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Chlorinated solvents are commonly used to process organic semiconductor devices but have several negative environmental impacts. The choice of processing solvent significantly affects the layer microstructure and device performance, so replacing chlorinated solvents is non-trivial. Herein, we investigate the microstructural and electron-transporting properties of small-molecule non-fullerene acceptor (NFA) films and transistors processed from various non-chlorinated solvents. We show that the ensuing NFA transistors exhibit improved layer morphology, crystallinity, and electron mobility superior to those processed from chlorinated solvents. Our work highlights using non-chlorinated solvents to optimise charge transport in organic semiconductors and their devices while mitigating adverse environmental effects. [ABSTRACT FROM AUTHOR]

The high photoluminescence efficiency, color purity, extended gamut, and solution processability make low‐dimensional hybrid perovskites attractive for light‐emitting diode (PeLED) applications. However, controlling the microstructure of these materials to improve the device performance remains challenging. Here, the development of highly efficient green PeLEDs based on blends of the quasi‐2D (q2D) perovskite, PEA2Cs4Pb5Br16, and the wide bandgap organic semiconductor 2,7 dioctyl[1] benzothieno[3,2‐b]benzothiophene (C8‐BTBT) is reported. The presence of C8‐BTBT enables the formation of single‐crystal‐like q2D PEA2Cs4Pb5Br16 domains that are uniform and highly luminescent. Combining the PEA2Cs4Pb5Br16:C8‐BTBT with self‐assembled monolayers (SAMs) as hole‐injecting layers (HILs), yields green PeLEDs with greatly enhanced performance characteristics, including external quantum efficiency up to 18.6%, current efficiency up to 46.3 cd A−1, the luminance of 45 276 cd m−2, and improved operational stability compared to neat PeLEDs. The enhanced performance originates from multiple synergistic effects, including enhanced hole‐injection enabled by the SAM HILs, the single crystal‐like quality of the perovskite phase, and the reduced concentration of electronic defects. This work highlights perovskite:organic blends as promising systems for use in LEDs, while the use of SAM HILs creates new opportunities toward simpler and more stable PeLEDs. [ABSTRACT FROM AUTHOR]

Carrier transport properties of solution processed ultra thin (4 nm) zinc-tin oxide (ZTO) thin film transistor are investigated based on its transfer characteristics measured at the temperature ranging from 310K to 77K. As temperature decreases, the transfer curves show a parellel shift toward more postive voltages. The conduction mechanism of ultra-thin ZTO film and its connection to the density of band tail states have been substantiated by two approaches, including fitting logarithm drain current (log ID) to T-1/3 at 310K to 77K according to the two-dimensional Mott variable range hopping theory and the extraction of density of localized tail states through the energy distribution of trapped carrier density. The linear dependency of log ID vs. T-1/3 indicates that the dominant carrier transport mechanism in ZTO is the variable range hopping. The extracted value of density of tail states at the conduction band minimum is 4.75×1020 cm-3 eV-1 through the energy distribution of trapped carrier density. The high density of localized tail states in the ultra thin ZTO film is the key factor leading to the room-temperature hopping transport of carriers among localized tail states. [ABSTRACT FROM AUTHOR]

The article presents a study focusing on the effect of mechanical strain on lead sulfide (PbS) nanocrystal field-effect transistors' (FETs) electrical characteristics. Topics discussed include the use of ion gel as a gate dielectric in the study; the fabrication of FETs using polyethylene naphthalate (PEN); and the electron mobility reported in PbS FETs.

Metal oxide thin‐film transistors (TFTs) offer remarkable opportunities for applications in emerging transparent and flexible microelectronics. Unfortunately, their performance is hindered by limitations associated with parasitic effects, such as parasitic electrode overlap capacitances and high contact resistance, which can severely limit their dynamic behavior. Here, an innovative method is reported to fabricate coplanar self‐aligned‐gate (SAG) indium‐gallium‐zinc‐oxide (IGZO) transistors with engineered source/drain contacts. The manufacturing process starts with the deposition and patterning of a gate electrode/dielectric stack and its functionalization with an organic self‐assembled monolayer (SAM) as the surface energy modifier. A second gold (Au) electrode is subsequently deposited over the gate electrode stack. The overlapping region between the two electrodes is removed via self‐delamination under mild sonication, forming perfectly aligned coplanar Au‐Gate‐Au electrodes. Device fabrication is completed with the spin coating of the IGZO precursor, followed by rapid photonic curing. Replacing the gold source/drain contact with bimetallic electrodes such as Au/In and Au/ITO enables a reduction in contact resistance and improves the transistor performance remarkably without increasing manufacturing complexity. The method is highly scalable, robust, and applicable to other semiconductor materials. [ABSTRACT FROM AUTHOR]

Solution-processable poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is an important polymeric conductor used extensively in organic flexible, wearable, and stretchable optoelectronics. However, further enhancing its conductivity and long-term stability while maintaining its superb mechanical properties remains challenging. Here, a novel post-treatment approach to enhance the electrical properties and stability of sub-20-nm-thin PEDOT:PSS films processed from solution is introduced. The approach involves a sequential post-treatment with HNO 3 and CsCl, resulting in a remarkable enhancement of the electrical conductivity of PEDOT:PSS films to over 5500 S cm -1 , along with improved carrier mobility. The post-treated films exhibit remarkable air stability, retaining over 85% of their initial conductivity even after 270 days of storage. Various characterization techniques, including X-ray photoelectron spectroscopy, atomic force microscopy, Raman spectroscopy, Hall effect measurements, and grazing incidence wide angle X-ray scattering, coupled with density functional theory calculations, provide insights into the structural changes and interactions responsible for these improvements. To demonstrate the potential for practical applications, the ultrathin PEDOT:PSS films are connected to an inorganic light-emitting diode with a battery, showcasing their suitability as transparent electrodes. This work presents a promising approach for enhancing the electrical conductivity of PEDOT:PSS while offering a comprehensive understanding of the underlying mechanisms that can guide further advances., (© 2024 The Author(s). Advanced Materials published by Wiley‐VCH GmbH.)

Electronic doping in organic materials has remained an elusive concept for several decades. It drew considerable attention in the early days in the quest for organic materials with high electrical conductivity, paving the way for the pioneering work on pristine organic semiconductors (OSCs) and their eventual use in a plethora of applications. Despite this early trend, however, recent strides in the field of organic electronics have been made hand in hand with the development and use of dopants to the point that are now ubiquitous. Here, we give an overview of all important advances in the area of doping of organic semiconductors and their applications. We first review the relevant literature with particular focus on the physical processes involved, discussing established mechanisms but also newly proposed theories. We then continue with a comprehensive summary of the most widely studied dopants to date, placing particular emphasis on the chemical strategies toward the synthesis of molecules with improved functionality. The processing routes toward doped organic films and the important doping-processing-nanostructure relationships, are also discussed. We conclude the review by highlighting how doping can enhance the operating characteristics of various organic devices.