Graphene Quantum Dot-Based Organic Solar Cells

Abstract

Current research in organic photovoltaic (OPV) is largely focused on the development of low cost OPV materials such as semiconductor quantum dots (QDs). Graphene quantum dots (GQDs) are a fascinating class of QDs having size below 10 nm. They have emerged as an alternative to semiconductor QDs in photovoltaics due to their size-dependent photoluminescence (PL) and tunable band gap properties. They are expected to be a versatile candidate due to their low cost, non-toxicity, and biocompatibility. Recently, it has been shown that they are promising for efficient light harvesting in solar cells. Keeping this in view, we present a comprehensive review of the progress made so far for the application of GQDs in organic solar cells. IntroductionGraphene is a two-dimensional sheet of sp 2 -hybridized carbon. Its extended honeycomb network can be stacked to form a 3D graphite, 1D nanotube, and 0D fullerenes. Discovered by Novoselov and his group in 2004 [1], it is considered to be one of the most promising materials for the future nanotechnology owing to its low cost coupled with the superior electronic, thermal, and mechanical properties as well as an enhanced chemical stability. The most exciting characteristics are ambipolar field effect [1], the quantum Hall effect [2][3][4][5][6][7], and extremely high carrier mobility [8][9][10][11] that can find several applications including in optoelectronic devices. The use of graphene sheets (GSs) in the solar cell devices is possible due to the efficient charge transfer in graphene. However, the zero band gap in graphene imposes limitations for optoelectronic applications, since a finite band gap is