Sain, RachanaRoy, AyanKumar, AjayAnuDeekshaKour, PawanpreetSingh, Ravi PratapYadav, Kamlesh2024-01-212024-08-132024-01-212024-08-132023-10-30947839610.1007/s00339-023-07051-9http://10.2.3.109/handle/32116/3784We synthesized Sm2?xDyxO3 (where X = 0.00, 0.03, 0.06, 0.09, and 0.12) nanoparticles using a co-precipitation method and investigated their structural and optical properties. X-ray diffraction (XRD) results reveal that Dy3+-doping in Sm2O3 nanoparticles leads to the formation of a monoclinic polymorphic phase along with the cubic phase of Sm2O3 and its fraction increases with increasing Dy3+-doping concentration. The substitution of Dy3+ at the Sm3+ site converts the cubic Sm2O3 unit cells into distorted monoclinic Sm2?XDyXO3 unit cells. The average crystallite and nanoparticle sizes decrease with increasing Dy3+-doping concentration. Dy3+-ions act as particle size inhibitors, which is attributed to an increase in the segregation of Dy3+-dopant ions at the surface of the nanoparticles with increasing Dy3+-doping content. The peak appearing at 851�cm?1 in the Fourier transform infrared spectroscopy (FTIR) spectra confirms the formation of Sm2O3. Widening of the band gap (Eg) above the band gap of pure cubic Sm2O3 with Dy3+-doping concentration has been observed for X > 0.06, which is due to the Moss-Burstein and quantum size effects. � 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.en-USDoping effectsMoss�Burstein effectOptical propertiesSm₂O₃X-ray methodsArticlehttps://link.springer.com/10.1007/s00339-023-07051-9