Dye Nanoaggregate Structures in MK-2, N3, and N749 Dye···TiO2 Interfaces That Represent Dye-Sensitized Solar Cell Working Electrodes
[2];
[4];
- Univ. of Cambridge (United Kingdom); Science and Technology Facilities Council (STFC), Oxford (United Kingdom). Rutherford Appleton Lab. (RAL)
- Univ. of Cambridge (United Kingdom); Science and Technology Facilities Council (STFC), Oxford (United Kingdom). Rutherford Appleton Lab. (RAL); Argonne National Lab. (ANL), Lemont, IL (United States)
- Science and Technology Facilities Council (STFC), Oxford (United Kingdom). Diamond Light Source, Ltd.
- Argonne National Lab. (ANL), Lemont, IL (United States)
- Science and Technology Facilities Council (STFC), Oxford (United Kingdom). Rutherford Appleton Lab. (RAL)
The working electrode of a dye-sensitized solar cell (DSSC) consists of dye molecules adsorbed onto nanoparticles of a semiconductor such as TiO2. A reliable prediction of the DSSC photovoltaic performance of a given dye requires in-depth knowledge about the precise structure of the dye···TiO2 interface. In this work, X-ray reflectometry (XRR) and grazing-incidence small-angle X-ray scattering (GISAXS) are employed to determine the dye···TiO2 interfacial structure and associated dye aggregation behavior of three high-performance DSSC dyes, i.e., a metal-free organic dye, MK-2, and the two archetypal ruthenium-based organometallic dyes, N3 and N749 (Black Dye). Results show that all three dyes form nanoaggregates in dye···TiO2 interfaces. We determine the dye nanoaggregate separations, sizes, distribution densities, and the extent of short-range order within each dye self-assembly in the longitudinal and lateral directions. Dye···TiO2 composites fabricated using dye solutions of varying concentrations are analyzed. We find that nanoaggregates of the three dyes are separated by several hundred nanometers (158-203 nm) in dye···TiO2 interfaces that have been fabricated using concentrated dye solutions (0.5 mM or 1.0 mM). MK-2 and N749 dyes also display smaller interparticle separations. Dye nanoparticle diameters are of the order of 156-198 nm, sizes that are comparable to the largest interparticle separations. Thus, no extraneous dye particles can be fitted into gaps between particles, so the dye self-assembly is saturated. Self-assemblies of all three dyes exhibit both lateral and longitudinal short-range order; N3 displays a particularly short coherence length along the TiO2 surface, with extensive structured disorder along the longitudinal direction. The operation of DSSC working electrodes would therefore seem to be dependent on a dye self-assembly that may exhibit several levels of structural granularity and dye aggregation effects.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); 1851 Royal Commission; Science and Technology Facilities Council (STFC)
- Grant/Contract Number:
- AC02-06CH11357
- OSTI ID:
- 1606547
- Journal Information:
- ACS Applied Energy Materials, Vol. 3, Issue 1; ISSN 2574-0962
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Similar Records
Hierarchically macro–mesoporous TiO{sub 2} film via self-assembled strategy for enhanced efficiency of dye sensitized solar cells
Pomegranate leaves and mulberry fruit as natural sensitizers for dye-sensitized solar cells