PbI₂ band gap engineering by gel incorporation

Incorporation of guest materials into semiconducting single crystalline hosts leads to the formation of semiconducting single-crystal composites. However, limited efforts have been made to comprehensively investigate the property of these potential functionalized single-crystal composites. Herein, PbI₂/gel single-crystal composites have been successfully prepared. Diffuse reflectance spectra show a clear increase in the band gap of PbI₂ after gel incorporation. The band gap is further increased through expanding the area of host/guest interfaces or enhancing the interatomic forces at the interfaces. The interatomic forces (electrostatic interaction) at the host/guest interfaces are attributed to this band gap shift. As such, this study provides a novel and facile way for band gap engineering by gel incorporation.