基于新型交联聚合物电解质的准固态染料敏化太阳能电池

采用柠檬酸(CA)交联聚乙二醇(oligo-PEG, 平均分子量M_w=200, 400, 1000, 2000), 合成具有可生物降解性能的聚柠檬酸-乙二醇(PCE)交联聚酯, 并以此为基体材料制备得到准固态的三维交联型PCE/LiI/I₂聚合物电解质. 采用红外吸收光谱(IR)、核磁共振氢谱(¹H-NMR)、扫描电镜(SEM)和Raman光谱分别对PCE基体的分子结构、聚合物电解质的微观形貌以及导电离子对的存在形式进行表征; 通过线性扫描伏安法(LSV)研究了聚合物电解质的离子扩散系数、电导率以及电池的输出电流-电压(I-V)性能. 结果表明, PEG的分子量影响PCE基体膜的微观形貌及其吸液性能, 从而影响聚合物电解质的离子导电性能及电池的光电性能: 随着PEG分子量M_w从200, 400, 1000增大到2000, PCE基体膜的结构变得疏松, 吸液率增加, 吸液溶胀后的基体中I-3的跃迁活化能降低, 导致电解质的电导率和电池的短路光电流密度随之增加; 在60 mW·cm^-2的入射光强下, 四种电解质对应电池的光电转化效率依次为3.26%、3.34%、4.26%和4.89%.

Quasi-Solid State Dye-Sensitized Solar Cells Based on the Novel Crosslinked Polymer Electrolyte

A quasi-solid-state three-dimensionally crosslinked poly(citric acid-ethylene glycol) (PCE)/ LiI/I₂ polymer electrolyte has been prepared using biodegradable PCE synthesized via a crosslinking reaction between citric acid (CA) and oligo-polyethylene glycol (PEG) (average molecular weight M_w= 200, 400, 1000, 2000) as a matrix. The molecular structure of the PCE matrix, micro-morphology of polymer electrolyte, and the state of conductive ion-pairs in the electrolyte were characterized by infrared (IR) spectrum, 1H nuclear magnetic resonance (1H-NMR), and Raman spectroscopy, as well as scanning electron microscopy (SEM). The ionic diffusion coefficient and conductivity of polymer electrolytes and the output current-voltage (I-V) properties of the cells were investigated via linear sweep voltammetry. The results reveal that PEG molecular weights influence the mesh morphology and the absorbent properties of the PCE matrix, which influences the polymer electrolyte ionic conductive performance and the photoelectric performance of the cells. As PEG molecular weights increased from 200, 400, 1000 to 2000, the PCE matrix mesh structure became looser, the liquid electrolyte uptake of the matrix increased, and the transition activation energies of I₃^- in the swollen PCE matrix decreased, which led to an increase in the electrolyte conductivity and the short circuit photocurrent densities of the cells accordingly. The photoelectric conversion efficiencies of the cells assembled by the four polymer electrolytes above were 3.26%, 3.34%, 4.26%, and 4.89%, respectively, under an incident light intensity of 60 mW·cm^-2.