Iranian Nanotechnology Society International Journal of Nanoscience and Nanotechnology 1735-7004 21 3 2025 09 30 Solvothermal Synthesis and Characterization of CsPbI3, CsSnI3 and CsPb1-xSnxI3 Perovskite Nanocrystals 137 148 738628 10.22034/ijnn.2026.2068417.2695 EN Hari Ganesha Y Department of Studies in Physics, Mangalore University, Mangalagangothri – 574 199, India 0009-0005-6548-5381 Ramaraja Varma V Microtron Centre, Department of Studies in Physics, Mangalore University, Mangalagangothri – 574 199, India 0000-0002-4946-5787 Gopalakrishna Naik K Department of Studies in Physics, Mangalore University, Mangalagangothri – 574 199, India 0000-0002-9212-4320 Journal Article 2025 08 11 The solvothermal method synthesized CsPbI3, CsSnI3, and CsPb1-xSnxI3 perovskite nanoparticles. The powder X-ray diffraction (XRD) patterns of the synthesized CsPbI3 and CsSnI3 were found to be -CsPbI3 and black -CsSnI3 perovskite phases, respectively. The nanoparticles synthesized from equal molar masses of Pb and Sn indicate the formation of -CsPbI3, black -CsPbI3, and black -CsSnI3 perovskite phases instead of the formation of the intended quaternary CsPb0.5Sn0.5I3 solid solution. The field emission scanning electron microscopy (FESEM) images show the formation of nanorods for CsPbI3, nanorods and nanoplatelets for CsSnI3, and nanorods/nanowires and nanoplatelets for the intended CsPb0.5Sn0.5I3 nanostructures. The Fourier transform infrared (FTIR) spectra of the synthesized samples show the presence of the oleic acid surfactant in the synthesized nanostructures. The estimated band gaps of the synthesized -CsPbI3 and B--CsSnI3 nanostructures from the UV-visible optical absorption measurements were found to be slightly higher than the reported bulk band gap values of these materials, which may be due to the quantum confinement effect. The exciton-related absorptions were observed both in -CsPbI3 and B--CsSnI3 nanostructures. The band gaps of both -CsPbI3 and B--CsSnI3 nanostructures were found to show a blue shift with aging of the nanostructures, which may be due to the predominance of the band-to-band absorption over the excitonic absorption with aging of the nanostructures. The synthesized nanostructures appear to exhibit long-term structural stability, as confirmed by the observation of stable XRD patterns and UV-visible optical absorption spectra of the synthesized samples, which were maintained for four to six months after synthesis https://www.ijnnonline.net/article_738628_e880dcdb1759697230b8ade78c5a4980.pdf