宽光谱可排列多层共敏化薄膜太阳电池构建及其载流子传输动力学研究

Co-sensitized TiO2 film containing different types of dye adsorption layers can broaden the absorption spectrum of dye-sensitized solar cells (DSC) and improve the photoelectric conversion efficiency simultaneously. However, there are some problems needing to be solved, such as difficultly controlling the thickness of the dye adsorption layer, unabling freely arranged the order among dye adsorption layers, and less than the demand of dye adsorption. These problems limit the optimization of co-sensitized film structure and further broaden the absorption spectrum. From the perspective of dye desorption, this project proposes a new idea for preparating a novel co-sensitized film based on short-range screening mechanism involved that electrolyte cations acting on the potential distribution in TiO2 film. The short-range screening mechanism about potential distribution is investigated and the method of controlling electric potential distribution depth is obtained in this project. The ingenious designed dye desorption system will be used to obtain blank layer for subsequent dye adsorption sites in the different position of the dyed-TiO2 film. The thickness of blank layer could be controlled and three adsorption layer positioning modes will be obtained. The co-sensitized film containing several adsorption layers and thickness of each layer could be controlled.The order of different kind of sensitized layer could be arranged by varying the order of "sensitized-desorption-sensitized". This method provides a new perspective to facilitate further optimization of the co-sensitized film structure. The electron transport mechanism will be studied and the limitation processes for cells performance will be found out in order to improve the performance of the co-sensitized film.

含有不同染料吸附层的共敏化薄膜可拓宽太阳电池吸收光谱提高效率。目前主要通过染料自发吸附来制备，其缺点是以牺牲前一种染料的吸附量为代价为后续染料提供吸附空间，同时还存在吸附层数少和层间不能排列等问题，限制了共敏化薄膜性能的进一步提升。本项目从染料自发吸附的逆向角度，提出基于薄膜内部电势分布的短程屏蔽效应来构建共敏化薄膜的新学术思想，拟解决以往依赖染料自发吸附制备带来的矛盾。项目首先定量揭示电势分布的短程屏蔽效应，实现电势分布可控；其次，明晰电势分布区域内的染料解吸附机理，借助自行设计的染料解吸附系统在薄膜不同位置解吸附出厚度可控的解吸附层，实现多种解吸附层定位模式；再次，通过后续循环敏化过程和优化薄膜吸光结构，获得层厚可控、层间可排列的新型多层共敏化薄膜；最后，研究载流子传输机理，调控微观动力学过程，最大限度提高共敏化薄膜的光电性能。本项目将为制备高性能共敏化太阳电池核心材料提供新思路。

针对目前主要依赖染料自发吸附制备共敏化薄膜的现状，本项目计划书提出从染料吸附逆过程—解吸附角度出发，基于一个物理效应，拟利用电化学方法制备高性能共敏化薄膜材料并研究其光电性能，实现多学科交叉融合。在执行期内，本项目按照既定研究计划完成了所有研究内容，实现了研究目标。通过基于染料脱附数量来建立电势分布模型，完成了纳米薄膜内部电势短程屏蔽的理论研究。建立了负偏压下电解吸附染料系统，对系统的电化学参数如参比电极筛选，电势校正，电解液的阳离子筛选等等进行了研究。发明了染料解吸附层在纳米薄膜中定位的关键技术，获得了发明专利授权。详细研究染料在负电势作用下的解吸附机理和动力学。将电化学石英晶体微天平（EQCM）应用到纳米表面染料分子解吸附定量研究中，在恒电位和变电位的条件下原位获得染料解吸附量。选择经典的钌基染料，实现了纳米薄膜内部不同染料吸附层自由排列。成功制备了两种吸附层自由排列的共敏化薄膜，验证了申请书中的实验设想。利用电化学阻抗谱（EIS），开路电压衰减谱（OPVD）等手段研究了电子在纳米颗粒薄膜中的传输和复合机制。同时基于本项目取得理论和技术基础，将连续电解吸附-再敏化这种技术，应用到电池器件寿命再生之中，成功的将器件寿命恢复。这个是原计划任务中的延续和扩展。将来这个内容的继续研究对电池的实际应用有着重要意义。项目在执行的四年中获得较多的成果：资助发表第一作者或通讯作者SCI论文5篇，其中SCI一区收录3篇。执行期间申请技术专利7项，其中授权5项，参与学术交流4次，会议报告2项，分会论坛主席1次。培养硕士研究生6名，毕业5名，在读1名。