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Emerging wearable devices would benefit from integrating ductile photovoltaic light-harvesting power sources. In this work, we report a small-molecule acceptor (SMA), also known as a non–fullerene acceptor (NFA), designed for stretchable organic solar cell (s-OSC) blends with large mechanical compliance and performance. Blends of the organosilane-functionalized SMA BTP-Si4 with the polymer donor PNTB6-Cl achieved a power conversion efficiency (PCE) of >16% and ultimate strain (ε_u) of >95%. Typical SMAs suppress OSC blend ductility, but the addition of BTP-Si4 enhances it. Although BTP-Si4 is less crystalline than other SMAs, it retains considerable electron mobility and is highly miscible with PNTB6-Cl and is essential for enhancing ε_u. Thus,s-OSCs with PCE > 14% and operating normally under various deformations (>80% PCE retention under an 80% strain) were demonstrated. Analysis of several SMA-polymer blends revealed general molecular structure–miscibility–stretchability relationships for designing ductile blends. 

Morphological diversity, phase separated to highly intermixed, is induced in low miscibility blendsviasolution vitrification through control of liquid state chain entanglements, enabling establishment of relevant structure/property relations and a diverse property set. 

Printable feedstocks that can produce lightweight, robust, and ductile structures with tunable and switchable conductivity are of considerable interest for numerous application spaces. Combining the specific properties of commodity thermoplastics with the unique electrical and redox properties of conducting polymers (CPs) presents new opportunities for the field of printed (bio)electronics. Here, we report on the direct ink write (DIW) printing of ink formulations based on polyaniline-dinonylnaphthalene sulfonic acid (PANI-DNNSA), which has been synthesized in bulk quantities (∼400 g). DNNSA imparts solubility to PANI up to 50 mg mL −1 , which allows the use of various additives to tune the rheological behavior of the inks without significantly compromising the electrical properties of the printed structures, which reach conductivities in the range of <10 −7 –10 0 S cm −1 as a function of ink formulation and post treatment used. Fumed silica (FS) and ultra-high molecular weight polystyrene (UHMW-PS) additives are leveraged to endow printability and shape retention to inks, as well as to compare the use of traditional rheological modifiers with commodity thermoplastics on CP feedstocks for tailored DIW printing. We show that the incorporation of UHMW-PS into these ink formulations is critical for obtaining high crack resistance in printed structures. This work serves as a guide for future ink designs of CPs with commodity thermoplastics and their subsequent DIW printing to yield conductive architectures and devices for various applications. 

Organic semiconducting small molecules have attracted increasing interest over the last decades because of their versatile, tunable optoelectronic properties and, e.g. , the ease they can be purified compared to polymeric systems. Hence, over the past few decades, a large number of small molecules, such as acenes and thiophenes, have been explored for use in semiconducting devices such as thin-film transistors. However, many of these materials can adopt various molecular arrangements, producing polymorphic structures. As a result, the same material can display vastly different optoelectronic properties. This can, in many cases, lead to a large spread of device performances. Hence, it is critical to establish knowledge- and characterization libraries towards relevant structure/processing/performance interrelations to further advance this interesting class of materials and to open new application platforms. Here, we discuss processing strategies and methodologies that allow the control and assessment of polymorph formation in semiconducting small molecules using 5,11-bis(triethylsilylethynyl)anthradithiophene (TES ADT) as a model material system. We revise how a window into the complex phase behavior of semiconducting small molecules can be obtained, how specific polymorphs can be induced, and how post-deposition treatments can be exploited. Moreover, we illustrate pathways towards patterned structures as needed to fully exploit the touted potential of this interesting class of semiconductors. 

Abstract Functional macromolecular materials promise to enable important improvements in many aspects of everyday life, including for energy applications, novel electronics systems, or wearable health care products. In contrast to widely‐used commodity plastics such as polyolefins, polyamides, or polyesters, it, however, remains challenging to advance detailed insights into the interrelation of structure and performance for functional polymers, limiting progress. The reason is that the macroscopic properties of such polymers often depend on local chain arrangements rather than long‐range order only. Here, it is demonstrated on the example of the well‐investigated ferroelectric poly(vinylidene fluoride) (PVDF) that modern nuclear magnetic resonance (NMR) spectroscopy enables thequantitativeanalysis of the complex solid‐state structure of this polymer, providing unprecedented insight. The precise fractions of chain segments of different conformations are revealed, as well as their spatial distributions with respect to each other. Thereby, a significant population of short‐range ordered chain segments is identified, a large fraction of which in close proximity to defects and disordered segments. Unsurprisingly, different environments lead to different structural dynamics — collectively showing that characterizing local order/disorder and their dynamics is imperative to accurately describe the properties of functional polymers such as PVDF.