Carbonized Eggshell Membranes as a Natural and Abundant Counter Electrode for Efficient Dye‐Sensitized Solar Cells

Abstract

recognized as a potential substitute for the typical Pt electrode. For instance, the macroporous structure (beyond 50 nm) of carbonized sea tangle and the mesoporous structure (2-50 nm) of carbonized oak have been explored by, respectively, Grätzel's group and Gao's group. [ 5,6 ] However, the relationships between the electrochemical activity and the microstructure remain unclear and naturally derived CEs composed of micropores (less than 2 nm) have not yet been applied to DSSCs as CEs.In this communication, we present a naturally derived carbonaceous material as a Pt-free CE for DSSCs. The material was made from eggshell membranes that were recycled from domestic waste. It is found that the unique micropore-rich, hierarchically porous microstructure of eggshell membranes can effectively facilitate the charge-transfer process, leading to an improved open-circuit voltage V oc and a competitive efficiency as compared with a DSSC with a traditional Pt-based CE.Figure 1 a shows the scanning electron microscopy (SEM) image of an eggshell membrane before carbonization. It exhibits an entangled architecture of interwoven coalescing fi bers, which form a highly porous microstructure. To further enhance the electrical conductivity, the carbonized eggshell membranes were surface coated with a layer of carbon. The carbonized sucrose-coated eggshell membranes (CSEMs) were prepared by immersing the fresh eggshell membranes into a sucrose solution and then carbonizing at 800 °C. The uniformly coarsened and thickened morphology of the CSEM inThe ultimate goal of renewable solar energy is aimed at developing low-cost, high-effi ciency photovoltaic technologies that can satisfy the demand for future terawatt-scale solar energy. The dye-sensitized solar cells (DSSC), with a light-electricity conversion effi ciency exceeding 12%, are considered to be one of the most promising candidates for next-generation solar cells due to their facile assembly, cost-effectiveness, and environmental friendliness. [ 1 ] The prototypical architecture of a DSSC consists of a porous fi lm of n-type TiO 2 , a photosensitized dye, a redox couple consisting of I /I 3 − − Ielectrolyte, and a Pt counter electrode (CE). The noble and scarce nature of Pt as well as its poor stability in the electrolyte has become a signifi cant hurdle to realize low-cost, and thus, large-scale, deployment of DSSCs. Upon solar illumination, the dye molecule undergoes an electronic transition from the ground state to the excited state. This is followed by an ultrafast electron injection from the excited state of the dye molecule into the conduction band of TiO 2 , which leads to the oxidation of the dye molecule. The oxidized dye subsequently stimulates the oxidation of iodide into triiodide in the electrolyte, and the electron injected into the conduction band of TiO 2 is transported to the CE. The function of the CE is to regenerate iodide from triiodide in order to complete the light-electricity conversion process. Accordingly, the electrical properties and catalytic abi...

Dual-template synthesis of N-doped macro/mesoporous carbon with an open-pore structure as a metal-free catalyst for dye-sensitized solar cells

“…16053) to improve the adhesion of the counter electrode to the fluorine doped tin oxide (FTO) substrate for a robust counter electrode (CE). The ink for the doctor-blade coating was prepared with 50 mg of macro/meso-NC, 50 mg of CP, 1 mL of isopropanol and 0.05 mL of ethylene glycol (EG) [13]. The sample with a desirable thickness onto a FTO substrate was made by coating two times and calcining at 350 C for 15 min under Ar flow.…”

“…Several carbonaceous materials have been explored, such as activated carbon [7], carbon black [8], graphite [9], graphene [10], mesoporous carbon [11], carbon nanotube [12], bio-derived carbon [13], etc. The catalytic activity of carbonaceous materials strongly relies on their microstructure and morphology which determines the amount of active sites and the diffusion property of redox species within the catalyst layer.…”

Floating, Flexible Polymeric Dye‐Sensitized Solar‐Cell Architecture: The Way of Near‐Future Photovoltaics

“…[ 9 ] In this context, dye-sensitized solar cells (DSCs) [ 10 ] may represent a solution to the issues related to fl oating silicon-based technologies. DSCs are constituted of abundant materials, industrially processable under mild conditions, [ 11 ] and can function well in a wide range of sunlight angles and intensities, [ 12 ] thus an inbuilt tracking system is not necessary. In addition, a DSC can easily be made partially transparent, [ 13 ] which therefore reduces both lighting and landscape pollution.…”

Facile and quick preparation of carbon nanohorn-based counter electrodes for efficient dye-sensitized solar cells

“…[4][5][6] There have been several attempts to substitute Pt, while still maintaining a good performance. Firstly, transition metal complexes (TMC) are widely used due to activities similar to that of Pt.…”

“…3 The usage of rare metals including platinum (Pt) in counter electrodes (CE) raises the overall production costs, and, as such, constitutes a major bottleneck in terms of its introduction into the market. [4][5][6] There have been several attempts to substitute Pt, while still maintaining a good performance. Firstly, transition metal complexes (TMC) are widely used due to activities similar to that of Pt.…”