Graphene Nanoplatelets Doped with N at its Edges as Metal‐Free Cathodes for Organic Dye‐Sensitized Solar Cells

Abstract

Challenging precious Pt-based electrocatalysts for dye-sensitized solar cells (DSSCs), graphene nanoplatelets that are N-doped at the edges (NGnPs) are prepared via simply ball-milling graphite in the presence of nitrogen gas. DSSCs based on specific nanoplatelets designated "NGnP5" display superior photovoltaic performance (power conversion efficiency, 10.27%) compared to that of conventional Pt-based devices (9.96%). More importantly, the NGnP counter electrode exhibits outstanding electrochemical stability and electrocatalytic activity with a cobalt-complex redox couple.

Counter electrodes from Mo–Se nanosheet alloys for bifacial dye-sensitized solar cells

“…When applied as windows, roof panels, or portable sources, the resultant solar panels are expected to have superiorities in fast start-up, multiple start/off capability, and stable photocurrent [34]. Fig.…”

“…In addition, the limiting diffusion current density (J lim ), intersection of cathodic branch with Y-axis, can be used to analyze the diffusion process of I À /I 3 À redox couples on a CE. J lim is in a linear relationship with diffusion coefficient (D n ): J lim ¼ 2nD n CN A /l [34], where l is the spacer thickness, C is the concentration of I 3 À species, N A is the Avogadro constant. Both J lim and D n vary in the order of Mo 0.6 Se > Mo 0.4 Se > Mo 0.8 Se > MoSe > Mo 0.2 Se > Se > Mo, which is consistent with CV analysis.…”

In situ chemical vapor deposition growth of carbon nanotubes on hollow CoFe2O4 as an efficient and low cost counter electrode for dye-sensitized solar cells

“…However, its cost and the scarcity limit its large-scale application [8]. What is more, unstable against corrosion of Pt CE in I 3 À /I À electrolyte is reported in the reference [9]. Recently, Pt-free counter electrodes, such as carbon materials [10e12], conductive polymers [13,14] and transition metal compounds [15e18], have been paid considerable attention for their low cost, favorable conductivity and catalytic activities.…”

Nitrogen plasma modified CVD grown graphene as counter electrodes for bifacial dye-sensitized solar cells

“…To address these challenges, various carbon materials, such as carbon black [10], porous carbon [11], carbon nanotubes [12,13], and graphene [14][15][16], were under remarkable investigations due to their excellent electrical conductivity and low cost, as well as high specific surface areas and good chemical stability, enabling them to serve as potential candidates to replace Pt CEs. Among them, graphene, a flat monolayer of sp 2 hybridized carbon atoms tightly packed into 2D honeycomb crystal lattices [17], is preferable over other carbon allotropes as transparent CE material for DSSCs [18].…”

“…The efficient electrocatalytic graphene for electrochemical reactions can be achieved by creating the catalytically active sites in graphene while maintaining its high charge mobility. More recently, considerable efforts have been devoted to introduce heteroatoms, such as nitrogen, boron and etc., into graphene oxide [20,21] or graphene nanoplatelets [16,22] for improvement of their electrocatalytic activity. To the best of our knowledge, little attention has been focused on graphene films grown by chemical vapour deposition (CVD) as CEs for the DSSCs, which is due to the inert nature of the pristine graphene with limited defects or edge planes.…”