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Research · Publication & note

October 27, 2006 September 9, 2026

Apollony photonic sponge based photoelectrochemical solar cells - Notes

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Published abstract

We have developed a quasi-fractal colloidal crystal to localize efficiently photons in a very broad optical spectral range; it has been applied to prepare dye sensitized photoelectrochemical solar (PES) cells able to harvest very efficiently photons from the ultraviolet (UV) and the visible (VIS) regions of the solar spectrum.

Figures

Complete original Figure 1 composition extracted directly from the embedded PDF image
Figure 1. Summary. Scheme of the 2D projection of an Apollony fractal distribution.

Source: F. Ramiro-Manzano et al., Chem. Commun., 242-244 (2007). Reproduced with permission from the Royal Society of Chemistry.

Complete original Figure 2 composition extracted directly from the embedded PDF image
Figure 2. Summary. SEM images of titania nanoparticles arranged in a photonic-sponge architecture (a) or in a packed manner (b). One can see in (a) how the smaller cavities arrange in the regions between the larger ones.

Source: F. Ramiro-Manzano et al., Chem. Commun., 242-244 (2007). Reproduced with permission from the Royal Society of Chemistry.

Complete original Figure 3 composition extracted directly from the embedded PDF image
Figure 3. Summary. Inverse of transmittance versus wavelength for a TiO2 thin film made of nanoparticles with a photonic-sponge topology (continuous line) and a plain film (dashed line).

Source: F. Ramiro-Manzano et al., Chem. Commun., 242-244 (2007). Reproduced with permission from the Royal Society of Chemistry.

Complete original Figure 4 composition extracted directly from the embedded PDF image
Figure 4. Summary. (a) I-V characteristic of dye-sensitized photoelectrochemical solar cells under AM 1.5 conditions, and (b) photocurrent spectra for standard (dashed line) and photonic-sponge (continuous line) titania electrodes.

Source: F. Ramiro-Manzano et al., Chem. Commun., 242-244 (2007). Reproduced with permission from the Royal Society of Chemistry.

Chemical Communications Number 3 cover featuring the Apollony photonic sponge photoelectrochemical solar cells article
Journal cover. Chemical Communications, Number 3 (21 January 2007), featuring “Apollony photonic sponge based photoelectrochemical solar cells” on pp. 242-244.

© The Royal Society of Chemistry 2007. Reproduced by an author with acknowledgement. Article: F. Ramiro-Manzano et al., Chem. Commun., 2007, 242-244, DOI 10.1039/B613422J.

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Related publications

Connections within F. Ramiro-Manzano's publication record, selected from shared research topics and evidence reviewed in the source papers.

Complete cross-sectional SEM image of a TiO2 photonic-sponge film
Journal article
Photochem. Photobiol. Sci. 7, 931-935 (2008)
Enhancement of TiO2 photocatalytic activity by structuring the photocatalyst film as photonic sponge
E. Carbonell, F. Ramiro-Manzano, I. Rodríguez, A. Corma, F. Meseguer and H. García

What the related paper adds

This later paper extends the research direction developed in Apollony photonic sponge based photoelectrochemical solar cells. This study takes the photonic-sponge concept beyond photovoltaics and applies it directly to photocatalysis. Without changing the TiO2 chemistry, the multiscale void network increases photon residence near the absorption edge and produces a much larger degradation rate, revealing how physical architecture alone can raise catalytic efficiency.

What this paper adds to the related work

This paper provides an earlier basis for the later development reported in Enhancement of TiO2 photocatalytic activity by structuring the photocatalyst film as photonic sponge. This work replaces the narrow spectral action of a periodic photonic crystal with a highly porous, quasi-fractal photonic sponge. Its interconnected cavities span several sizes, trap light across the near-ultraviolet and visible ranges, and turn broad-band scattering into a concrete strategy for improving dye-sensitized photoelectrochemical solar cells.

Complete original Figure 2 composition extracted directly from the article PDF
Journal article
J. Mater. Chem. 17, 3205-3209 (2007)
Solar energy harvesting in photoelectrochemical solar cells
I. Rodriguez, F. Ramiro-Manzano, P. Atienzar, J. M. Martinez, F. Meseguer, H. Garcia and A. Corma

What the related paper adds

This later paper extends the research direction developed in Apollony photonic sponge based photoelectrochemical solar cells. This paper compares the principal optical routes developed for titania photoelectrochemical cells instead of treating them separately. It places inverse opals and photonic sponges in the same device-level framework, shows broad photocurrent enhancement from the sponge architecture, and also tests corrugated metal electrodes as a route to improved charge collection.

What this paper adds to the related work

This paper provides an earlier basis for the later development reported in Solar energy harvesting in photoelectrochemical solar cells. This work replaces the narrow spectral action of a periodic photonic crystal with a highly porous, quasi-fractal photonic sponge. Its interconnected cavities span several sizes, trap light across the near-ultraviolet and visible ranges, and turn broad-band scattering into a concrete strategy for improving dye-sensitized photoelectrochemical solar cells.

SEM image of a titania inverse opal electrode with a 2 micrometre scale bar
Journal article
Photonics Nanostruct. Fundam. Appl. 3, 148-154 (2005)
Photonic crystals for applications in photoelectrochemical processes: Photoelectrochemical solar cells with inverse opal topology
I. Rodriguez, P. Atienzar, F. Ramiro-Manzano, F. Meseguer, A. Corma and H. Garcia

What the related paper adds

This earlier paper establishes a scientific basis for Apollony photonic sponge based photoelectrochemical solar cells. This paper establishes inverse-opal metal-oxide architectures as optically monitorable materials for photochemistry. It follows template infiltration and removal through reflectance, extends the method across several oxides, and demonstrates that a titania inverse opal can improve a photoelectrochemical solar cell by controlling photon propagation inside the active material.

What this paper adds to the related work

Building on the earlier contribution Photonic crystals for applications in photoelectrochemical processes: Photoelectrochemical solar cells with inverse opal topology, this paper advances the research line. This work replaces the narrow spectral action of a periodic photonic crystal with a highly porous, quasi-fractal photonic sponge. Its interconnected cavities span several sizes, trap light across the near-ultraviolet and visible ranges, and turn broad-band scattering into a concrete strategy for improving dye-sensitized photoelectrochemical solar cells.

Research fields

Bottom-up

TiO₂ nanoparticles form an Apollonian photonic sponge in which smaller voids occupy the spaces between larger ones. This hierarchical, fractal-like packing creates a broad distribution of scattering lengths within the photoelectrode.

Characterization

SEM verifies the nested pore morphology, while transmittance and device current-voltage measurements compare it with a densely packed TiO₂ film. The enhanced photocurrent is traced to broadband photon trapping near the titania absorption edge rather than to added absorber mass.

RESEARCH TOPICS

HarvestingAlthough the porous sponge contains about 3.7 times less photoactive material because its void fraction is roughly 85%, it traps incident light efficiently across the useful UV-visible range. The relevant result is therefore the response obtained per amount of TiO2, not simply the absolute current of a thicker conventional film.InterferenceUnlike an inverse opal, whose slowdown is concentrated near a photonic-band edge, the sponge uses multiple scattering from a hierarchy of cavity sizes. The broad response follows from the absence of a single periodicity and complements narrow-band Bragg localisation.MaterialsThe inverse sponge is templated from latex spheres of 1500, 400, 300 and 150 nm mixed in an 82:12:4:2 ratio to approximate quasi-Apollony packing. Its extreme porosity reduces active mass but increases optical path length and access to the internal surface, making topology a measurable material parameter rather than decorative porosity.ChemistryThe study explicitly notes that the chosen pH of 3 and modified synthesis are not the recipe for a high-efficiency Grätzel cell; absolute efficiencies are therefore low. That caveat is scientifically important: the experiment is a proof of the photonic-sponge light-harvesting mechanism, while gentler synthesis or more robust templates would be needed to combine it with optimized charge-transfer chemistry.
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