Density Functional Theoretical Study of Poly (p-phenylene) anionic derivative intercalated Layered Double Hydroxides composites materials

摘要

Polyanion intercalated layered double hydroxides (LDH) present unique physicochemical characteristics compared with their individual counterparts[1] Poly (p-phenylene)s (PPPs) are an important candidate as light-emitting polymers. In this study, we investigated the Poly(2,5-bis(3-sulfonatopropoxy) -1,4-phenylene,-alt-1,4-phenylene (APPP) intercalated Mg-Al-LDH (APPP/LDH) system by periodic density functional theory (DFT) with Dmo13 module in Material Studio software package. Our calculation shows that the APPP/LDH system is a semiconductor with a direct band gap of 2.534 eV at the Γ point. The valence band (VB) is very close to the Fermi energy level. The band energy around the Fermi levels shows almost completely independence of the k vectors, which implied that the highest valence and lowest conducting bands are localized. The analyses of electronic densities of states (TDOS) conclude that the top of valance band (TVB) and the bottom of conducting band (BCB) are dominated by the 2p(π) and 2p(π*) carbon atomic orbitals of APPP. The 0 2p and Mg/Al 3s orbitals from the LDHs host hydroxides layers contributed the DOS below and above the TVB and BCB, respectively. Therefore, the APPP/MgAlLDHs works as a multiple quantum well structure for confining the valence electrons in the APPP chains, and the intercalated APPPs is dispersion without obvious interchain interaction which is favorable for the optical performance for its solid state devices. This APPPs/LDH composite would find potentials application in the study of novel opto-electronic devices.