Towards bioelectronics: Charge carrier transport properties and structure of eumelanin thin films

黑色素，可以在许多植物，动物，人类皮肤，头发，眼睛和大脑中找到，具有类似于半导体的特性。它强烈吸收可见光和紫外线，使其能够保护我们的身体免受阳光照射。它也传导电荷，而它的电导率强烈依赖于湿度和温度。仍然没有很好地理解哪种类型的电荷载体，离子或电子，被传输以及潜在的机制是什么。我们将制造第一个黑色素场效应晶体管来解决这些问题。这种配置将使我们能够确定占主导地位的电荷载流子，并详细描述黑色素薄膜的电特性。此外，黑色素膜的生长和结构将在纳米尺度上进行研究，以将电学性质与黑色素分子的组织联系起来，这是文献中另一个有争议的问题。黑色素的半导体特性结合其稳定性和生物学性质，使其在紫外线保护膜，化学传感器和太阳能电池等应用中非常有趣。更好地了解黑色素的物理特性将为这些应用铺平道路。对黑色素等功能性生物分子的研究有可能产生环境友好的、可生物降解的技术和与人体环境相容的医疗器械。

The pigment melanin, which can be found in many plants, animals, human skin, hair, eyes, and brain, has properties similar to a semiconductor. It absorbs strongly visible and UV light, enabling it to protect our body from sunlight. It also conducts charges, whereas its conductivity depends strongly on humidity and temperature. It is still not well understood which type of charge carriers, ions or electrons, is transported and what is the underlying mechanism. We will fabricate the first melanin field-effect transistors to address these questions. This configuration will allow us to determine the dominating charge carriers and to characterize the electrical properties of melanin thin films in detail. Additionally, the growth and structure of melanin films will be studied on a nanometer scale to relate electrical properties to the organization of melanin molecules, another issue disputed in literature. Melanin's semiconducting properties combined with its stability and biological nature make it very interesting for applications like UV-protective films, chemical sensors and solar cells. A better understanding of melanin's physical properties will pave the way for these applications. Research on functional biomolecules like melanin has the potential to result in environmentally friendly, bio-degradable technology and medical devices compatible with the environment of human body.