Leu Yow-An, Lu Yen-An, Yeh Min-Hsin, Shih Po-Ta, Shen Sheng-Yen, Ho Kuo-Chuan, Lin Jiang-Jen
Department of Chemical Engineering , National Taiwan University of Science and Technology , Taipei 10607 , Taiwan.
ACS Appl Mater Interfaces. 2018 Nov 7;10(44):38394-38403. doi: 10.1021/acsami.8b09852. Epub 2018 Oct 26.
A family of new polymeric dispersants, branched poly(oxyethylene)-segmented esters of trimellitic anhydride adduct (polyethylene glycol-trimethylolpropane-trimellitic anhydride, designated as PTT), were synthesized and utilized to homogeneously disperse TiO nanoparticles. The weight fraction of poly(oxyethylene)-segment in the dispersants and the molecular architecture in favoring the branched shape are two predominant factors for designing the effective dispersants. In particular, the poly(oxyethylene) block of 1000 g/mol from PEG1000 as the starting material and a total molecular weight of 12 000 g/mol have constituted the polymeric dispersants for the best performance for homogenizing TiO nanoparticles. The dispersant structures were characterized by using Fourier-transform infrared spectroscopy, acid value determination, and gel permeation chromatography. The TiO dispersibility was evaluated by dynamic light scattering and transmission electron microscopy. The synthesized dispersants were utilized to homogenize the as-prepared TiO, further fabricated into films of photoanodes for dye-sensitized solar cells (DSSCs). The ultimate performance of DSSC was measured to be 8.17 ± 0.13% for the device efficiency (η) which was significantly higher than the conventional TiO photoanode at η = 7.14 ± 0.12%. The photoanode film was characterized by X-ray diffraction, Brunauer-Emmett-Teller surface area, and dye-loading amount measurements. The kinetics of photogenerated electron in the photoanode, including electron lifetime and electron transit time of the film, was studied via electrochemical impedance spectroscopy, intensity-modulated photocurrent spectroscopy, and intensity-modulated photovoltage spectroscopy.
合成了一类新型的聚合物分散剂，即偏苯三酸酐加合物的支化聚（氧乙烯）嵌段酯（聚乙二醇-三羟甲基丙烷-偏苯三酸酐，命名为PTT），并用于均匀分散TiO纳米颗粒。分散剂中聚（氧乙烯）嵌段的重量分数以及有利于支化形状的分子结构是设计有效分散剂的两个主要因素。特别地，以PEG1000中1000 g/mol的聚（氧乙烯）嵌段为起始原料，总分子量为12000 g/mol，构成了用于均匀化TiO纳米颗粒的性能最佳的聚合物分散剂。通过傅里叶变换红外光谱、酸值测定和凝胶渗透色谱对分散剂结构进行了表征。通过动态光散射和透射电子显微镜对TiO的分散性进行了评估。将合成的分散剂用于均匀化制备的TiO，进一步制成染料敏化太阳能电池（DSSC）的光阳极薄膜。测得DSSC的最终器件效率（η）为8.17±0.13%，显著高于传统TiO光阳极的7.14±0.12%。通过X射线衍射、布鲁诺尔-埃米特-泰勒表面积和染料负载量测量对光阳极薄膜进行了表征。通过电化学阻抗谱、强度调制光电流谱和强度调制光电压谱研究了光阳极中光生电子的动力学，包括电子寿命和薄膜的电子传输时间。
