Top-down Strategy toward Versatile Graphene Quantum Dots for Organic/Inorganic Hybrid Solar Cells

Abstract

Metal oxide nanocrystals have been pursued for various applications in photovoltaics as a buffer layer. However, it remains a challenging task to adjust their energy levels to achieve a better match of the donor–acceptor system. Herein, we report the fabrication of graphene quantum dots (GQDs) with bright blue photoluminescence by a top-down strategy based on laser fragmentation with posthydrothermal treatment. The GQDs demonstrate appropriate energy level positions and are used as an intermediate buffer layer between TiO2 and P3HT to form a cascade energy level architecture. The introduction of the GQDs into a bulk heterojunction hybrid solar cell has led to an enhancement of the power conversion efficiency.

2D–Materials‐Based Quantum Dots: Gateway Towards Next‐Generation Optical Devices

“…Hydrothermal synthesis. A,B) GQDs: SEM micrograph of (A) raw GQDs, B) HRTEM image of single GQDs, Reproduced with permission . Copyright 2015, American Chemical Society.…”

“…Low reaction temperature favors the amine functionalization and high temperature (>120 °C) cause dissociation of primary amine due to nucleophilic reactions thereby lowering the C/N ratio . A different approach that combined laser fragmentation and post‐hydrothermal treatment to attain bright blue PL GQDs was realized in incorporating into heterojunction hybrid solar cell to improve power conversion efficiency . Figure A,B shows the scanning electron microscopy (SEM) and HRTEM images of GQDs.…”

Colloidal quantum dots suitability for long term cell imaging

“…To qualify as probes for in vitro diagnostics, QDs must be biocompatible. This condition may be achieved, both for bottom-up [11][12][13] and top-down [14][15][16] prepared QDs, by modifying their surface via the controlled addition of layers of organic polyelectrolytes, peptides and/or other biomolecules, such as mono or polyclonal antibodies [17]. Previous work [18] have reported the use of non-polar quantum dots, rendered biocompatible by means of DHLA (dihydrolipoic acid) coverage, to investigate cell uptake/endocytic routes, and conjugated to avidin in order to interact with biotinylated cell surface.…”

Enhanced Conversion Efficiency of III–V Triple-junction Solar Cells with Graphene Quantum Dots

“…GQDs have been extensively exploited due to their peculiar properties such as low toxicity, strong fluorescence, high surface area, large solubility, and tunable band gaps78910. Recently, GQDs have shown great promise in organic or organic-inorganic hybrid photovoltaic applications789. GQDs have been used as electron acceptors in a P3HT-based solar cell, wherein GQDs improve the electron transport in the active layer and the device achieve a 1.28% conversion efficiency9.…”

“…GQDs have been used as electron acceptors in a P3HT-based solar cell, wherein GQDs improve the electron transport in the active layer and the device achieve a 1.28% conversion efficiency9. GQDs have also been used as an intermediate buffer layer to form a cascade alignment of energy levels in organic-inorganic hybrid solar cells, facilitating the charge carrier transport and increasing the cell efficiency78. In addition, a combination of GQDs and ZnO nanowires have been demonstrated as a solar harvesting material in solid-state solar cells10.…”