Send Orders for Reprints to reprints@benthamscience.net Current Nanoscience, 2022, 18, 655-658 655 PERSPECTIVE 1573-4137/22 $65.00+.00 © 2022 Bentham Science Publishers Nanostructured Hybrid Materials based on Semiconductor Quantum Dots and Graphene, Graphene Oxide, or Reduced Graphene Oxide Domingo I. Garcia-Gutierrez 1,2,* 1 Universidad Autónoma de Nuevo León, UANL, Facultad de Ingeniería Mecánica y Eléctrica, FIME, Av. Universidad S/N, Cd. Universitaria, San Nicolás de los Garza, Nuevo León, C.P. 66450, México; 2 Universidad Autónoma de Nuevo León, UANL, Centro de Innovación, Investigación y Desarrollo en Ingeniería y Tecnología, CIIDIT, Apodaca, Nuevo León, C.P. 66628, México Abstract: Nanostructured hybrid materials (NHMs) based on nanostructures, such as graphene or graphene-related materials and semiconductor quantum dots (QDs) or nanoparticles, have attracted a great deal of attention from the scientific community in the last decade. Their potential applications range from more conventional optoelectronic uses (e.g., photodetectors and solar cells), passing through the field of photocatalysis and spanning to the biotechnology arena, as they have been used in bioimaging applications. In this perspective paper, a summary of the developments achieved in this type of NHM is presented, along with an outlook on the main challenges that are still needed to be overcome. A R T I C L E H I S T O R Y Received: August 31, 2021 Revised: October 13, 2021 Accepted: November 12, 2021 DOI: 10.2174/1573413718666220119103724 1. INTRODUCTION Hybrid materials are of great importance due to the independent properties displayed by their components. Several attempts have been made to reach a synergistic symbiosis where the novel resulting hybrid material shows enhanced properties because of the optimized and combined properties of the component materials. In the area of optoelectronic applications, hybrid materi- als based on graphene and semiconductor QDs have been explored diligently by several research groups in recent years. Semi- conductor QDs are known for exhibiting very interesting optical properties, especially the tunability displayed by their energy bandgap (E g ) and the multiple exciton generation phenomena, both related to quantum confinement effects, which are size- dependent in nature [1, 2]. Both effects make them very attractive candidates for diverse optoelectronic applications. Addition- ally, the energy level modification through capping ligand variation, reported for many semiconductor QDs [3-5], has opened an additional path to manipulate their optoelectronic properties, increasing the interest within the scientific community. On the other hand, the excellent charge carrier transport properties displayed by graphene (e.g., electron mobility ~200,000 cm 2 V -1 s -1 ) [6], among many other advantageous properties, make it a very attractive material for optoelectronic applications, thus increas- ing the desire to use it in combination with semiconductor QDs to create hybrid materials with excellent and tunable optical properties and remarkable charge carrier transport properties. 2. GRAPHENE-SEMICONDUCTOR QDs BASED NHMs Among the first reports found in the literature regarding this type of NHMs, the following can be highlighted. Guo et al. [7] reported the fabrication of a layer-by-layer hybrid material based on the alternation of graphene and semiconductor QDs layers. In their work, they alternatively placed the layers of chemically reduced graphene and layers of CdS QDs and observed im- proved performance with higher internal power conversion efficiency (IPCE = ~16%) and a higher measured photoresponse (~1.08 mA cm -2 ) compared to a similar hybrid material based on single-walled carbon nanotubes (SWCNT) and CdS QDs. These improvements were attributed to an enhanced energy band alignment between CdS QDs and graphene, over the SWCNT, producing a more favorable charge carrier separation at the interface between the materials composing the NHMs and an improved charge carrier transport in the graphene phase. Konstantatos et al. [8] developed a photodetector (PD) based on a hybrid material composed of a single or a bilayer of graphene and a PbS QDs thin film. They reported the excellent perfor- mance of the PD device based on this hybrid material, demonstrating a gain as high as ~10 8 electrons per photon, a responsivity of ~ 10 7 AW -1, and a detectivity of ~7 x 10 13 Jones. They attributed these excellent results to several factors, such as the strong and tunable optical absorption displayed by the PbS QDs, producing electron-hole pairs that are separated at the interface *Address correspondence to this author at the Universidad Autónoma de Nuevo León, UANL, Facultad de Ingeniería Mecánica y Eléctrica, FIME, Av. Univer- sidad S/N, Cd. Universitaria, San Nicolás de los Garza, Nuevo León, C.P. 66450, México; Universidad Autónoma de Nuevo León, UANL, Centro de Innova- ción, Investigación y Desarrollo en Ingeniería y Tecnología, CIIDIT, Apodaca, Nuevo León, C.P. 66628, México; E-mail: domingo.garciagt@uanl.edu.mx