Green and Economic Transparent Conductive Graphene Electrode for Organic Solar Cell: A Short Review

Abstract

New market trend for organic solar cell (OSC) require lightweight, cost effective, environmentally friendly and flexible. Transparent conductive electrode (TCE) is a main building block in organic solar cell in determining the device performance. Indium tin oxide (ITO) is widely used as transparent conductive material however it has major drawbacks due to relatively expensive, brittle and it limited to use on flexible substrate. This paper provides a short review of the transparent conductive electrode material which required for OSC applications. Issues related with existing TCE material such as ITO is also highlighted. Thus, alternative green material resources which offer low cost, environmentally friendly, mechanically robust and low sheet resistances are strongly required. Graphene is suitable candidate due to their outstanding properties such as good electrical, green material, chemical and thermally stable as well as remarkable mechanical strength and flexibility. The performance of transparent graphene electrode using low cost fabrication method which related with electrical, optical and power conversion efficiency was reviewed. We believed this work will provide beneficial input toward the improvement of OSC device performance.

Fabrication of a Highly Flexible and Affordable Transparent Electrode By Aligned U-Shaped Copper Nanowires Using a New Electrospinning Collector with Convenient Transferability

“…Today, nanotechnology creates much hope for the development of the highly flexible TCEs with superb conductivity and transparency. Among the nanostructured transparent electrodes such as carbon nanotubes, 13−16 carbon nanobuds, 17−20 graphene, 21−28 hybrid structures, 16,17,23,29−33 and metal nanowire meshes, 34−39 the last one due to having suitable features such as high electrical conductivity, low-cost materials, and excellent mechanical properties can be considered as a promising candidate for the production of flexible TCEs. 1,40 However, extensive junction resistance due to the percolation of charges through junctions between different nanowires leads to drop the electrical conductivity of nanowire-based TCEs, which in some cases require thermal processes to reduce the electrical resistance of the junctions that may raise prices of the finished product.…”

“…Today, nanotechnology creates much hope for the development of the highly flexible TCEs with superb conductivity and transparency. Among the nanostructured transparent electrodes such as carbon nanotubes, − carbon nanobuds, − graphene, − hybrid structures, ,,,− and metal nanowire meshes, − the last one due to having suitable features such as high electrical conductivity, low-cost materials, and excellent mechanical properties can be considered as a promising candidate for the production of flexible TCEs. , However, extensive junction resistance due to the percolation of charges through junctions between different nanowires leads to drop the electrical conductivity of nanowire-based TCEs, which in some cases require thermal processes to reduce the electrical resistance of the junctions that may raise prices of the finished product. − Also, an appropriate volume of metal nanowires must be deposited to reach the percolation threshold for achieving high conductivity and maintain good transparency. Basically, in the multistep fabrication method, a metal mesh is constructed on the primary substrate and then transmitted to the final substrate, which in turn causes the failure of some of the metal wires and reduces the efficiency.…”

Carbon‐Based Electrodes for Organic Solar Cells

“…Graphene is an atomically thin two‐dimensional carbonaceous nanomaterial [11] and is regarded the promising alternative to conventional electrodes due to its high conductance, proper work function, solution processibility, and good chemical stability [10] . Graphene‐based materials can be used not only as a bottom electrode but also as a top electrode in OSCs.…”

“…Compared to TCO and metal electrodes, carbon electrodes typically exhibit low cost, solution processibility, high conductivity, and good stability. [10] Carbon-based materials can be produced in mass quantity from low-cost graphite powders, and they can be dispersed in a few solvents, allowing their low-cost solution processibility. Because of their excellent properties, there has been an increase in the number of studies on developing carbon-based electrodes to replace conventional TCO and metal electrodes.…”

“…The structures of graphene, CNT, and graphite are shown in Figure 1A. Compared to TCO and metal electrodes, carbon electrodes typically exhibit low cost, solution processibility, high conductivity, and good stability [10] . Carbon‐based materials can be produced in mass quantity from low‐cost graphite powders, and they can be dispersed in a few solvents, allowing their low‐cost solution processibility.…”