Solid polymer electrolytes consisting of NaI and I 2 dissolved in poly(butyl acrylate) (PBA, M w=99,000 g/mol) were prepared and applied to dye-sensitized solar cells (DSSC). Upon incorporation of salt, the free ester carbonyl stretching bands of PBA in FT-IR spectra shift to a lower wave number, confirming the complex formation between sodium ions and carbonyl oxygens. Coordinative interactions and structural changes of the PBA/NaI/I 2 electrolytes have been also characterized by X-ray photoelectron spectroscopy (XPS), wide angle X-ray scattering (WAXS) and differential scanning calorimetry (DSC). The conversion efficiency of DSSC employing PBA/NaI/I 2 electrolytes (1.66% at 10 mW/cm 2) is unexpectedly much higher than that employing poly(ethylene oxide) (PEO, M w=1,000,000 g/mol)/NaI/I 2 (0.07%), although the ionic conductivity of the former (2.1×10 -6 S/cm at room temperature) is not greatly different from that of the latter (1.6×10 -6 S/cm). The significantly improved solar cell performance is mostly attributed to (1) the easier penetration of PBA through TiO 2 nanoporous layer due to its lower molecular weight, and (2) the sticky property of PBA to allow a better adhesion with the electrodes.
Bibliographical noteFunding Information:
The authors gratefully acknowledge the financial support of the Ministry of Science and Technology of Korea through the Creative Research Initiatives Program.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics