Rashba Splitting in Two Dimensional Hybrid Perovskite Materials for High Efficient Solar and Heat Energy Harvesting

Abstract

The physical properties of two-dimensional (2D) lead halide based hybrid perovskites are quite exciting and challenging. Further, the role of organic cations in 2D perovskites is still in a debate. We investigated layered (CH 3 (CH 2 ) 3 NH 3 ) 2 (CH 3 NH 3 )Pb 2 I 7 2D Ruddlesden−Popper (2DRP) phase (M1) and 2D derivative of CH 3 NH 3 PbI 3 (M2) using density functional theory. The spin orbit coupling mediates the significantly large Rashba splitting energy of 328.5 meV for M2, which is higher than earlier 2D hybrid perovskites. At the picosecond time scale, the dynamical Rashba effect was observed due to organic and inorganic cation dynamics. Two step absorption suggests an indirect optical gap of 2.38 and 2.15 eV for M1 and M2, respectively and solar performance depicts excellent power conversion efficiency of 14.92% and 19.75% for M1 and M2, respectively. For the first time, we explored the thermoelectric properties of 2D hybrid perovskites and perceived high power factor for p-type doping in M2. Our findings suggest that these novel 2D perovskites have the potential to be used in solar and heat energy harvesting.

Mobility driven thermoelectric and optical properties of two-dimensional halide-based hybrid perovskites: impact of organic cation rotation

“…The maximum splitting strength is observed for the A2 structure, which is even higher than the previously reported ground state structure. 41 Moreover, the calculated Rashba splitting strength is lower than the earlier reported 3D and 2DRP phases of perovskites. [38][39][40] Furthermore, the strength parameter a R varies between 0.047 to 0.278 through the MA cation rotation, which suggests that the rotation of the MA cation significantly tunes the spin-dependent properties on 2D perovskites.…”

“…The energy splitting and momentum offset in k-space are tabulated in Table 2 for the VBM only as the Rashba splitting is forbidden under the SOC effects for the case of the CBM in the whole set of rotations. The parameter a R determines the strength of Rahsba splitting, 1,41,53,58 which is presented in Table 2 along with the splitting energy and momentum offset. The maximum splitting strength is observed for the A2 structure, which is even higher than the previously reported ground state structure.…”

“…[34][35][36] The complex and diverse structure of 2DRP perovskites gives rise to Rashba splitting due to the strong spin-orbit coupling (SOC) effects and breaking of the inversion symmetry. [37][38][39][40][41] In our previous work, two structures of 2D halide-based hybrid perovskites (i) layered (BA) 2 (CH 3 NH 3 ) Pb 2 I 7 (M1) and (ii) 2D derivative of 3D CH 3 NH 3 PbI 3 (M2) was investigated using DFT calculations along with the SOC effects, where the significantly large value of Rashba splitting energy was obtained. 41 Moreover, Motta et al suggested that the organic cation rotation plays an important role in the electronic and optical properties of bulk CH 3 NH 3 PbI 3 .…”

“…[37][38][39][40][41] In our previous work, two structures of 2D halide-based hybrid perovskites (i) layered (BA) 2 (CH 3 NH 3 ) Pb 2 I 7 (M1) and (ii) 2D derivative of 3D CH 3 NH 3 PbI 3 (M2) was investigated using DFT calculations along with the SOC effects, where the significantly large value of Rashba splitting energy was obtained. 41 Moreover, Motta et al suggested that the organic cation rotation plays an important role in the electronic and optical properties of bulk CH 3 NH 3 PbI 3 . 25 However, the orientation of organic cation (MA = CH 3 NH 3 + ) in the 2DRP phase of perovskite is still unexplored and needs to be revealed as it significantly roots the hydrogen bond interactions between organic and inorganic parts of the structure.…”

Metal Halide Perovskites as Emerging Thermoelectric Materials

“…Some other lead-free MHPs were also predicted to have promising TE properties, such as CsTmCl 3 , as well as the chalcogenide perovskite-like analogue BaZrS 3 . Furthermore, low-dimensional quasi-2D RP perovskites may be promising for TE applications due to the potential for high power factors as well as their exceptionally low thermal conductivity. , These perovskites can be viewed as natural superlattices, while it is well known that superlattices may yield an improved TE performance. , Nanostructuring is yet another well-known approach for the enhancement of TE performance in general, but studies of the TE properties of MHP nanostructures have been scarce so far.…”