Natural optical activity as the origin of the large chiroptical properties in π-conjugated polymer thin films

DOI: 10.1038/s41467-020-19951-y

Authors: Jessica Wade (Imperial College London) , James N. Hilfiker (J.A. Woollam Co. Inc) , Jochen R. Brandt (Imperial College London) , Letizia Liirò-Peluso (University of Nottingham) , Li Wan (Imperial College London) , Xingyuan Shi (Imperial College London) , Francesco Salerno (Imperial College London) , Seán T. J. Ryan (Imperial College London) , Stefan Schöche (J.A. Woollam Co. Inc) , Oriol Arteaga (Universitat de Barcelona) , Tamas Javorfi (Diamond Light Source) , Giuliano Siligardi (Diamond Light Source) , Cheng Wang (Advanced Light Source) , David B. Amabilino (University of Nottingham) , Peter H. Beton (University of Nottingham) , Alasdair J. Campbell (Imperial College London) , Matthew J. Fuchter (Imperial College London)
Co-authored by industrial partner: Yes

Type: Journal Paper
Journal: Nature Communications , VOL 11

State: Published (Approved)
Published: December 2020
Diamond Proposal Number(s): 20376 , 21822

Abstract: Polymer thin films that emit and absorb circularly polarised light have been demonstrated with the promise of achieving important technological advances; from efficient, high-performance displays, to 3D imaging and all-organic spintronic devices. However, the origin of the large chiroptical effects in such films has, until now, remained elusive. We investigate the emergence of such phenomena in achiral polymers blended with a chiral small-molecule additive (1-aza[6]helicene) and intrinsically chiral-sidechain polymers using a combination of spectroscopic methods and structural probes. We show that – under conditions relevant for device fabrication – the large chiroptical effects are caused by magneto-electric coupling (natural optical activity), not structural chirality as previously assumed, and may occur because of local order in a cylinder blue phase-type organisation. This disruptive mechanistic insight into chiral polymer thin films will offer new approaches towards chiroptical materials development after almost three decades of research in this area.

Journal Keywords: Circular dichroism; Electronic devices; Optical physics; Polymers

Subject Areas: Materials, Physics


Instruments: B23-Circular Dichroism

Documents:
s41467-020-19951-y.pdf

Discipline Tags:

Material Sciences Polymer Science Physics Electronics Soft condensed matter physics Surfaces interfaces and thin films

Technical Tags:

Spectroscopy Circular Dichroism (CD)