The reporter learned from the University of science and technology of China on the 26th that academician Yu Shuhong's team has designed a lattice matched morphological heterojunction photoanode material with near-infrared activity based on narrow-band gap semiconductor materials. The developed heterojunction shows excellent photoelectrochemical hydrogen production performance. Relevant results were published in nature · communication a few days ago.
Direct conversion of solar energy into chemical fuels provides a way to store renewable energy. However, the practical application of Photoelectrochemical hydrogen production is still hindered by its low energy conversion efficiency. At present, more and more semiconductors can be used as photoanode materials. However, these semiconductors generally have a wide band gap, which limits their spectral absorption range to ultraviolet and visible regions. However, infrared light accounts for about 50% of the solar energy. Therefore, extending the spectral absorption range of the material to the infrared region will greatly improve the efficiency of the device.
Narrow band gap semiconductors have near-infrared spectral absorption capacity. However, the electron phonon interaction in narrow band gap semiconductors will shorten the lifetime of photogenerated carriers, which will reduce the concentration of photogenerated holes on the catalyst surface, and then reduce the probability of surface oxidation reaction. So far, it is difficult to improve the photoelectric conversion efficiency (IPCE) of near-infrared active light anode.
The researchers designed a ternary alloy based photoanode with lattice matched morphology heterojunction. The spectral absorption range of the electrode was extended to 1100 nm, and the energy conversion efficiency of Photoelectrochemical hydrogen production was improved. The lattice matched morphology heterojunction reduces the existence of interface defects due to avoiding the influence of lattice mismatch, which is conducive to reducing the recombination rate of photogenerated carriers. Experiments show that the existence of heterojunction improves the separation efficiency of photogenerated carriers and prolongs the lifetime of carriers. Therefore, the material shows excellent performance in IPCE and photocurrent density under near-infrared light.
This study proposes a construction strategy of morphological heterojunction with near-infrared activity. By integrating the advantages of narrow-band gap semiconductors into lattice matched morphological heterojunctions, it provides a new possibility for the design of effective near-infrared active photoelectrochemical devices
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