First synthesized in 2010, graphdiyne shows potential for application in nanoelectronics and in separation membranes for hydrogen purification.
Graphdiyne is a Graphdiyne is a new 2-dimensional carbon allotrope, consisting of an sp- and sp2-hybridized carbon network and is the subject of increasing research interest due to its promising electronic, optical, and mechanical properties that are distinct from graphene or carbon nanotubes. The interest in carbon allotropes lies in finding simple, inexpensive and readily accessible materials with novel electrical, optical and magnetic properties. Graphdiyne is the first two-dimensional carbon allotrope with sp, sp2, and sp3 three hybridization states, and is predicted to be the most stable of non-natural carbon allotropes. Due to its remarkable electronic structure, graphdiyne is expected to be widely applied in the field of nanoelectronics, semiconductors, solar cells, materials and optoelectronics among others.1
Figure 1: Graphdiyne structure.
Graphdiyne was first synthesized in 2010 by researchers at the Chinese Academy of Sciences. The researchers grew the graphdiyne on a piece of copper foil through a cross-coupling reaction that uses hexaethynylbenzene. The copper foil functions as a catalyst for the cross-coupling reaction and as a substrate for growing graphdiyne.2
Using this approach, the researchers produced graphdiyne films of up to 3.61 cm2 in area. Scanning electron microscopy showed that the films were continuous, uniform and flexible; X-ray photoelectron spectroscopy confirmed that the films were pure carbon; Raman spectroscopy revealed that the films were multilayered; and by atomic force microscopy it was found that the films exhibited excellent semiconducting properties similar to silicon. The team also fabricated a test device, which has a conductivity of 2.516 × 10−4 S m1 at room temperature indicating semiconductor behaviour.
Batteries/Lithium storage
The predicted high capacity and mobility indicate that graphdiyne may offer excellent performance as the anode of lithium batteries. The lithiation potentials (vs Li/Li+) and specific capacities in these materials are found to be enhanced considerably as compared to the conventional graphite-based electrode materials.
Hydrogen storage
Compared to other known membranes, graphdiyne can be used for means of hydrogen purification with the best balance of high selectivity and high permeance. Graphdiyne is atomistically porous – characterized by a regular “nanomesh”- allowing for potential applications as a separation membrane for hydrogen purification. Graphdiyne provides a unique, chemically inert and mechanically stable platform facilitating selective gas separation at nominal pressures using a homogeneous material system, without a need for chemical functionalization or the explicit introduction of molecular pores.
Figure 1: Graphdiyne structure.
Graphdiyne was first synthesized in 2010 by researchers at the Chinese Academy of Sciences. The researchers grew the graphdiyne on a piece of copper foil through a cross-coupling reaction that uses hexaethynylbenzene. The copper foil functions as a catalyst for the cross-coupling reaction and as a substrate for growing graphdiyne.2
Using this approach, the researchers produced graphdiyne films of up to 3.61 cm2 in area. Scanning electron microscopy showed that the films were continuous, uniform and flexible; X-ray photoelectron spectroscopy confirmed that the films were pure carbon; Raman spectroscopy revealed that the films were multilayered; and by atomic force microscopy it was found that the films exhibited excellent semiconducting properties similar to silicon. The team also fabricated a test device, which has a conductivity of 2.516 × 10−4 S m1 at room temperature indicating semiconductor behaviour.
Batteries/Lithium storage
The predicted high capacity and mobility indicate that graphdiyne may offer excellent performance as the anode of lithium batteries. The lithiation potentials (vs Li/Li+) and specific capacities in these materials are found to be enhanced considerably as compared to the conventional graphite-based electrode materials.
Hydrogen storage
Compared to other known membranes, graphdiyne can be used for means of hydrogen purification with the best balance of high selectivity and high permeance. Graphdiyne is atomistically porous – characterized by a regular “nanomesh”- allowing for potential applications as a separation membrane for hydrogen purification. Graphdiyne provides a unique, chemically inert and mechanically stable platform facilitating selective gas separation at nominal pressures using a homogeneous material system, without a need for chemical functionalization or the explicit introduction of molecular pores.
Figure 2: Schematic of graphdiyne hydrogen membrane (Source: RSC Publishing).
Environment
Graphdiyne nanocomposite photocatalysts have been investigated for potential application in air purification and waste water treatment.3
Electronics
Graphdiyne is a semiconductor with a band gap of 0.46 eV. The calculated in-plane intrinsic electron mobility can reach the order of 105 cm2/(V s) at room temperature, while the hole mobility is about an order of magnitude lower. Graphdiyne nanowires show promise as and a novel material in electronic and photoelectric applications. Additionally, graphdiyne nanoribbons have much larger natural “holes” than graphene, thus it is easier to realize doping of various candidates into the “holes” to fabricate n-doping or p-doping one dimensional semiconductor.
Solar cells
It has been demonstrated that the doping of graphdiyne can improve the short circuit current (Jsc) and power conversion efficiency (PCE) of polymer solar cells. A cell with 2.5 wt% graphdiyne exhibits an enhanced Jsc by 2.4 mA/cm2 and the highest PCE (3.52%), which is 56% higher than that of the cell without graphdiyne doping. The improved performance is due to high charge transport capability of graphdiyne and the formation of efficient percolation paths in the active layer.4
Sources:
1. Graphdiyne: a versatile nanomaterial for electronics and hydrogen purification, Chemical Communications Issue 43, 2011.
2. Architecture of Graphdiyne Nanoscale Films, Chemical Communications Issue 19, 2010.
3. A Novel and Highly Efficient Photocatalyst Based on P25-Graphdiyne Nanocomposite, Small. 2011 Nov 29. doi: 10.1002/smll.201101686.
4. The effect of graphdiyne doping on the performance of polymer solar cells, Lancet , vol. 161, no. 19, pp. 2055-2057, 2011.
