Electrostatic nanoassembly of contact interfacial layer for enhanced photovoltaic performance in polymer solar cells

Gopalan Sai-Anand, Anantha Iyengar Gopalan, Kwang Pill Lee, Swaminathan Venkatesan, Qiquan Qiao, Byoung Ho Kang, Sang Won Lee, Jae Sung Lee, Shin Won Kang

Research output: Contribution to journalArticlepeer-review

Abstract

Improved performance in the bulk heterojunction (BHJ) polymer solar cells (PSCs) can be achieved through multiple mechanisms by tuning the structure of the components and design architecture. Therefore, in this study, we designed and fabricated an electrostatically assembled contact interfacial layer utilizing the electrostatic interactions between positively charged poly(diallyldimethylammonium chloride) (PDDA) and negatively charged sulfonate ions in a polymer, i.e. toluene sulfonic acid incorporated self-doped polyaniline (SPAN(TSA-)) (designated as SPAN(TSA-)/EA-CIL). We investigated the influence of SPAN(TSA-)/EA-CIL on the photovoltaic performance of BHJ PSCs. We adopted a simple "dip-dry" technique to fabricate the SPAN(TSA-)/EA-CIL. Cyclic Voltammetry, X-ray photoelectron spectroscopy, Ultraviolet-visible spectroscopy, water contact angle measurements, electrochemical impedance spectroscopy and atomic force microscopy were employed to characterize the new SPAN(TSA-)/EA-CIL and to elucidate the associated enhancements in the photovoltaic performance. The fabricated PSCs with the SPAN(TSA-)/EA-CILs exhibited an improved photoconversion efficiency (PCE) through enhancement of both the short-circuit current density (JSC) and fill factor compared to the device consisting of only SPAN(TSA-) or PEDOT:PSS. A plausible mechanism is presented here that explains the enhanced JSC and PCE in terms of transient dipole induction at the SPAN(TSA-)/EA-CIL surface. Interestingly, the PCE of devices based on ITO/SPAN(TSA-)/EA-CIL(1:1)/P3HT:PC60BM/Al and ITO/SPAN(TSA-)/EA-CIL(1:1)/PBDTTT-C-T:PC70BM/Al was enhanced by 13% (3.19-3.67%) and 10% (5.11-5.60%) compared to those of devices based on ITO/PEDOT:PSS/P3HT:PC60BM/Al and ITO/PEDOT:PSS/PBDTTT-C-T:PC70BM/Al, respectively. The present work thus identifies a novel class of low-temperature processable interface layer with a potential to fabricate highly efficient photovoltaic devices.

Original languageEnglish (US)
Pages (from-to)148-163
Number of pages16
JournalSolar Energy Materials and Solar Cells
Volume153
DOIs
StatePublished - Aug 1 2016
Externally publishedYes

Keywords

  • Cationic electrolyte
  • Contact interfacial layer
  • Solar cell
  • Sulfonated polyaniline

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Surfaces, Coatings and Films

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