Energy conversion efficiency in the solar cells based on the methylammonium lead halide perovskites: Molecular Approach

In this research, a theoretical investigation of the perovskite-based solar cells (PSCs) was performed to rationalize the the incident photon to current conversion efficiency (IPCE). To achieve this goal, we described photovoltaic processes quantitatively/qualitatively. The ground to excited state transition electric dipole moments (rk,kˊ) and the quantum chemistry reactivity indices such as electrophilicity (ω) of the methylammonium make halide perovskites (MAPbCl3/MAPbBr3: (Fig. 1)) attractive for energy conversion These properties were investigated through density functional theory (DFT), natural bond orbital (NBO) and time-dependent DFT (TD-DFT) at B3LYP/(6-311G++(d,p):for C, H, N) and B3LYP/(6-311G++(d,p): for Pb, Cl, Br) levels of theory [1, 2]. According to the ground state of the studied perovskites, MAPbCl3 has a less tendency of electron donating, which in turn enhances the electron transfer path to be loaded in external circuit. Also, it shows a greater oscillating strength (f) than MAPbBr3, which means a greater probability of charge transfer between the molecular orbitals in the Cl-based perovskite. Also, obtained results show a higher value of rk,kˊ in MAPbCl3 and IPCE in MAPbCl3-based solar cell (Fig. 2). This behavior may be interpreted by an advance in the efficient electron-hole separation in MAPbCl3. Finally, on the basis of different analyses, MAPbCl3 is proposed as a good candidate to be applied in the PSC, in agreement with the previous studies [3, 4].

کلیدواژه ها:

Perovskite ، Solar cell ، Electric dipole moment ، Efficiency ، Excited state