Structural Dynamics of Polymer:Non-Fullerene Organic Solar Cell Blends: A Neutron Spectroscopy Perspective

Abstract

Organic solar cells (OSCs) based on ADA-type (acceptor-donor-acceptor) nonfullerene acceptors (NFAs) exhibit improved power conversion efficiency (PCE) compared to the conventional fullerene-based analogues. The optoelectronic properties of the OSC active layer are correlated to the underlying structural dynamics of the active layer blend, and therefore influence the device performance. Using synergistically different neutron spectroscopy techniques, we studied the dynamics of binary and ternary blends made of the non-fullerene acceptors O-IDTBR and O-IDFBR, and the regioregular donor polymer poly(3-hexylthiophene) (P3HT). Considering key factors like structural relaxation, miscibility and morphology, within a chosen temperature range, we probed the dynamical responses of the neat phases and the blends using time-of

Dynamics of Polyalkylfluorene Conjugated Polymers: Insights from Neutron Spectroscopy and Molecular Dynamics Simulations

“…Quasi-elastic neutron scattering (QENS) is a neutron spectroscopy technique that, although offering an appropriate framework to probe microscopic time and length scales matching the structural dynamics of such materials, is still underused in the field of organic semiconductors. , Pico-to-nanosecond exploration makes also QENS a method of choice to validate MD models and simulations as well as to establish the usefulness of their associated force field development. ,, The strength of QENS also stems from the neutron sensitivity to light elements. Neutron interaction with hydrogen atoms dominates the incoherent neutron signal as hydrogen exhibits the strongest incoherent neutron scattering cross section.…”

“…Neutron interaction with hydrogen atoms dominates the incoherent neutron signal as hydrogen exhibits the strongest incoherent neutron scattering cross section. We demonstrated the usefulness of QENS and other neutron spectroscopy techniques as a tool to study the dynamics of organic semiconductors for different applications, e.g., OSCs, − ,,, OFETs, OECTs, and hydrogen production. − In particular, we used a combined approach of neutron spectroscopy and MD simulations to study the dynamics of poly­(3-hexylthiophene) (P3HT) and poly­(3-octylthiophene) (P3OT)-conjugated polymers, followed by an extensive investigation of the local and vibrational dynamics of P3HT under its two regioregular (RR) and regiorandom (RRa) forms …”