Efficient separation and low thermalization of hot carriers in natural superlattice of BiOCuCh (Ch = S, Se, Te)

The optic-electronic response is usually limited by poor electron-hole separation and phonon thermalization. Here, we show that natural superlattice materials with charged layers in BiOCuCh (Ch = S, Se, Te) can effectively suppress bulk carrier recombination and dissipation from phonon. The photogenerated hot carriers in BiOCuCh are separated by the intrinsic p-n junction naturally composed of the [Cu(2)Ch(2)](2-) and [Bi2O2](2+) layers, and transport occurs with high speed within the two layers. Moreover, its dissipation can be substantially reduced because the interlayer coupling leads to low phonon thermalization. As a result, these materials both show prominent response to full-spectrum solar lights and resemble cocatalysts in their characteristics. Because of these merits, these oxychalcogenides provide a penetration point up-and-coming platform for the exploration of materials with an extraordinary optoelectric response.

Automated summary

We demonstrate that BiOCuCh materials with charged layers can effectively suppress carrier recombination and phonon dissipation. The photogenerated hot carriers are separated by the intrinsic p-n junction and transport at high speed within the two layers. Additionally, interlayer coupling leads to reduced phonon thermalization. As a result, these oxychalcogenides show a significant response to full-spectrum solar light and exhibit cocatalyst-like characteristics. These materials provide a promising platform for exploring materials with extraordinary optoelectric response.