Department of Electrical and Electronics Engineering, Koc University, Istanbul, Turkey.
Department of Biomedical Sciences and Engineering, Koc University, Istanbul, Turkey.
Sci Rep. 2021 Jan 28;11(1):2460. doi: 10.1038/s41598-021-82081-y.
Capacitive charge transfer at the electrode/electrolyte interface is a biocompatible mechanism for the stimulation of neurons. Although quantum dots showed their potential for photostimulation device architectures, dominant photoelectrochemical charge transfer combined with heavy-metal content in such architectures hinders their safe use. In this study, we demonstrate heavy-metal-free quantum dot-based nano-heterojunction devices that generate capacitive photoresponse. For that, we formed a novel form of nano-heterojunctions using type-II InP/ZnO/ZnS core/shell/shell quantum dot as the donor and a fullerene derivative of PCBM as the electron acceptor. The reduced electron-hole wavefunction overlap of 0.52 due to type-II band alignment of the quantum dot and the passivation of the trap states indicated by the high photoluminescence quantum yield of 70% led to the domination of photoinduced capacitive charge transfer at an optimum donor-acceptor ratio. This study paves the way toward safe and efficient nanoengineered quantum dot-based next-generation photostimulation devices.
电极/电解质界面的电容电荷转移是一种用于刺激神经元的生物兼容机制。尽管量子点在光刺激器件结构中表现出了它们的潜力，但在这种结构中，主导的光电化学电荷转移以及重金属含量阻碍了它们的安全使用。在本研究中，我们展示了基于无重金属量子点的纳米异质结器件，它们可产生电容光响应。为此，我们使用 II 型 InP/ZnO/ZnS 核/壳/壳量子点作为供体，使用富勒烯衍生物 PCBM 作为电子受体，形成了一种新型的纳米异质结。由于量子点的 II 型能带排列和通过高荧光量子产率 70% 来指示的陷阱态的钝化导致电子-空穴波函数重叠减少到 0.52，这导致在最佳供体-受体比下光诱导电容电荷转移占主导地位。这项研究为安全高效的基于纳米工程量子点的下一代光刺激器件铺平了道路。
