Influence of zinc concentration on the structural, morphological and optical properties of zinc doped Lead iodide for optoelectronic and photovoltaic applications

We investigate the influence of Zinc (Zn) proportion on the structural, morphological and optical properties of Zinc doped Lead iodide (Zn–PbI 2 ). The doped precursors were synthesed by adding varying amount of Zinc acetate to Lead iodide from 2 % to 6 %. The X-ray diffraction analysis shows that the peaks positions slightly shifted towards high 2theta for Zn–PbI 2 . The film surfaces were improved with Zn incorporation and the thickness slight increases from 472.440 nm for PbI 2 –474.445 nm for 4 % Zn–PbI 2 . A noticeable decrease in the ratio of Pb–Zn from 2.7:1 for PbI 2 to 2.2:1 for the 4 % doped sample was observed. The lowest value (22.494 nm) of the root mean square roughness was observed in the 4 % doped sample. It was observed that the doped samples exhibit a blue shift in the major peaks of the photoluminescence intensity from 524 nm for PbI 2 to 519 nm. The energy gap was observed to decrease from 2.63 eV for 0 % Zn–PbI 2 –2.42 eV 4 % Zn–PbI 2 sample. The absorbance, reflectance, extinction coefficient and imaginary part of dielectric constant were found to have their peak intensities when 4 % Zn was added to PbI 2 .While transmittance, refractive index and real part of dielectric constant were found to have their least intensities when 4 % Zn was added. The 4 % doped sample was observed to be the most suitable material for optoelectronic and photovoltaic applications due to its outstanding properties.