Ultrafast Transient Absorption Spectroscopy of Inkjet-Printed Graphene and Aerosol Gel Graphene Films: Effect of Oxygen and Morphology on Carrier Relaxation Dynamics
Ultrafast Transient Absorption Spectroscopy of Inkjet-Printed Graphene and Aerosol Gel Graphene Films: Effect of Oxygen and Morphology on Carrier Relaxation Dynamics
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DOI：
10.1021/acs.jpcc.2c01086
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发表时间：
2022-05-12
影响因子：
3.7
通讯作者：
Chauvet, Adrien A. P.
中科院分区：
文献类型：
--
作者：
Auty, Alexander J.;Mansouriboroujeni, Negar;Chauvet, Adrien A. P.
纳米结构石墨烯的可调电子特性使其成为新技术应用中最受欢迎的金属替代品之一。特别地，从这些纳米结构制备油墨的能力允许可印刷的并且因此可扩展的基于石墨烯的电子器件。在这里，我们研究了新型喷墨打印气溶胶凝胶石墨烯（AG）薄膜的电子特性，并将其与喷墨打印石墨烯（G）薄膜进行了比较。更具体地说，我们通过超快瞬态吸收光谱报告这些材料的光致载流子动力学。与石墨烯相比，AG膜具有更高的氧含量以及复杂的3D形态。虽然G和AG在组成和结构上都不同，但它们的载流子-光学声子散射率（在74-140 fs范围内）的相似性表明了相当的晶格缺陷密度。因此，与电子相关的不是缺陷的数量，而是缺陷的类型。事实上，在比较G膜，表现出完全恢复的瞬态信号，AG膜表现出只有部分恢复在我们的400 ps的实验时间窗口。持续的信号被分配给捕获的电子状态。这些长寿命的电子态很可能是由于氧的存在，而不是由于薄膜独特的3D形态。
The tunable electronic properties of nanostructured graphene make it one of the most sought alternatives to metals for novel technological applications. In particular, the ability to prepare inks out of these nanostnictures allows for printable and thus scalable graphene-based electronics. Here, we investigate the electronic properties of novel inkjet-printed aerosol gel graphene (AG) films and compare them to those of inkjet-printed graphene (G) films. More specifically, we report on the photoinduced carrier dynamics of these materials via ultrafast transient absorption spectroscopy. In comparison to graphene, AG films have a higher oxygen content as well as a complex 3D morphology. While G and AG both differ in composition and structure, the similitude in their carrier-optical phonon scatter rates (in 74-140 fs range) indicates a comparable lattice defect density. It is therefore not the number of defects but the type of defect that is electronically relevant. Indeed, in comparison to G films, which exhibit complete recovery of the transient signal, the AG films exhibit only partial recovery within our 400 ps experimental time window. The persisting signal is assigned to trapped electronic states. These long-lived electronic states are most probably due to the presence of oxygen rather than due to the films' unique 3D morphology.