Phase separation in vacuum codeposited pentacene/6,13-pentacenequinone thin films

Journal Article · Tue May 01 00:00:00 EDT 2007 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PHYSREVB.75.174108· OSTI ID:20957826

Salzmann, Ingo; Opitz, Ricarda; Rogaschewski, Siegfried; Rabe, Juergen P; Koch, Norbert; Nickel, Bert ^[1]

---

1. Institut fuer Physik, Humboldt-Universitaet zu Berlin, Newtonstrasse 15, D-12489 Berlin (Germany)

Pentacene (P) and 6,13-pentacenequinone (PQ) have been vacuum codeposited onto SiO{sub 2} in order to control phase separation in thin films for the application as bulk heterojunctions in organic photovoltaic devices. Structural investigations by means of scanning electron microscopy (SEM) and atomic force microscopy revealed pronounced phase separation of the two materials at length scales that turned out to be tunable by the variation of the deposition rate. X-ray diffraction provided evidence for polymorphism in pure films of P and PQ on SiO{sub 2}. While pure films exhibited both the bulk and thin-film phase, the bulk phase is mainly suppressed within the co-deposited films (P+PQ). This was corroborated by Fourier-transform infrared spectroscopy results. SEM investigations of pure and codeposited films indicated that PQ bulk crystallites of up to 200 nm height form continuous paths to the substrate and grow within a matrix formed of P and PQ thin-film phases. The obtained heterojunction morphologies thus appear interesting for the application in organic-based photovoltaic cells.

• OSTI ID: 20957826
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Vol. 75, Issue 17; Other Information: DOI: 10.1103/PhysRevB.75.174108; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ATOMIC FORCE MICROSCOPY
CRYSTAL STRUCTURE
FOURIER TRANSFORM SPECTROMETERS
FOURIER TRANSFORMATION
HETEROJUNCTIONS
INFRARED SPECTRA
MORPHOLOGY
ORGANIC SEMICONDUCTORS
PENTACENE
PHOTOVOLTAIC CELLS
PHOTOVOLTAIC EFFECT
SCANNING ELECTRON MICROSCOPY
SILICA
SILICON OXIDES
THIN FILMS
VACUUM COATING
X-RAY DIFFRACTION