Li Shengyang, Chen Kexun, Vähänissi Ville, Radevici Ivan, Savin Hele, Oksanen Jani
Engineered Nanosystems Group, School of Science, Aalto University, Tietotie 1, Espoo, 02150, Finland.
Department of Electronics and Nanoengineering, Aalto University, Tietotie 3, Espoo, 02150, Finland.
J Phys Chem Lett. 2022 Jun 23;13(24):5648-5653. doi: 10.1021/acs.jpclett.2c01302. Epub 2022 Jun 16.
Metal-assisted chemical etching (MACE) is a widely applied process for fabricating Si nanostructures. As an electroless process, it does not require a counter electrode, and it is usually considered that only holes in the Si valence band contribute to the process. In this work, a charge carrier collecting p-n junction structure coated with silver nanoparticles is used to demonstrate that also electrons in the conduction band play a fundamental role in MACE, and enable an electroless chemical energy conversion process that was not previously reported. The studied structures generate electricity at a power density of 0.43 mW/cm during MACE. This necessitates reformulating the microscopic electrochemical description of the Si-metal-oxidant nanosystems to separately account for electron and hole injections into the conduction and valence band of Si. Our work provides new insight into the fundamentals of MACE and demonstrates a radically new route to chemical energy conversion by solar cell-inspired devices.
金属辅助化学蚀刻（MACE）是一种广泛应用于制造硅纳米结构的工艺。作为一种无电镀工艺，它不需要对电极，并且通常认为只有硅价带中的空穴对该工艺有贡献。在这项工作中，使用涂有银纳米颗粒的电荷载流子收集p-n结结构来证明导带中的电子在MACE中也起着基本作用，并实现了一种以前未报道过的无电镀化学能量转换过程。所研究的结构在MACE过程中以0.43 mW/cm的功率密度发电。这就需要重新构建硅-金属-氧化剂纳米系统的微观电化学描述，以分别考虑电子和空穴注入到硅的导带和价带中。我们的工作为MACE的基本原理提供了新的见解，并展示了一条受太阳能电池启发的设备进行化学能量转换的全新途径。
