The Effect of Hole Transport Material Pore Filling on Photovoltaic Performance in Solid‐State Dye‐Sensitized Solar Cells

Melas-Kyriazi, John; Ding, I‐Kang; Marchioro, Arianna; Punzi, Angela; Hardin, Brian E.; Burkhard, George F.; Tétreault, Nicolas; Grätzel, Michaël; Moser, Jacques-E.; McGehee, Michael D.

doi:10.1002/aenm.201100046

Cited by 132 publications

(110 citation statements)

References 47 publications

Supporting

Mentioning

105

Contrasting

Order By: Relevance

“…16 Some studies have already argued that hole transport between dyes could happen in solid state devices and plays a role towards improved dye regeneration. 17,8,18,19,20,9 However, to our knowledge, no experimental evidence for this has been reported to date.…”

Section: Introductionmentioning

confidence: 62%

“…5,6,7,8,9 Some of these studies have shown that, under optimized conditions and for different dyes and thickness of the TiO2 layer, the dye regeneration yield of the device ranges between 0.9 and 1. This result suggests that either almost complete coverage of the dyed surface is achievable or transfer of holes between the dye molecules enables improved charge collection from dyes that are uncovered by the HTM.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The Role of Hole Transport between Dyes in Solid-State Dye-Sensitized Solar Cells

Moia¹,

Cappel²,

Leijtens

et al. 2015

J. Phys. Chem. C

View full text Add to dashboard Cite

In dye-sensitized solar cells (DSSCs) photo-generated positive charges are normally considered to be carried away from the dyes by a separate phase of hole transporting material (HTM). We show that there can also be significant transport within the dye monolayer itself before the hole reaches the HTM. We quantify the fraction of dye regeneration in solid state DSSCs that can be attributed to this process. By using cyclic voltammetry and transient anisotropy spectroscopy we demonstrate that the rate of inter-dye hole transport is prevented both on micrometer and nanometer length scales by reducing the dye loading on the TiO2 surface. The dye regeneration yield is quantified for films with high and low dye loadings (with and without hole percolation in the dye monolayer) infiltrated with varying levels of HTM. Inter-dye hole transport can account for >50% of the overall dye regeneration with low HTM pore filling. This is reduced to about 5% when the infiltration of the HTM in the pores is optimized in 2μm thick films. Finally, we use hole transport in the dye monolayer to characterize the spatial distribution of the HTM phase in the pores of the dyed mesoporous TiO2.

show abstract

Section: Introductionmentioning

confidence: 62%

Section: Introductionmentioning

confidence: 99%

The Role of Hole Transport between Dyes in Solid-State Dye-Sensitized Solar Cells

Moia¹,

Cappel²,

Leijtens

et al. 2015

J. Phys. Chem. C

View full text Add to dashboard Cite

show abstract

“…All cells made from higher spiro-concentrations have similar electron lifetimes, with overlapping points at all studied bias light intensities. These results are in good agreement with a study by Melas-Kyriazi et al, where improved pore-filling was found to extend the electron lifetime at short circuit to around 10 ms. 41 While the electron lifetime increases for high pore-filling fractions, no trend was observed in the extraction lifetimes at high light bias, as shown in Figure 6b, where most measurement points overlap.…”

Section: Solid-state Dye-sensitized Solar Cellsmentioning

confidence: 79%

Pore Filling of Spiro‐OMeTAD in Solid‐State Dye‐Sensitized Solar Cells Determined Via Optical Reflectometry

Docampo

Hey

Guldin

et al. 2012

Adv Funct Materials

View full text Add to dashboard Cite

Here, we present an optical probe to determine the pore-filling fraction of the hole-conductor 2,2-7,7-tetrakis-N,N-di-pmethoxyphenylamine-9,9-spirobifluorene (spiro-OMeTAD) into mesoporous photoanodes in solid-state dye-sensitized solar cells (ss-DSCs). Based on refractive index determination by the film's reflectance spectra, and using effective medium approximations, we can extract the volume fractions of the constituent materials and hence quantify pore-filling. This non-destructive method can be used with complete films and does not require detailed model assumptions.pore-filling fractions of up to 80% were estimated for optimized solid-state DSC photoanodes, which is higher than that previously estimated by indirect methods.Additionally, we have determined transport and recombination lifetimes as a function of the pore-filling fraction via photovoltage and photocurrent decay measurements. While extended electron lifetimes were observed with increasing pore-filling fractions, no trend was found in the transport kinetics. The data suggests that a pore-filling fraction of at least 60% is necessary to achieve optimized performance in ss-DSCs. This degree of pore-filling is even achieved in 5 µm thick mesoporous photoanodes. We can therefore conclude from this study that pore-filling is not a limiting factor in the fabrication of thick ss-DSCs.

show abstract

“…The hydrophobic dinonyl aliphatic moiety of Z907 allows for a better wetting of the dye-sensitized surface by the organic HTM and the formation of a more conformal heterojunction. 34 Hence, its use is preferred to that of N719 dye in the fabrication of efficient solid-state DSSCs. Upon pulsed laser excitation, solid-state samples displayed a steep rise of transient absorption observed at short times, corresponding to the appearance of the oxidized state of the dye produced by ultrafast electron injection ( Figure 4A).…”

mentioning

confidence: 99%

Dynamics of Interfacial Charge Transfer States and Carriers Separation in Dye-Sensitized Solar Cells: A Time-Resolved Terahertz Spectroscopy Study

et al. 2015

Self Cite

View full text Add to dashboard Cite

Electron injection from a photoexcited molecular sensitizer into a wide-bandgap semiconductor is the primary step toward charge separation in dye-sensitized solar cells (DSSCs). According to the current understanding of DSSCs functioning mechanism, charges are separated directly during this primary electron transfer process, yielding hot conduction band electrons in the semiconductor and positive holes localized on oxidized dye molecules at the surface. Comparing results of ultrafast transient absorption and time-resolved terahertz measurements, we show here that intermediate interfacial charge transfer states (CTSs) are rather formed upon ultrafast injection from photoexcited Ru(II)− bipyridyl dye-sensitizer molecules into mesoporous TiO 2 films. Formation and dissociation of these CTSs were found to strongly depend on their ionic environment and excess excitation energy. This finding establishes a new mechanism for charge separation in DSSCs. It also offers a rationale for the effect of electrolyte composition in liquid-based devices and of ion doping in solid-state solar cells under working conditions.

show abstract

The Effect of Hole Transport Material Pore Filling on Photovoltaic Performance in Solid‐State Dye‐Sensitized Solar Cells

Cited by 132 publications

References 47 publications

The Role of Hole Transport between Dyes in Solid-State Dye-Sensitized Solar Cells

The Role of Hole Transport between Dyes in Solid-State Dye-Sensitized Solar Cells

Pore Filling of Spiro‐OMeTAD in Solid‐State Dye‐Sensitized Solar Cells Determined Via Optical Reflectometry

Dynamics of Interfacial Charge Transfer States and Carriers Separation in Dye-Sensitized Solar Cells: A Time-Resolved Terahertz Spectroscopy Study

Contact Info

Product

Resources

About