Designing the Interface of Carbon Nanotube/Biomaterials for High-Performance Ultra-Broadband Photodetection

Inorganic/biomolecule nanohybrids can combine superior electronic and optical properties of inorganic nanostructures and biomolecules for optoelectronics with performance far surpassing that achievable in conventional materials. The key toward a high-performance inorganic/biomolecule nanohybrid is to design their interface based on the electronic structures of the constituents. A major challenge is the lack of knowledge of most biomolecules due to their complex structures and composition. Here, we first calculated the electronic structure and optical properties of one of the cytochrome c (Cyt c) macromolecules (PDB ID: 1HRC) using ab initio OLCAO method, which was followed by experimental confirmation using ultraviolet photoemission spectroscopy. For the first time, the highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels of Cyt c, a well-known electron transport chain in biological systems, were obtained. On the basis of the result, pairing the Cyt c with semiconductor single-wall carbon nanotubes (s-SWCNT) was predicted to have a favorable band alignment and built-in electrical field for exciton dissociation and charge transfer across the s-SWCNT/Cyt c heterojunction interface. Excitingly, photodetectors based on the s-SWCNT/Cyt c heterojunction nanohybrids demonstrated extraordinary ultra-broadband (visible light to infrared) responsivity (46–188 A W^–1) and figure-of-merit detectivity <i>D</i>* (1–6 × 10¹⁰ cm Hz^1/2 W^–1). Moreover, these devices can be fabricated on transparent flexible substrates by a low-lost nonvacuum method and are stable in air. These results suggest that the s-SWCNT/biomolecule nanohybrids may be promising for the development of CNT-based ultra-broadband photodetectors

Ultrahigh Thermal Conductivity of Assembled Aligned Multilayer Graphene/Epoxy Composite

The exceptional thermal conductivity of graphene is expected to endow polymer composites with ultrahigh thermal conductivities, which can be even similar to those of some metals such as stainless steel and aluminum alloy. The thermal conductivities of composites prepared by dispersing multilayer graphene (MLG) in epoxy matrix increase only by an order of magnitude over the pure epoxy. However, the improvement has been limited since the large interfacial thermal resistance exists between graphene and the surrounding epoxy. We have reported an extraordinary increase in thermal conductivity of the MLG/epoxy composites through the fabrication of the vertically aligned and densely packed MLG in the epoxy matrix. The ultrahigh thermal conductivity of 33.54 W/(m K) has been achieved in the aligned MLG/epoxy composite (AG/E). The thermal conductivity of AG/E exhibits a positive temperature response related to the aligned structure while increasing the temperature from 40 °C to 90 °C