Establishing Self‐Dopant Design Principles from Structure–Function Relationships in Self‐n‐Doped Perylene Diimide Organic Semiconductors. Issue 42 (20th September 2022)

• Record Type: Journal Article
• Authors: Powell, Daniel; Zhang, Xueqiao; Nwachukwu, Chideraa I.; Miller, Edwin J.; Hansen, Kameron R.; Flannery, Laura; Ogle, Jonathan; Berzansky, Alex; Labram, John G.; Roberts, Andrew G.; Whittaker‐Brooks, Luisa
• Is Part Of: Advanced materials. Volume 34:Issue 42(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-09-20
• Subjects: charge‐carrier mobility -- morphology -- organic semiconductors -- self‐doping -- spin concentrations; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.202204656
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: Self‐doping is a particular doping method that has been applied to a wide range of organic semiconductors. However, there is a lack of understanding regarding the relationship between dopant structure and function. A structurally diverse series of self‐n‐doped perylene diimides (PDIs) is investigated to study the impact of steric encumbrance, counterion selection, and dopant/PDI tether distance on functional parameters such as doping, stability, morphology, and charge‐carrier mobility. The studies show that self‐n‐doping is best enabled by the use of sterically encumbered ammoniums with short tethers and Lewis basic counterions. Additionally, water is found to inhibit doping, which concludes that thermal degradation is merely a phenomenological feature of certain dopants, and that residual solvent evaporation is the primary driver of thermally activated doping. In situ grazing‐incidence wide‐angle X‐ray scattering studies show that sample annealing increases the π–π stacking distance and shrinks grain boundaries for improved long‐range ordering. These features are then correlated to contactless carrier‐mobility measurements with time‐resolved microwave conductivity before and after thermal annealing. The collective relationships between structural features and functionality are finally used to establish explicit self‐n‐dopant design principles for the future design of materials with improved functionality. Abstract : A circumscribed set of design principles that relate structure to material observables is analyzed to disentangle the effects of how counterion, tether length, and steric encumbrance affect doping levels, thermal activation, and stability of self‐doped organic semiconductors.