Interfacial-Potential-Gradient Induced a Significant Enhancement of Photoelectric Conversion: Thiophene Polyelectrolyte (PTE-BS) and Bipyridine Ruthenium (N3) Cooperative Regulated Biomimetic Nanochannels

Inspired by photosynthesis, the ion transport-based artificial light harvesting system shows unprecedented superiority in photoelectric conversion. However, how to high-efficiently utilize solar energy, just like photosystem I and photosystem II working together in the thylakoid membrane, remains a great challenge. Here, a facile strategy for patterning two photosensitive molecules is demonstrated, that is, thiophene polyelectrolyte (PTE-BS) and bipyridine ruthenium (N3), onto the two segments of symmetric/asymmetric hourglass-shaped alumina nanochannels. Owing to the different energy levels, an interfacial-potential-gradient is established in the tip junction of the nanochannels, wherein photoinduced excited electrons transfer from PTE-BS to N3, resulting in the efficient separation of electron–holes. Simultaneously, the increasing surface-charge-density enhances transmembrane ion transport performance. Thus, the photo-induced ionic current change ratio increases up to 100% to realize a significant photoelectric conversion, which is superior to all of the N3 or PTE-BS individually modified nanochannel systems. By changing the channel geometry from symmetric to asymmetric, the biomimetic nanochannels also exhibit a diode-like ion transport behavior. This work may provide guidance for the development of high-performance photoelectric conversion nanochannel systems.