Evaluation of the capacitive behavior of 3D carbon electrodes for sub-retinal photovoltaic prosthesis
Evaluation of the capacitive behavior of 3D carbon electrodes for sub-retinal photovoltaic prosthesis
复制标题
DOI：
10.1016/j.mne.2019.02.003
复制
发表时间：
2019-03-01
影响因子：
--
通讯作者：
Hansen, Ole
中科院分区：
文献类型：
--
作者：
Davidsen, Rasmus Schmidt;Hemanth, Suhith;Hansen, Ole
在这里，我们评估微制造的 3D 热解碳电极是否适合应用于视网膜下光伏假体。这是通过测量电荷存储容量 (CSC) 和最大可注入电荷来完成的，这分别表明电极是否允许在充电周期中积累足够高的电荷，并能够提供足够快的放电以刺激神经元。碳柱的 CSC 确定为 10.9 mC/cm(2)，平面碳电极的 CSC 为 6.4 mC/cm(2)。这些值与用于视网膜刺激的最先进电极材料（例如氧化铱（IrOx））获得的值相当。最大可注入电荷由循环伏安图 (CV) 确定，平面和柱碳电极的值分别为 1.0 和 1.7 mC/cm(2)。测得的碳和 n+ 掺杂硅之间的接触电阻证实热解碳是作为 3D 电极材料集成到光伏硅视网膜植入物上的可能候选材料。通过 X 射线光电子能谱 (XPS) 分析了制备的热解碳柱的元素组成。分析表明，带有热解碳柱的 Al2O3 钝化样品仅含有铝、氧和碳，表明热解过程成功，不含任何不需要的元素。该研究表明热解碳作为视网膜、光伏植入物中 3D 电极材料的巨大潜力。
Here, we evaluate if microfabricated 3D pyrolytic carbon electrodes are suitable for application in sub-retinal photovoltaic prosthesis. This is done by measuring the charge storage capacity (CSC) and the maximum injectable charge, which indicate if the electrodes allow accumulation of sufficiently high charges in the charge cycle and are able to provide sufficiently fast discharge to stimulate neurons, respectively. The CSC was determined to 10.9 mC/cm(2) for carbon pillars and 6.4 mC/cm(2) for planar carbon electrodes. These values are comparable with values obtained for state-of-the-art electrode materials applied for retinal stimulation such as iridium oxide (IrOx). The maximum injectable charge was determined from cyclic voltammograms (CV) with values of 1.0 and 1.7 mC/cm(2) for planar and pillar carbon electrodes, respectively. The measured contact resistance between carbon and n+ doped Si confirms that pyrolytic carbon is a possible candidate for integration as a 3D electrode material on photovoltaic silicon retinal implants. The elemental composition of the fabricated pyrolytic carbon pillars was analyzed by X-ray photoelectron spectroscopy (XPS). The analysis showed that the Al2O3 passivated sample with fabricated pyrolytic carbon pillars only contained aluminum, oxygen and carbon, indicating a successful pyrolysis process without any unwanted elements. The study shows promising potential for pyrolytic carbon as a material for 3D electrodes in retinal, photovoltaic implants.