Influence of Ni doping in a lead-halide and a lead-free halide perovskites for optoelectronic applications

Abstract

Metal halide perovskites have become more popular for applications in solar cells and optoelectronic devices. In this study, the structural, electronic, mechanical, and optical properties of lead and lead-free metal halide cubic perovskites CsPbBr3 and CsGeBr3 and their Ni-doped structures have been studied using the first-principle density functional theory. Ni-doped CsGeBr3 shows enhanced absorbance both in the visible and the ultraviolet region. The absorption edge of Ni-doped CsBBr3 (B = Pb, Ge) shifts toward the lower energy region compared to their undoped structures. Undoped and Ni-doped lead and lead-free halides are found to have a direct bandgap, mechanical stability, and ductility. A combined analysis of the electronic, mechanical, and optical properties of these compounds suggests that lead-free perovskite CsGe0.875Ni0.125Br3 is a more suitable candidate for solar cells and optoelectronic applications.

Effects of Cr- and Mn-alloying on the band gap tuning, and optical and electronic properties of lead-free CsSnBr3perovskites for optoelectronic applications

“…26 The single elastic constant was calculated by using the nite strain theory 27 and the theory employed set homogeneous strains, which were performed on the unit cell to relax the atomic degree of freedom. 12 In the set of the homogeneous strain, there are sixstress components s ij that work in a unit cell under each strain d j . A scissor value of 1.196 was employed during optical properties analysis to diminish the band gap within the theoretical (0.5539 eV) and experimental (1.75 eV) one.…”

“…18 On the other hand, CsSnCl 3 , using metal doping, was reported in the literature and a high absorption and high conductivity were predicted, but the metal-doped samples revealed a high reectivity. In contrast, metal-doped CsGeBr 3 predicted by Islam et al 12 suggested an enhanced band gap nature, but the material reveals a medium absorption and reduced conductivity in the visible region. The symmetry of a supercell is essential to nding the appropriate characteristic, which is not found in the metal-doping band structures available in the literature.…”

“…However, the bulk modulus value is still low compared to the metal-alloyed in the perovskites available in the previously published literature. 12,19 Consequently, the studied Cr-and Mn-alloyed sample considered here is so and exible. Hence, the alloyed materials are promising for making thin lms and more desirable for use in optoelectronic applications.…”

“…As a consequence, several theoretical and experimental investigations have been published in the literature in recent years concerning the replacement of Pb. [11][12][13] The optical properties of the Pb free perovskite material CsSnBr 3 reported by Roknuzzaman et al 11 reveal a medium absorption and reduced conductivity in the visible region. Consequently, CsSnBr 3 is not suitable for practical uses in solar cells and other optoelectronic applications.…”

“…As a consequence of the lack of perovskites to use in optoelectronic applications, several doping effect calculations have been carried out to tune the band gap and enhance the optoelectronic properties. 12,18,19 It has been previously reported that the metal-doped CsGeCl 3 has a Poisson's ratio that lies in a critical position. Therefore, CsGeCl 3 is not considered highly ductile in nature.…”