Analysis of improved photovoltaic properties of pentacene/C60 organic solar cells: Effects of exciton blocking layer thickness and thermal annealing

Seunghyup Yoo, William J. Potscavage, Benoit Domercq, Sung Ho Han, Tai De Li, Simon C. Jones, Robert Szoszkiewicz, Dean Levi, Elisa Riedo, Seth R. Marder, Bernard Kippelen

Research output: Contribution to journalArticle

Abstract

We report on the photovoltaic properties of organic solar cells based on pentacene and C60 thin films with a focus on their spectral responses and the effect of thermal annealing. Spectra of external quantum efficiency (EQE) are measured and analyzed with a one-dimensional exciton diffusion model dependent upon the complex optical functions of pentacene films, which are measured by spectroscopic ellipsometry. An improvement in EQE is observed when the thickness of the bathocuproine (BCP) layer is decreased from 12 nm to 6 nm. Detailed analysis of the EQE spectra indicates that large exciton diffusion lengths in the pentacene films are responsible for the overall high EQE values near wavelengths of 668 nm. Analysis also shows that improvement in the EQE of devices with the thinner BCP layer can be attributed to a net gain in optical field distribution and improvement in carrier collection efficiency. An improvement in open-circuit voltage (VOC) is also achieved through a thermal annealing process, leading to a net increase in power conversion efficiency. Integration of the EQE spectrum with an AM1.5 G spectrum yields a predicted power conversion efficiency of 1.8 ± 0.2%. The increase in VOC is attributed to a significant reduction in the diode reverse saturation current upon annealing.

Original languageEnglish (US)
Pages (from-to)1367-1375
Number of pages9
JournalSolid-State Electronics
Volume51
Issue number10 SPEC. ISS
DOIs
StatePublished - Jan 1 2007

Fingerprint

Quantum efficiency
Excitons
quantum efficiency
solar cells
excitons
Annealing
annealing
volatile organic compounds
Volatile organic compounds
Conversion efficiency
Spectroscopic ellipsometry
Open circuit voltage
diffusion length
open circuit voltage
spectral sensitivity
ellipsometry
Hot Temperature
Organic solar cells
pentacene
LDS 751

Keywords

  • Annealing
  • Exciton
  • Fullerene
  • Organic solar cells
  • Pentacene
  • Spectral modeling

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Materials Chemistry

Cite this

Analysis of improved photovoltaic properties of pentacene/C60 organic solar cells : Effects of exciton blocking layer thickness and thermal annealing. / Yoo, Seunghyup; Potscavage, William J.; Domercq, Benoit; Han, Sung Ho; Li, Tai De; Jones, Simon C.; Szoszkiewicz, Robert; Levi, Dean; Riedo, Elisa; Marder, Seth R.; Kippelen, Bernard.

In: Solid-State Electronics, Vol. 51, No. 10 SPEC. ISS, 01.01.2007, p. 1367-1375.

Research output: Contribution to journalArticle

Yoo, S, Potscavage, WJ, Domercq, B, Han, SH, Li, TD, Jones, SC, Szoszkiewicz, R, Levi, D, Riedo, E, Marder, SR & Kippelen, B 2007, 'Analysis of improved photovoltaic properties of pentacene/C60 organic solar cells: Effects of exciton blocking layer thickness and thermal annealing', Solid-State Electronics, vol. 51, no. 10 SPEC. ISS, pp. 1367-1375. https://doi.org/10.1016/j.sse.2007.07.038
Yoo, Seunghyup ; Potscavage, William J. ; Domercq, Benoit ; Han, Sung Ho ; Li, Tai De ; Jones, Simon C. ; Szoszkiewicz, Robert ; Levi, Dean ; Riedo, Elisa ; Marder, Seth R. ; Kippelen, Bernard. / Analysis of improved photovoltaic properties of pentacene/C60 organic solar cells : Effects of exciton blocking layer thickness and thermal annealing. In: Solid-State Electronics. 2007 ; Vol. 51, No. 10 SPEC. ISS. pp. 1367-1375.
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