Visualisation of individual dopants in a conjugated polymer: sub-nanometre 3D spatial distribution and correlation with electrical properties
Artikel i vetenskaplig tidskrift, 2022

While molecular doping is ubiquitous in all branches of organic electronics, little is known about the spatial distribution of dopants, especially at molecular length scales. Moreover, a homogeneous distribution is often assumed when simulating transport properties of these materials, even though the distribution is expected to be inhomogeneous. In this study, electron tomography is used to determine the position of individual molybdenum dithiolene complexes and their three-dimensional distribution in a semiconducting polymer at the sub-nanometre scale. A heterogeneous distribution is observed, the characteristics of which depend on the dopant concentration. At 5 mol% of the molybdenum dithiolene complex, the majority of the dopant species are present as isolated molecules or small clusters up to five molecules. At 20 mol% dopant concentration and higher, the dopant species form larger nanoclusters with elongated shapes. Even in case of these larger clusters, each individual dopant species is still in contact with the surrounding polymer. The electrical conductivity first strongly increases with dopant concentration and then slightly decreases for the most highly doped samples, even though no large aggregates can be observed. The decreased conductivity is instead attributed to the increased energetic disorder and lower probability of electron transfer that originates from the increased size and size variation in dopant clusters. This study highlights the importance of detailed information concerning the dopant spatial distribution at the sub-nanometre scale in three dimensions within the organic semiconductor host. The information acquired using electron tomography may facilitate more accurate simulations of charge transport in doped organic semiconductors.

Författare

Gustav Persson

Chalmers, Fysik, Nano- och biofysik

Emmy Järsvall

Chalmers, Kemi och kemiteknik, Tillämpad kemi

Magnus Röding

RISE Research Institutes of Sweden

Chalmers, Matematiska vetenskaper, Tillämpad matematik och statistik

Renee Kroon

Linköpings universitet

Chalmers, Kemi och kemiteknik, Tillämpad kemi

Yadong Zhang

University of Colorado at Boulder

Georgia Institute of Technology

Stephen Barlow

University of Colorado at Boulder

Georgia Institute of Technology

Seth R. Marder

Georgia Institute of Technology

University of Colorado at Boulder

Christian Müller

Chalmers, Kemi och kemiteknik, Tillämpad kemi

Eva Olsson

Chalmers, Fysik, Nano- och biofysik

Nanoscale

2040-3364 (ISSN) 2040-3372 (eISSN)

Vol. 14 41 15404-15413

Dubbel Dopning av Halvledande Polymerer

Vetenskapsrådet (VR) (2018-03824), 2018-01-01 -- 2021-12-31.

Ämneskategorier

Oorganisk kemi

Fysikalisk kemi

Den kondenserade materiens fysik

Infrastruktur

Chalmers materialanalyslaboratorium

DOI

10.1039/d2nr03554e

Mer information

Senast uppdaterat

2024-03-07