Strain-Induced Band-Edge Modulation in Lead-Free Antimony-Based Double Perovskite for Visible-Light Absorption

Herein, we synthesized Sb-based single crystals (SCs) of Cs2AgSbCl6 with an impressive low bandgap of similar to 1.82 eV and demonstrated the effect of strain on optical properties. Interestingly, the polycrystalline ground powder and the heated SCs of Cs2AgSbCl6 exhibited a larger bandgap of similar to 2.55 eV. The reduction of bandgap is attributed to the existence of strain in the SC as confirmed by X-ray diffraction and Raman spectroscopy and supported by density functional theory (DFT) calculations. The strain engineering for bandgap reduction can play a pivotal role for developing low-bandgap lead-free double perovskite for environmentally friendly solar cell applications.

Automated summary

In this study, we synthesized Sb-based single crystals of Cs2AgSbCl6 with a low bandgap of approximately 1.82 eV and investigated the effect of strain on their optical properties. Interestingly, the polycrystalline ground powder and heated single crystals showed a larger bandgap of about 2.55 eV. The reduction in bandgap is attributed to the presence of strain in the single crystals, which was confirmed by X-ray diffraction and Raman spectroscopy and supported by density functional theory calculations. Strain engineering for bandgap reduction could be crucial for the development of environmentally friendly solar cells with low bandgaps.