Carbonaceous Dye‐Sensitized Solar Cell Photoelectrodes

Abstract

High photovoltaic efficiency is one of the most important keys to the commercialization of dye sensitized solar cells (DSSCs) in the quickly growing renewable electricity generation market. The heart of the DSSC system is a wide bandgap semiconductor based photoelectrode film that helps to adsorb dye molecules and transport the injected electrons away into the electrical circuit. However, charge recombination, poor light harvesting efficiency and slow electron transport of the nanocrystalline oxide photoelectrode film are major issues in the DSSC's performance. Recently, semiconducting composites based on carbonaceous materials (carbon nanoparticles, carbon nanotubes (CNTs), and graphene) have been shown to be promising materials for the photoelectrode of DSSCs due to their fascinating properties and low cost. After a brief introduction to development of nanocrystalline oxide based films, this Review outlines advancements that have been achieved in the application of carbonaceous‐based materials in the photoelectrode of DSSCs and how these advancements have improved performance. In addition, several of the unsolved issues in this research area are discussed and some important future directions are also highlighted.

Incorporation of graphene into SnO2 photoanodes for dye-sensitized solar cells

“…would remain on the surface of RGO due to the partial reduction and these would interact with the polar groups on N719. These functional groups may be playing an important role in the dye adsorption [21]. SnO 2 would also interact with these polar groups.…”

“…In addition, the measured series resistance (R series ) of the TiO 2 -SnO 2 -RGO (0.45) based DSSC was 97.9 Ω, which was ~1.7-fold lower than that of the control cell ( We attribute this η decrease of the DSSCs with higher RGO loading to (i) opacity of the film (see films before dye adsorption in Fig. S3) reducing light absorption and (ii) high catalytic property of RGO, which has been shown to limit the continuous electron transfer at the photoanode [2,21,47].…”

“…Due to their excellent conductivity, carbon nanotubes (CNTs) and graphene can act to improve electron transport and reduce the charge recombination which results from sluggish charge transport of semiconducting oxide based photoanodes; thus significantly enhancing the PCE of PV cells [21][22][23][24][25][26]. Over the past few years, researchers have incorporated graphene derivatives into various TiO 2 structures and shown remarkable efficiency enhancement [27][28][29][30].…”

“…However, until now, there has been no report on the use of graphene structures in SnO 2 photoanodes for DSSCs. Moreover, the kinetics of dye adsorption and performance enhancement for carbonaceous photoanodes is still unclear, with some studies suggesting contrary results [21,28,29,31,32]. Therefore, exploring the effect of graphene or reduced graphene oxide (RGO) in SnO 2 photoanode based DSSCs would be valuable.…”

Review—Single-Walled Carbon Nanohorn-Based Dye-Sensitized Solar Cells

“…58,59 In other words, the electron-hole recombination rate has to be low for high power conversion efficiencies. 60,61 In this regard, the fraction between charge transport resistance (Rw) and the resistance toward recombination (R k ) defines the charge collection efficiency (η cc ) according to Equation 1.…”