Silicon phthalocyanines (SiPcs) are a class of conjugated, planar molecule that have recently been investigated for use in organic photovoltaics (OPVs), organic light‐emitting diodes (OLEDs), and organic thin‐film transistors (OTFTs) due to their variable structure and ease of synthesis. Bottom‐gate, bottom‐contact OTFTs with four SiPc derivatives used as the semiconducting layers are prepared using physical vapor deposition. Devices using bis(pentafluorophenoxy) silicon phthalocyanine (F10‐SiPc) deposited on 140 °C substrates demonstrate electron field‐effect mobilities (μ) of up to 0.54 cm2 V−1 s−1, among the best currently reported for N‐type phthalocyanine‐based transistors. All materials show dramatic changes in charge transport when characterized under vacuum (P < 0.1 Pa) compared to in air at atmospheric pressure, typically switching from electron majority charge carriers to holes, with the change dependent on material structure and energetics. F10‐SiPc is close to balanced ambipolar in air, with μ around 5 × 10−3 cm2 V−1 s−1 for both holes and electrons. These results demonstrate SiPcs' potential as N‐type semiconductors in OTFTs as well as their adjustable charge transport as affected by operation environment.

This study illustrates the use of an N-type semiconductor, in both temperature and DNA sensors and further elucidates the mechanism of DNA sensing in OTFTs.

chemical and physical properties, including high mechanical strength, flexi bility, and unique optical and electrical properties. [1,2] The flexibility and stretch ability of carbon nanotubes, combined with their potential for comparable elec trical performance to traditional rigid materials (such as polysilicon and metal oxides) makes them particularly attractive for applications in wearable electronics, prosthetics, and flexible and printed elec tronics. [3] Their capacity for high charge carrier mobilities, [4] combined with solu tion processability, has resulted in the incorporation of SWNTs into photovol taics, [5] field effect transistors, [6] chem ical and biological sensors, [7][8][9] logic circuits, [10,11] and infrared photodetectors for telecommunications. [12] The structural polydispersity of as synthesized SWNTs, both in atomic struc ture and length, remains a major issue hindering widespread applications of these materials into electronics devices. [13] While some synthetic control over the diameter distribution can be achieved, all common techniques produce a dis tribution of chiralities and a mixture of both metallic and semiconducting nano tubes. [14] These mixtures are normally comprised of a ratio of ≈2:1 semiconducting SWNTs (scSWNTs) to metallic SWNTs (mSWNTs), in addition to the retention of impurities such as catalyst particles and amorphous carbon. This disparity in terms of electrical properties is not suitable for organic elec tronic devices, as mSWNTs can act as percolating or directly bridging paths that electrically short SWNT transistors, making the isolation of pure scSWNTs from a raw mixture of the utmost importance. [15] Additionally, SWNTs have poor solu bility and require the introduction of ancillary dispersants to properly exfoliate tube bundles to allow for the fabrication of uniform networks.Significant progress in the dispersion and separation of SWNTs according to electronic character, [16] chirality, [17] diameter, [18] or length [19] has been made over the past two decades. Density gradient ultracentrifugation, [20] gel chromatography, [21] DNA wrapping combined with ion The realization of organic thin film transistors (OTFTs) with performances that support low-cost and large-area fabrication remains an important and challenging topic of investigation. The unique electrical properties of singlewalled carbon nanotubes (SWNTs) make them promising building blocks for next generation electronic devices. Significant advances in the enrichment of semiconducting SWNTs, particularly via π-conjugated polymers for purification and dispersal, have allowed the preparation of high-performance OTFTs on a small scale. The intimate interaction of the conjugated polymer with both SWNTs and the dielectric necessitates the investigation of a variety of conjugated polymer derivatives for device optimization. Here, the preparation of polymer-SWNT composites containing carbazole moieties, a monomer unit that has remained relatively overlooked for the dispersal of large-diameter semiconducting...

A series of metal phthalocyanine based organic thin film transistors were evaluated and their responses to changes in temperature and environmental was determined: the choice of central atom makes a difference.

Ultrapure semiconducting single-walled carbon nanotube (sc-SWNT) dispersions produced through conjugated polymer sorting are ideal candidates for the fabrication of solution-processed organic electronic devices on a commercial scale. Protocols for sorting and dispersing ultrapure sc-SWNTs with conjugated polymers for thin-film transistor (TFT) applications have been well refined. Conventional wisdom dictates that removal of excess unbound polymer through filtration or centrifugation is necessary to produce high-performance TFTs. However, this is time-consuming, wasteful, and resource-intensive. In this report, we challenge this paradigm and demonstrate that excess unbound polymer during semiconductor film fabrication is not necessarily detrimental to device performance. Over 1200 TFT devices were fabricated from 30 unique polymer-sorted SWNT dispersions, prepared using two different alternating copolymers. Detailed Raman spectroscopy, x-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) studies of the random-network semiconductor films demonstrated that a simple solvent rinse during TFT fabrication was sufficient to remove unbound polymer from the sc-SWNT films, thus eliminating laborious polymer removal before TFT fabrication. Furthermore, below a threshold polymer concentration, the presence of excess polymer during fabrication did not significantly impede TFT performance. Preeminent performance was achieved for devices prepared from native polymer-sorted SWNT dispersions containing the “original” amount of excess unbound polymer (immediately following enrichment). Lastly, we developed an open-source Machine Learning algorithm to quantitatively analyze AFM images of SWNT films for surface coverage, number of tubes, and tube alignment.

Due to their superlative electrical and mechanical properties, single-walled carbon nanotubes (SWNTs) are capable of expanding the current scope of electronic device applications. Advancements in the selective isolation and purification of semiconducting SWNTs through the use of conjugated polymers has allowed for incorporation of highquality SWNTs into solution-processed thin-film transistors (TFTs). In this study, we report an alternating copolymer based on fluorene and 2,5-dimethoxybenzene that is capable of selectively dispersing semiconducting SWNTs. The exceptional semiconductingSWNT purity (>99%) of the dispersion was confirmed by UV−vis and Raman spectroscopy, which exhibit negligible metallic SWNT features. TFTs fabricated with this polymer−SWNT complex exhibited maximum hole and electron mobilities of 19 and 7 cm 2 /V•s, respectively, with on/off ratios as high as 10 7 . Device fabrication parameters including silane surface treatment, removal of excess polymer, and SWNT dispersion concentration were investigated. Evaluation of hole and electron mobilities indicates that the presence of excess polymer in the polymer−SWNT dispersion did not adversely affect device performance. Atomic force microscopy measurements showed that our polymer−SWNT dispersions were capable of forming a complete percolation pathway between electrodes, with individual SWNTs exfoliated by the polymer.

N-type organic semiconductors are notoriously unstable in air, requiring the design of new materials that focuses on lowering their LUMO energy levels and enhancing their air stability in organic electronic devices such as organic thin-film transistors (OTFTs). Since the discovery of the notably air stable and high electron mobility polymer poly{[N,N′-bis (2-octyldodecyl)- naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5′-(2,29-bisthiophene)} (N2200), it has become a popular n-type semiconductor, with numerous materials being designed to mimic its structure. Although N2200 itself is well-studied, many of these comparable materials have not been sufficiently characterized to compare their air stability to N2200. To further the development of air stable and high mobility n-type organic semiconductors, N2200 was studied in organic thin film transistors alongside three N2200-based analogues as well as a recently developed polymer based on a (3E,7E)-3,7-bis(2-oxoindolin-3-ylidene)benzo[1,2-b:4,5-b′]difuran-2,6(3 H,7 H)-dione (IBDF) core. This IBDF polymer has demonstrated promising field-effect mobility and air stability in drop-cast OTFTs. While N2200 outperformed its analogues, the IBDF-based polymer displayed superior air and temperature stability compared to N2200. Overall, polymers with more heteroatoms displayed greater air stability. These findings will support the development of new air-stable materials, and further demonstrate the persistent need for the development of novel n-type semiconductors.

In article number https://doi.org/10.1002/aelm.201800539, Nicole A. Rice, Alex Adronov, Benoît Lessard, and co‐workers report a novel poly(carbazole‐co‐fluorene) conjugated polymer capable of producing highly enriched semiconducting single‐walled carbon nanotube (SWNT) composites. Organic thin film transistors prepared from this composite demonstrate superior mobility and on/off ratios compared to devices prepared from a commercially available polymer–SWNT dispersion. Operational hysteresis is almost completely removed by simple surface treatment with octyltrichlorosilane before depositing polymer–SWNT material.