The initial simulation results, presented in A closer examination of the band diagram in Figure (c) provides insight into the underlying reasons for this performance limitation. Large conduction band offsets (CBO) and valence band offsets (VBO) are observed at the interfaces between the electron transport material (ETM), the absorber layer, and the hole transport material (HTM). These offsets create potential energy barriers that hinder the flow of charge carriers, leading to increased recombination losses at the interfaces , . The reduced charge collection efficiency due to these interfacial barriers directly contributes to the lower overall device performance.