In this study, the structural, vibrational, electronic, absorption, transport, optical, molecular electrostatic potential (MEP), and charge transfer properties of pristine cyclo18carbon (C 18 ) and its imide derivatives C 18 -monoimide (CMI), C 18 -diimide (CDI), and C 18 -triimide (CTI) were evaluated using Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD-DFT). The ωB97XD, CAM-B3LYP-D3, HSE, and M062X methods were used with the def2-TZVP basis set. The results show that C 18 -based molecules functionalized with the imide group have low gap energy values, implying that they are useful in electronics. The TD-DFT approach was used for the photophysical analysis of C 18 and its three imide derivatives. It was found that CMI, CDI, and CTI molecules are electron-accepting semiconductors and present a maximum absorption in the near-UV range through TD-CAM-B3LYP-D3 and TD-ωB97XD/def2-TZVP level of theories, which makes them useful in fields such as graphic reproduction, cosmetic tanning, dermatology, and the photo-drying of ink and plastics. The light harvesting emitting (LHE) percentages obtained suggest that these materials can be used as photo-sensitizer in dye sensitized solar cells (DSSC). The pristine C 18 being centrosymmetric, the imide group breaks the symmetry, giving the CMI molecule a polarizability and a first hyperpolarizability values higher than that of the reference molecule (para-nitroaniline), making this CMI molecule a good candidate for linear and nonlinear optics (NLO). According to calculations of charge transfer properties, the dimers of the CMI and CDI molecules have better electron conductivity, while the dimers of the CTI molecule have admirable hole conductivity. The proposed materials can therefore be used in P–N junctions.
Ngui et al. (Sat,) studied this question.