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Conjugated polymers (CPs) are widely used in various domains of organic electronics. However, the performance of organic electronic devices can be variable due to the lack of precise predictive control over the polymer microstructure. While the chemical structure of CPs is important, CP microstructure also plays an important role in determining the charge-transport, optical and mechanical properties suitable for a target device. Understanding the interplay between CP microstructure and the resulting properties, as well as predicting and targeting specific polymer morphologies, would allow current comprehension of organic electronic device performance to be improved and potentially enable more facile device optimization and fabrication. In this Feature Article, we highlight the importance of investigating CP microstructure, discuss previous developments in the field, and provide an overview of the key aspects of the CP microstructure-property relationship, carried out in our group over recent years. [ABSTRACT FROM AUTHOR]

Atomic layer deposition (ALD) is a remarkable synthesis tool due to the vast array of materials that can be deposited and the complexity of structures that can be designed. The low-temperature layer-by-layer approach even allows organic and inorganic components to be combined as hybrid or composite materials. The technique is then called molecular layer deposition (MLD). This opens the door for deposition of advanced optical materials using highly absorbing aromatic molecules. Unfortunately, most large aromatic molecules are difficult to sublime or have insufficient reactivity. This is a major barrier for ALD when designing with the use of organic components for dye-sensitized solar cells, luminescence, visible light photochemistry, chemical sensors and organic electronics. In this work, we introduce a well-known orange dye molecule, quinizarin. This molecule has a large conjugated aromatic system with strong absorption of visible light and shows strong luminescence both in solutions and as a complex together with aluminium ions. Interestingly, quinizarin also shows surprisingly good properties for film deposition due to reactive –OH groups and low sublimation temperature (130 °C). Strongly coloured pink hybrid films were deposited with trimethylaluminium and quinizarin at 175 °C with a growth rate of 0.28 nm per cycle. These films were not luminescent although their optical absorption spectra are similar to those of the corresponding solution. An attempt was made to dilute quinizarin through partial replacement with pentaerythritol as a multilayer structure or simultaneous co-pulsing, although this also did not produce luminescent films. The low sublimation temperature, good reactivity and large conjugated system of quinizarin open the way for exploration of solid-state hybrid and organic films based on this molecule along many different technological pathways. [ABSTRACT FROM AUTHOR]

Diketopyrrolopyrrole (DPP) derivatives have been widely used as the electron-withdrawing unit to construct donor–acceptor (D–A) conjugated systems in organic electronics. The 3,6-position flanking aromatic rings of DPP could strongly influence the optoelectronic properties of DPP-based materials. In this study, a stepwise synthesis strategy was used to prepare monofluorinated and difluorinated dithienyl-DPP. The single crystal of the difluorinated model compound was also obtained. Three polymers based on bithiophene donor and dithienyl-DPP acceptor with different fluorinated positions were synthesized. And preliminary investigations of the influence of fluorination on the optoelectronic properties were performed. [ABSTRACT FROM AUTHOR]

Arsole-derived conjugated polymers are a relatively new class of materials in the field of organic electronics. Herein, we report the synthesis of two new donor polymers containing fused dithieno[3,2-b:2′,3′-d]arsole units and report their application in bulk heterojunction solar cells for the first time. Devices based upon blends with PC71BM display high open circuit voltages around 0.9 V and demonstrate power conversion efficiencies around 4%. [ABSTRACT FROM AUTHOR]

Pyridine-based materials have seen widespread attention for the development of n-type organic materials. In recent years, the incorporation of main-group elements has also explored significant advantages for the development and tunability of organic conjugated materials. The unique chemical and electronic structure of main-group elements has led to several enhancements in conventional organic materials. This Feature article highlights recent main-group based pyridine materials by discussing property enhancements and application in organic electronics. [ABSTRACT FROM AUTHOR]

Water/alcohol soluble conjugated polymers (WSCPs), which can be processed from water/alcohol and other polar solvents, are suitable for the solution processing of multi-layer organic electronic devices. By using a thin layer WSCP as the cathode interfacial material, the resulting polymer light-emitting diodes (PLEDs) and polymer solar cells (PSCs) exhibited significant enhancements in their device performances. In this Feature Article, the authors aim to introduce a brief review of the recent developments and applications of WSCPs in highly efficient multi-layer solution processed PLEDs and PSCs. [ABSTRACT FROM AUTHOR]

This tutorial reviewdescribes an atomistic simulation approach to studies of dynamics of charge transport in π-conjugated molecular or polymer based materials. The approach, which is termed electron–lattice dynamics, is based on the Ehrenfest theorem and includes nonadiabatic transport processes. The equations of motion for both the electrons and the nuclei are solved simultaneously using a Runge–Kutta method. We show that for ideal systems without disorder and thermal fluctuations in the electronic coupling between the constituent elements that the electron transport can be described as an adiabatic polaron drift process. In the presence of thermal fluctuations caused by, e.g., phenyl ring torsions along a poly(paraphenylene vinylene) chain, there are extensive variations in the electronic coupling along the polymer chain which results in nonadiabatic hopping transport. [ABSTRACT FROM AUTHOR]

New donor–acceptor alternating conjugated polymers were synthesized and characterized. Among them, PCPBBTexhibited a band-gap of 1.01 eV and ambipolar characteristics with μh= 7.1 × 10−4cm2V−1s−1and μe= 3.3 × 10−3cm2V−1s−1. [ABSTRACT FROM AUTHOR]