Amphiphilic Diketopyrrolopyrrole Small Molecules with Enhanced Intermolecular Ordering for Organic Electronics
Location
Room 2904 B
Session Format
Paper Presentation
Research Area Topic:
Natural & Physical Sciences - Chemistry
Co-Presenters and Faculty Mentors or Advisors
Zilong Zheng1, Veaceslav Coropceanu1, Jean-Luc Bredas1,2, and John R. Reynolds1
1School of Chemistry and Biochemistry, School of Materials Science and Engineering, 901 Atlantic Drive, Georgia Institute of Technology, Atlanta, GA 30332, USA
2 Solar and Photovoltaics Engineering Research Center, Materials Science and Engineering, Physical Science and Engineering, 4700 King Abdullah University of Science & Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
Abstract
We have developed a family of novel π-conjugated donor-acceptor-donor (d-a-d) small molecules of amphiphilic nature, aiming to promote intermolecular ordering for enhanced charge separation and transport in organic photovoltaics (OPVs), and charge mobilities in organic thin-film transistors (OFETs). We selected diketopyrrolopyrrole (DPP) as the acceptor moieties that can be di-substituted with non-polar and polar functional groups, thereby providing the amphiphilic nature. Thienylene donor units were chosen due to their relatively low torsional energy barriers to planarity and π-stacking ability. This structural design resulted in materials with strong intermolecular order, which was confirmed by differential scanning calorimetry (DSC), showing two distinct crystallization features above 90 ˚C; the uniaxial alignment of the molecules led to strong birefringence observed via polarized optical microscopy, indicating strong order in the solid state. A high degree of crystallinity in the thin films was seen using grazing incidence wide angle x-ray scattering (GIWAXS). Langmuir-Blodgett (LB) films of well-ordered monolayers at an air-water interface were deposited onto metal oxide substrates; these films, consisting of mono- and multi-layers, were subjected to morphological and transport studies. The crystalline characteristics of these amphiphilic molecules should lead to high charge mobilities, ideal for OFET applications. These materials also exhibit broad absorption spectra extending into the near infrared, high extinction coefficients, and well-aligned energy levels for exciton dissociation at the donor-acceptor interface in OPV devices.
Keywords
Conjugated, Amphiphilic, Organic photovoltaics, Organic field effect transitor, Langmuir-Blodgett, Grazing incidence wide angle x-ray scattering, Organic synthesis
Presentation Type and Release Option
Presentation (Open Access)
Start Date
4-24-2015 9:30 AM
End Date
4-24-2015 10:30 AM
Recommended Citation
Lo, Chi Kin, "Amphiphilic Diketopyrrolopyrrole Small Molecules with Enhanced Intermolecular Ordering for Organic Electronics" (2015). GS4 Georgia Southern Student Scholars Symposium. 176.
https://digitalcommons.georgiasouthern.edu/research_symposium/2015/2015/176
Amphiphilic Diketopyrrolopyrrole Small Molecules with Enhanced Intermolecular Ordering for Organic Electronics
Room 2904 B
We have developed a family of novel π-conjugated donor-acceptor-donor (d-a-d) small molecules of amphiphilic nature, aiming to promote intermolecular ordering for enhanced charge separation and transport in organic photovoltaics (OPVs), and charge mobilities in organic thin-film transistors (OFETs). We selected diketopyrrolopyrrole (DPP) as the acceptor moieties that can be di-substituted with non-polar and polar functional groups, thereby providing the amphiphilic nature. Thienylene donor units were chosen due to their relatively low torsional energy barriers to planarity and π-stacking ability. This structural design resulted in materials with strong intermolecular order, which was confirmed by differential scanning calorimetry (DSC), showing two distinct crystallization features above 90 ˚C; the uniaxial alignment of the molecules led to strong birefringence observed via polarized optical microscopy, indicating strong order in the solid state. A high degree of crystallinity in the thin films was seen using grazing incidence wide angle x-ray scattering (GIWAXS). Langmuir-Blodgett (LB) films of well-ordered monolayers at an air-water interface were deposited onto metal oxide substrates; these films, consisting of mono- and multi-layers, were subjected to morphological and transport studies. The crystalline characteristics of these amphiphilic molecules should lead to high charge mobilities, ideal for OFET applications. These materials also exhibit broad absorption spectra extending into the near infrared, high extinction coefficients, and well-aligned energy levels for exciton dissociation at the donor-acceptor interface in OPV devices.
