论文标题
使用电吸附光谱法鉴定PPDT2FBT中激子的性质
Identification of the nature of excitons in PPDT2FBT using electroabsorption spectroscopy
论文作者
论文摘要
电吸收（EA）测量可用于识别有助于在光电子中应用的半导体吸收光谱的激子类型。但是，来自EA测量的推论很大程度上取决于从测量光谱中拟合和提取参数的方法。我们通过拟合多个高斯人来解构吸收光谱，并在EA光谱中获得每个吸收带的第一和第二个衍生物的相对贡献，这表明弗伦克尔，涉及激子的电荷转移或混合性质。我们检查了该方法对五苯的适用性，该方法被广泛使用且研究良好的有机半导体。我们报告了poly [（2,5-二氧基） - 苯基）-Alt-（5,6-二氟-4,7-Di（thiophen-2-基）苯甲酸[C] - [C] - [1,2,5] - thiadiazole）（ppdtt2fbt）的EA测量值。我们的分析表明，除了3.07 eV的功能外，PPDT2FBT的大多数吸收带都是混合状态，具有相对较高的电荷传递贡献。由于电荷转移激子具有较高的解离效率，因此我们推断PPDT2FBT是光伏应用的有前途的候选人。
Electroabsorption (EA) measurements can be used to identify the type of excitons contributing to the absorption spectra of semiconductors which have applications in optoelectronics. However, the inferences from the EA measurement greatly depend on the method of fitting and extraction of parameters from the measured spectra. We deconstruct the absorption spectrum by fitting multiple Gaussians and obtain the relative contribution of first and second derivative of each absorption band in EA spectrum, which gives indication of the Frenkel, charge transfer or mixed nature of the excitons involved. We check the applicability of the method for pentacene which is widely used and well studied organic semiconductor. We report EA measurements of poly[(2,5-bis(2-hexyldecyloxy)-phenylene)-alt-(5,6-difluoro-4,7-di(thiophen-2-yl)benzo[c]-[1,2,5]-thiadiazole)] (PPDT2FBT). Our analysis shows that besides the feature around 3.07 eV, which is strongly Frenkel-like, most of the absorption bands for PPDT2FBT are mixed states, having relatively high charge transfer contributions. Since charge transfer excitons have higher dissociation efficiencies, we infer PPDT2FBT to be a promising candidate for photovoltaic applications.
