Advancement in the properties of novel NPB derivatives for highly efficient organic solar cell of PCE-19.53%

Five completely new molecules (NPB1-NPB5) of NPB core unit have been theoretically investigated using the DFT method B3LYP and (6-31) G (d, p) basis set. Electrical, geometrical, and photo-physical characteristics of the NPB and its derivatives were studied. The studies showed that NPB1 has the appropriate smaller band gap (2.08 eV) among other studied molecules. The introduced conjugated system in the synthesized NPB at the axial position has caused a red shift in the absorption spectrum and boosted molecular stability. Additionally, the enhanced self-assembly of NPB derivatives has improved their dipole moment (NPB – and range of all derivatives – 5.29 eV–8.97 eV), resulting in a greater consistency at the donor and acceptor interface which increased the FF (NPB – 86.87 and its new derivatives have FF values from 89.97 to 91.17). The behavioral activity of efficient charge mobility was examined because electrons require less energy to reorganize than holes do. All of the molecules emerged as being acceptable for the phenomenon of electron transport. A comparative study of reorganization energy has revealed that NPB4 – ʎe = 0.001927 eV has an effective capacity to transfer charges. PCBM (acceptor) interaction with designed molecules was examined. Comparatively, the NPB3 has Voc – 1.23 eV, which is noticeably better than R (0.86). The above-mentioned values of model donor moieties have proved them as an appropriate donor resource. According to this study, NPB derivatives are suggested for organic-based solar cells with improved efficiency.