The effect of the spinning speed variation on the perovskite solar cell efficiency
Mohammed S. Mehde, Abdulnasser M. Al-Gebori, Ali K. Al-Mousoi
Abstract
Abstract In this work, compact titanitum dioxide (c-TiO 2 ), amorphous titanitum dioxide (mp-TiO 2 ) and methylammonium lead iodide (CH 3 NH 3 PbI 3 ) films were prepared by spin coating method under different different rotational speed of the CH 3 NH 3 PbI 3 films. Many characterization measurements were achieved on the deposited CH 3 NH 3 PbI 3 films in order to study the change that resulted from different parameters. The X-ray diffraction (XRD) measurements revealed that the lattice constants of the fabricated CH 3 NH 3 PbI 3 films were close to the slandered values. The atomic force microscopy (AFM) measurements were conducted in order to study the morphology of the fabricated CH 3 NH 3 PbI 3 films at different scale, these results displayed that the grain size of the CH 3 NH 3 PbI 3 films in the range between about 160nm to 210 nm. The field emiision scanning electron microscopy (FE-SEM) results of the fabricated CH 3 NH 3 PbI 3 films were well agreed to the AFM result especially in the grains shape and distribution. Transmittance measurements have been done to determine the variation of the energy gap and absorption coefficient the CH 3 NH 3 PbI 3 films. The structure form of the perovskite solar cells were FTO/c-TiO 2 /mp- TiO 2 /CH 3 NH 3 PbI 3 /Au, the C-V measurements were achieved to determine the built-in potential, which found to have the highest value when using 4000 rpm during the synthesis of the perovskite layer. In addition, the I-V measurements in dark conditions have been conducted to compute the ideality factor and the saturation current, which are considered important parameters that influences the characteristics of the solar cells. The best solar cell efficiency was obtained at spinning speed of 4000 rpm.