Synthesis of Bi Doped cssnbr3 nanocrystals and investigation of their photocatalytic performance

Abstract

Metal halide perovskites have recently emerged as a promising class of optoelectronic materials; however, the instability issues have impeded their diversified applications. Here we have demonstrated the synthesis of CsSnBr3 (CSB) and 5 mol% Bi-doped CSB (CSB′B) nanocrystals, with a stable cubic perovskite structure following a facile hot injection technique. The successful incorporation of Bi was validated by XRD, XPS, and DRS analyses. Thermogravimetric analysis revealed that Bi-doped CSB exhibited a higher degree of thermal stability than the pristine one. Moreover, Bi substitution in CSB also demonstrated improvement in morphology with a decrement in the size of the nanocrystals from 316±93 to 87±22 nm. A reduction in the optical band gap from 1.89 to 1.73 eV was observed for CSB′B and the PL intensity was quenched due to the introduction of Bi3+ dopants. The photocatalytic properties of the as-synthesized nanocrystals were assessed toward the degradation of rhodamine B dye under both UV-vis and visible irradiation and the results were compared with a widely investigated photocatalyst, P25 nanoparticles. Interestingly, under UV-Vis irradiation, the degradation efficiency of CSB′B is roughly 10% lower than that of P25. However, under only visible irradiation, the same sample exhibited almost five times better performance than the P25. The enhanced photocatalytic activities of CSB′B could be ascribed to the improved morphology, increased optical absorption, the efficient separation of photogenerated charge carriers, etc. Moreover, by employing experimental parameters, DFT based first-principles calculations were performed for a greater understanding of the electronic and optical behavior of the as-synthesized samples, which demonstrated a good qualitative agreement between theoretical and experimental results. The as-synthesized CSB′B sample might be a stable halide perovskite and might have potentiality in visible light driven photocatalysis as well as in other optoelectronic applications.