/CdS结构，归于Au纳米颗粒等离激元与半导体CdS量子点的协同作用，改善了光吸收和载流子传输、收集效率。