咔唑-噻吩基D-π-A卟啉敏化剂的设计、合成及其在染料敏化太阳能电池中的应用

Dye-sensitized solar cells (DSSCs) have attracted great attention due to their ease of fabrication, low cost, and high light-to-electricity conversion efficiencies compared with those of commercial silicon solar cells. The approach of this project is to expand and enhance the sunlight absorption of the sensitizer, suppress the recombination of electrons and holes in photoinduced electron transfer process. The porphyrin sensitizers with a D-π-A structure, in which π ?represents a porphyrin-thiophene π-conjugation bridge serving as a spacer between the carbazole donor D and the carboxyl anchoring group A, were designed and will be synthesized based on the theoretic calculation using Gaussian. The synthesized porphyrin dyes are used as photosensitizers to fabricate the sandwich-type two-electrode DSSCs. The influences on the photoelectric conversion properties of the sensitizers will be investigated. And the improvement in the performance of photovoltaic cells due to the synergy of carbazole and thiophene will also be studied. In order to obtain the microscopic interpretation of the influences and the micro-mechanism of carbazole as electron donor and hole transport materials in the process of electron transport, the molecular orbital compositions of the ground states and excited states, electron density distribution, charge population, and other properties will be calculated by density functional theory (DFT) and the time dependent density functional theory (TD-DFT). This research will provide an important scientific basis for designing the efficient porphyrin sensitizers and their practical application.

与硅太阳能电池相比，染料敏化太阳能电池因制备工艺简单、成本低和较高的光电转换效率而备受关注。本项目以拓宽和增强敏化剂对太阳光的吸收、抑制光诱导电子转移过程中电子和空穴的复合为思路，基于Gaussian理论计算，设计、合成以卟啉-噻吩π桥连接具有强给电子特性和空穴传输功能的咔唑给体（D）、羧酸受体（A）形成的D-π-A型卟啉敏化剂。利用两电极法构建"三明治"式染料敏化太阳能电池。研究引入咔唑、噻吩对敏化剂光电转换性质的影响，并研究咔唑和噻吩的协同作用对光伏电池性能的改善。利用密度泛函（DFT）和含时密度泛函（TD-DFT）计算分子基态和激发态的分子轨道成分、电子云密度分布、电荷布居等性质，微观上解释咔唑和噻吩引入卟啉环后对光电性质的影响，探索咔唑作为给体和空穴传输材料在电子转移过程中的微观机制。本课题的研究将为设计高效的卟啉敏化剂和该类敏化剂的实际应用提供重要的科学依据。

染料敏化太阳能电池具有成本低和相对较高的转换效率而成为国际研究的热点之一。本项目设计合成了具有优良光伏性能的D-π-A型卟啉敏化剂，研究了DPQ位置对光物理、电化学、光电性质、催化活性等的影响，同时研究了α-Fe2O3/RGO复合物材料的电催化活性和光伏行为。. (1) 缺电子的2,3-二苯基喹喔啉 (DPQ)被引入卟啉敏化剂(FNE57)的不同位置，构建了 D-A’-Por-π-A (FNE58) 和 D-Por-A’-π-A (FNE59) 敏化剂。基于不同位置DPQ的卟啉敏化剂对准固态电池的光电性质被系统研究。理论计算表明， 键合 DPQ 单元与受体附近，有利于电子离域在LUMO，提高电子的不对称性从而利于分子内电荷转移。结果表明，FNE59敏化的准固态电池获6.02%的光电转化效率, 比FNE57和FNE58敏化的电池分别提高了23%和51%。. (2)为了在可见区获得宽的光谱响应，采用共敏化剂FNE57 + FNE46和FNE59 + FNE46敏化的准固态电池分别获得7.88%和8.14%的转换效率，高于单个敏化剂敏化的电池。共敏化后，短路光电流的提高是两个敏化剂互相弥补了在可见区的吸收所致。开路光电压介于卟啉和有剂染料敏化的电池之间，这是由于电子寿命的不同所致。重要的是FNE59 + FNE46敏化的电池具有良好的稳定性。. (3) 为了开拓卟啉敏化剂在其他领域中的应用，将其与四丁基溴化铵（TOAB）相互作用的混合物滴涂于玻碳电极表面(TOAB/FNE59/GCE)，获得新颖的非酶电化学传感器。该传感器对H2O2和亚硝酸盐表现出优越的电催化活性、高的灵敏性和好的稳定性。 . (4) 以硝酸铁为原料， 通过水热法制备了α-Fe2O3纳米粒子和α-Fe2O3@RGO纳米复合材料。α-Fe2O3@RGO提高的电导率及α-Fe2O3和RGO之间积极的协同作用，在对催化还原I3-表现出优异的电催化活性。该材料用于染料敏化电池的对电极材料获得了7.02%的效率。