Interfaces and Charge Transport in Melanin Thin Films and Devices

限制世界范围内废弃电子电气设备(WEEE)的需要，开发“无处不在的传感器网络”的兴趣，改善医疗植入物和活组织之间的生物兼容性的要求，都要求对自然材料进行彻底研究，这些材料对环境和人类友好，资源丰富，可低成本获得。在这种情况下，黑色素是一个有吸引力的候选者。 黑色素在动植物中普遍存在。例如，它可以在人的皮肤、头发、眼睛、内耳和大脑中发现。真黑素是所有黑色素中研究最多的一种，具有多种功能，包括光保护、金属螯合、抗氧化行为和清除自由基。真黑素还与黑色素瘤、皮肤癌和帕金森氏症的发生有关。除了在生物学和医学上的重要性外，真黑素还因为其物理化学性质，如光导性和水合电导性而受到物理学家和材料科学家的研究。这些性质，加上生物相容性、生物降解性和非凡的热稳定性和光稳定性，表明了真黑素在技术应用方面的巨大潜力。 尽管在薄膜形式的真黑素的加工方面取得了令人印象深刻的进展-众所周知，真黑素在所有溶剂中都很难溶解-但要推进对真黑素功能特性的理解并开发其技术潜力，必须克服主要障碍。关于颜料的大分子和超分子结构的模糊定义以及电荷转移和传输特性的方面还没有完全了解。 我在这笔发现基金中提出的研究计划旨在促进有关真黑素薄膜中电子和离子传输的知识，这与其结构有关。我将采用一个整体的方法，包括化学、结构、氧化还原、电子和离子贡献，我相信这是研究复杂的自然材料的理想平台，这些材料的行为受到外部因素(例如大气的组成或盐的存在)的显著影响。研究的跨学科性将使我们能够培养多才多艺的高素质人才，真正的“问题解决者”，能够面对我们现代的重大挑战。 我的研究将产生指导方针，在黑色素和其他类别的天然材料中建立扩展的结构-性质关系，用于环境友好的电子设备和生物电子设备，例如用于储能的生物兼容和可生物降解的超级电容器，化学和生物传感器，具有更好的生物兼容性的植入式神经电极，并将推动 了解真黑素在生物系统中的功能性质。

The need to limit the waste electrical and electronic equipment (WEEE) worldwide, the interest in developing a "ubiquitous sensor network", the requirement for an improved biocompatibility between medical implants and living tissues call for a thorough study of natural materials, environmentally and human friendly, abundant and available at low-cost. Within this context, the pigment melanin is an attractive candidate. Melanin is ubiquitous in flora and fauna. As an example, it can be found in human skin, hair, eyes, inner ear and brain. Eumelanin, the most studied of all classes of melanin, has numerous functions that include photoprotection, metal chelation, antioxidant behavior and free radical scavenging. Eumelanin is also involved in the development of melanoma skin cancer and Parkinson's disease. Apart from its importance in biology and medicine, eumelanin has been investigated by physicists and materials scientists because of its physicochemical properties, e.g. photoconductivity and hydration-dependent conductivity. These properties, together with biocompatibility, biodegradability and extraordinary thermal and photostability, indicate the great potential of eumelanin for technological applications. Despite impressive progress done in the processing of eumelanin - notoriously poorly soluble in all solvents - in film form, major hurdles have to be overcome to advance the understanding of the eumelanin functional properties and to exploit its technological potential. Aspects pertaining to the ill-defined macro and supramolecular structure of the pigment as well as to charge transfer and transport properties are yet to be fully understood. The research program I propose in this Discovery grant aims at advancing the knowledge on electronic and ionic transport in eumelanin films as related to their structure. I will adopt a holistic approach, including chemical, structural, redox, electronic and ionic contributions, which I believe it is the ideal platform to study complex natural materials whose behavior is dramatically influenced by external factors (e.g. composition of the atmosphere or presence of salts). The interdisciplinarity of the research will permit to train versatile highly qualified personnel, real "problem solvers" capable of facing the grand challenges of our modern times. My research will generate guidelines to build extended structure-property relationships in melanin and other classes of natural materials for environmentally benign electronics and bioelectronics, e.g. biocompatible and biodegradable supercapacitors for energy storage, chemo- and biosensors, implantable neurological electrodes with improved biocompatibility and will advance the understanding of the functional properties of eumelanin in biological systems.