Nitrogen‐Doped Carbon Nano‐Onions Decorated on Graphene Network: A Novel All‐Carbon Composite Counter Electrode for Dye‐Sensitized Solar Cell with a 10.28% Power Conversion Efficiency

Abstract

A desirable counter electrode material for dye‐sensitized solar cells (DSSCs) needs to have superior electrocatalytic activity, low charge‐transfer resistance, and long‐term stability. Herein, the development of a composite of nitrogen‐doped carbon nano‐onions with modified reduced graphene (N‐CNOs/mGr) to achieve these merits is reported. The mGr network has high electrical conductivity to improve charge transfer; the N‐CNOs with pyridinic and graphitic N provide more electrocatalytic active sites for the reduction of I3− to I−, and the carbon composite demonstrates excellent electrochemical stability. The constructed DSSC with the N‐CNOs/mGr electrode presents better long‐term stability and a higher power conversion efficiency of 10.28% than those devices with conventional Pt (6.54%) and mGr (5.11%) electrodes. Therefore, the all carbon‐based composite will open up new opportunities for a variety of electrochemical device applications.

Recent Advances on Pt-Free Electro-Catalysts for Dye-Sensitized Solar Cells

“… The SEM images of ( a ) HMC2021 [ 48 ], ( b ) CA-C [ 49 ], ( c ) N-CNOs/mGr [ 50 ], ( d ) N-GHBs (inset shows their TEM images) [ 52 ], and ( e ) N,S-GHBs [ 53 ]. …”

“…Pang et al synthesized N-doped carbon nano-onion (N-CNO) with modified graphene (mGr). The diameter of N-CNO and the thickness of mGr were 40–60 nm and 10–30 nm, respectively, as shown in Figure 3 c [ 50 ]. The N-CNOs/mGr showed the best η of the 10.28% among the mGr (5.11%), and the Pt (6.54%), as shown in Table 1 .…”

Sodium Molybdate-Assisted Synthesis of a Cobalt Phosphide Hybrid Counter Electrode for Highly Efficient Dye-Sensitized Solar Cells

“…As third-generation solar cells, dye-sensitized solar cells (DSSCs) have the advantages of low cost, environmental friendliness, and requirement of a simple preparation process when compared to the traditional silicon-based solar cells. , The main function of the counter electrode (CE), which is one of the key parts of the DSSCs, is the reduction of oxidation ions in the electrolyte to maintain an equilibrium state of the redox couple in the I – /I 3 – electrolyte. , The typical electrode material is platinum (Pt), which has superior electrocatalytic activity and electrical conductivity. , However, its noble metal property leads to high cost ($4.6/m 2 for a 5 nm thick Pt film) of DSSCs, which tremendously limits the large-scale fabrication of DSSCs . To solve this problem, many non-Pt and low-Pt CE materials have been developed, including carbon materials, carbides, sulfides, conductive polymers, selenides, metals and their composites, and so on. − Compared with the abovementioned CE materials, transition-metal phosphides have been widely used in electrolysis of water and photocatalytic hydrogen evolution reactions due to their efficient electrocatalytic activity for the hydrogen evolution reaction, high mechanical strength, good electrical conductivity, and durability in acidic and basic media − and have been rarely used as CE catalysts for DSSCs. Among these metal phosphides, cobalt phosphide (CoP) has shown good hydrogen evolution reaction catalytic ability, but it showed inferior catalytic activity to those of noble metals. , The introduction of “collaborators” is an effective approach to reduce the adsorption energy and further improve the catalytic performance of CoP.…”

Adsorptive removal of Rhodamine B dye from aqueous solution by using graphene–based nickel nanocomposite

“…In another case, along with synthesis and characterization and preliminary degradation of RhB dye removal, they have verified the usage of composite for electrode material as super capacitors [ 13 ]. The graphene based nanocomposites are also used in devices like dye sensitized solar cell [ 14 ], enhanced X-ray photon response [ 15 ], enhanced performance of light-controlled conductive switching [ 16 ], and photocatalytic activity in semiconductor [ 17 ].…”