The structural transformation, including the shape and volume of the simulation box, at various temperatures are presented in Figs. . Between 150 K to 125 K, notable changes of box lengths along all three dimensions are observed, particularly a significant contraction in the Z direction, as shown in Fig. . Such contraction is primarily attributed to the organic layer, which exhibits a thickness reduction of 0.49 Å from 150 K to 125 K, as shown in Fig. . This result is close to the experimental measurement by Dahod et al., who reported 0.52 Å contraction in the spacing between the inorganic planes within (BA) 2 (MA)Pb 2 I 7 during its higher to lower symmetry phase transition. In addition, Fig. shows that the simulation box maintains orthogonal shape until 150 K, below which it exhibits significant angular distortions. To more precisely determine the phase transition temperature, we gradually raised the temperature from 125 K to 150 K in 5 K increments after obtaining the The lattice constants and angles predicted from our MD simulations are presented in Temperature which assigns formal charges of +2 and -1 to lead and iodine ions, respectively, and distributes a +1 charge across the atoms of each organic cation. This strategy was adopted for the model transferability among 2D ALHPs with different number of inorganic layers. However, it led to a lower phase transition temperature even in the 3D perovskite. It is noted that the Coulombic interactions, through the formal charges implemented in the current force field, play an important role in the critical phase transition temperature in both 2D and 3D perovskites. Future research is needed to elucidate the fundamental mechanisms governing the influence of these interactions on phase transitions.