Light-Driven Ion Transport through Single-Heterojunction Nanopores

Abstract

Inspired by natural photosynthesis, light has become an emerging ionic behavior regulator and ion-pumping source. Nanoprocessing technology has allowed the bridge between the light-regulated nanofluids and the optoelectronic properties of two-dimensional (2D) materials, which inspires applications like energy harvesting and enhances fundamental understandings in nanofluidics. However, unlike light-induced ion pumping based on densely layered membranes with multiple nanochannels, experimental implementation on atomically thin materials featuring only a single nanochannel remains challenging. Here, we report light-induced ion pumping based on a single artificial heterojunction nanopore. Under light illumination, the induced current through a single nanopore reaches tens of picoamperes. The hole–electron separation originating from the optoelectrical property of a van der Waals PN junction is proposed to capture the light-driven ion transport. Further, different methods are adopted to modify the ion behavior and response time, presenting potential applications in fluidic photoenergy harvesting, photoelectric ion transport control, and bionic artificial neurons.

Bioinspired 2D nanofluidic membranes for energy applications

“…In the past few years, nanofluidic photoelectric conversion has received increasing research attention. [241][242][243][244] In general, there are two approaches for nanofluidic photoelectric conversion and the first approach involves the use of light-responsive molecules. For example, Wen et al added light-responsive photoacid molecules into solutions.…”

Soft Nanofluidic Machinery

“…The generation of the Coulomb drag current is determined by the electronic and phononic structures of the substrate and dielectric responses of the liquid, showing the potential of quantum engineering in nanofluidic energy conversion. Mechano- or photosensitive nanochannels that convert mechanical or light energy into directional transport of protons and ions can also be developed to mimic the processes and functions of the human somatosensory network and photosynthesis systems, respectively. , However, the energy conversion efficiency of these setups is still low and may only find applications of (self-)­powering with low energy demand. The mechanisms of these energy conversion processes should be better understood to promote their performance.…”

Local Electric Potential-Driven Nanofluidic Ion Transport for Ultrasensitive Biochemical Sensing

“…For example, channelrhodopsins (ChRs), which are widely used for optical control of neurons and have single-molecule sensitivity, , selectively generate photoinduced proton, sodium, or chloride influx by adsorbing and converting sunlight energy into the membrane potential (Figure B). Inspired by these biological nanofluidic devices, a group of researchers have developed biomimetic nanofluidic devices by virtue of semiconductor nanomaterials as building units for applications in ion pumps, − osmotic energy harvesting, , ion gating, , and optical detectors . The key mechanism in these devices is based on optoelectronic effect-induced local membrane potential, which originates from the separation and directional movement of photogenerated electrons and holes in the nanofluidic membrane under light illumination. , Self-powered photoelectrochemical biosensors have also demonstrated the advantages of local potential; − however, experimental investigations are yet unfulfilled for nanofluidic biosensors.…”