The capability of SnTe QDs as QDSCs working in the visible–NIR region and the effects of Eu-doping on improvement of solar cell parameters

The current work is the first effort to show the capability of SnTe quantum dots (QDs) in as a quantum dots solar cell device, which work in visible-near-infrared (NIR) regions, and improvement of the solar cell parameters by Eu-doping. Undoped and Eu-doped SnTe QDs with different Eu concentration from 2 to 6% were synthesized by a co-precipitation method. X-ray diffraction patterns and transmission electron microscopy images indicated that, crystallite and particle size of the samples were decreased by increasing of Eu content. Fourier-transform infrared (FTIR) and Raman spectroscopy results revealed that some vibration modes were appeared and disappeared by Eu-doping. According to the photoluminescence (PL) results, PL intensity of the doped sample was enhanced significantly in the green region in comparison to the PL intensity of the undoped sample. Ultraviolet-visible-near infrared spectroscopy results indicated that the pristine and Eu(2%)-doped samples don’t have any absorption in the visible region, while, Eu(4% and 6%)-doped SnTe QDs showed a good absorption in this region. Photocurrent measurements showed that, unlike the pristine and Eu(2%)-doped QDs, Eu(4% and 6%)-doped SnTe QDs showed a high responsivity in the visible and NIR regions. Solar cell measurements showed that, solar cell parameters such as short current density (J_sc), open circuit voltage (V_oc), conversion efficiency values (η), and fill factor (FF) were increased by Eu-doping.