RETRACTED ARTICLE: Core–shell super-structures via smart deposition of naphthothiadiazole and benzodithiophene-possessing polymer backbones onto carbon nanotubes and photovoltaic applications thereof

Core–shell super-structures were developed via π-stacking of poly[benzodithiophene-bis(decyltetradecyl-thien) naphthothiadiazole] (PBDT-DTNT) and poly[bis(triiso-propylsilylethynyl) benzodithiophene-bis(decyltetradecyl-thien) naphthobisthiadiazole] (PBDT-TIPS-DTNT-DT) as conductive shells onto carbon nanotubes (CNTs). Structure of conjugated polymers substantially determines their deposition model onto CNTs. Regioregular poly(3-hexyl thiophene) (P3HT) chains with hexyl side chains developed delicate nanofibrils with a base attached to CNT surface. However, PBDT-DTNT and PBDT-TIPS-DTNT-DT complicated conductive polymers with fused and infused thiophenic and benzenic rings preferred to be π-stacked with a face-on manner onto CNT surface and fabricate shells. Grafting of CNT surface with a polythiophene such as poly(3-dodecyl thiophene) (PDDT) introduced some defects onto the shell structure; because PBDT-DTNT and PBDT-TIPS-DTNT-DT polymers were not able to be π-deposited onto CNT surface grafted with PDDT. The PDDT grafts were considered as hindrances against the stacking of complicated polymers. The thickness of PBDT-DTNT and PBDT-TIPS-DTNT-DT shells ranged in 10–12 and 5–8 nm, respectively. Higher hindrance of TIPS side structures in PBDT-TIPS-DTNT-DT chains reflected thinner shells. By developing core–shells based on PBDT-TIPS-DTNT-DT and PBDT-DTNT, the conductivity reached 10.11 and 12.15 S/cm, respectively. Donor–acceptor core–shell nano-hybrids were then applied in active layer of photovoltaics. Efficiencies for CNT (core)-PBDT-DTNT (shell) and CNT (core)-PBDT-TIPS-DTNT-DT (shell) were 4.07 and 2.34%, respectively.