摘要：The fluorescent molecules utilizing hybridized local and charge-transfer (HLCT) state as potential organic light-emitting diodes materials attract extensive attention due to their high exciton utilization. In this work, we have performed the density functional theory method on three HLCT-state molecules to investigate their excited-state potential energy surface (PES). The calculated results indicate the T
1 and T
2 energy gap is quite large, and the T
2 is very close to S
1 in the energy level. The large gap is beneficial for inhibiting the internal conversion between T
1 and T
2, and quite closed S
1 and T
2 energies are favor for activating the T
2 → S
1 reverse intersystem crossing path. However, considering the singlet excited-state PES by twisting the triphenylamine (TPA) or diphenylamine (PA) group, it can be found that the TPA or PA group almost has no influence on T
1 and T
2 energy levels. However, the plots of S
1 PES display two kinds of results that the S
1 emissive state is dominated by charge-transfer (CT) or HLCT state. The CT emission state formation would decrease the S
1 energy level, enlarge the S
1 and T
2 gap, and impair the triplet exciton utilization. Therefore, understanding the relationship between the S
1 PES and molecular structures is important for designing high-performance luminescent materials utilizing HLCT state.
