The controlled functionalization of single-walled carbon nanotubes with luminescent sp3-defects has created the potential to employ them as quantum-light sources in the near-infrared. For that, it is crucial to control their spectral diversity. The emission wavelength is determined by the binding configuration of the defects rather than the molecular structure of the attached groups. However, current functionalization methods produce a variety of binding configurations and thus emission wavelengths. We introduce a simple reaction protocol for the creation of only one type of luminescent defect in polymer-sorted (6,5) nanotubes, which is more red-shifted and exhibits longer photoluminescence lifetimes than the commonly obtained binding configurations. We demonstrate single-photon emission at room temperature and expand this functionalization to other polymer-wrapped nanotubes with emission further in the near-infrared. As the selectivity of the reaction with various aniline derivatives depends on the presence of an organic base we propose nucleophilic addition as the reaction mechanism.

This paper brings together the concepts of molecular complexity and crowdsourcing. An exercise was done at Merck where 386 chemists voted on the molecular complexity (on a scale of 1-5) of 2681 molecules taken from various sources: public, licensed, and in-house. The meanComplexity of a molecule is the average over all votes for that molecule. As long as enough votes are cast per molecule, we find meanComplexity is quite easy to model with QSAR methods using only a handful of physical descriptors (e.g., number of chiral centers, number of unique topological torsions, a Wiener index, etc.). The high level of self-consistency of the model (cross-validated R(2) ∼0.88) is remarkable given that our chemists do not agree with each other strongly about the complexity of any given molecule. Thus, the power of crowdsourcing is clearly demonstrated in this case. The meanComplexity appears to be correlated with at least one metric of synthetic complexity from the literature derived in a different way and is correlated with values of process mass intensity (PMI) from the literature and from in-house studies. Complexity can be used to differentiate between in-house programs and to follow a program over time.

The controlled covalent functionalization of semiconducting single-walled carbon nanotubes (SWCNTs) with luminescent sp 3 defects leads to additional narrow and tunable photoluminescence features in the near-infrared and even enables single-photon emission at room temperature, thus strongly expanding their application potential. However, the successful integration of sp 3 -functionalized SWCNTs in optoelectronic devices with efficient defect state electroluminescence not only requires control over their emission properties but also a detailed understanding of the impact of functionalization on their electrical performance, especially in dense networks. Here, we demonstrate ambipolar, light-emitting field-effect transistors based on networks of pristine and functionalized polymer-sorted (6,5) SWCNTs. We investigate the influence of sp 3 defects on charge transport by employing electroluminescence and (chargemodulated) photoluminescence spectroscopy combined with temperature-dependent currentvoltage measurements. We find that sp 3 -functionalized SWCNTs actively participate in charge transport within the network as mobile carriers efficiently sample the sp 3 defects, which act as shallow trap states. While both hole and electron mobilities decrease with increasing degree of functionalization, the transistors remain fully operational, showing electroluminescence from the defect states that can be tuned by the defect density. KEYWORDS single-walled carbon nanotubes, covalent functionalization, sp 3 defects, electroluminescence, light-emitting field-effect transistors, charge modulation spectroscopy Supporting InformationRaman and absorption spectra of pristine and sp 3 -functionalized SWCNT dispersions, AFM image of a pristine SWCNT network, additional electrical characterization (transfer and output curves, linear mobilities, frequency-dependent capacitance) of pristine and sp 3 -functionalized SWCNT network FETs, EL spectra, voltage-and power-dependent PL spectra, estimation of excitation densities in EL and PL measurements, schematic setup for CMPL spectroscopy, additional voltage-and frequency-dependent CMPL spectra, calculation of trap densities from subthreshold swings, schematic device layout and details for gated four-point probe measurements, temperaturedependent carrier mobilities. PDF

The functionalization of semiconducting single-wall carbon nanotubes (SWCNTs) with luminescent sp 3 defects creates red-shifted emission features in the near-infrared and boosts their photoluminescence quantum yields (PLQYs). While multiple synthetic routes for the selective introduction of sp 3 defects have been developed, a convenient metric to precisely quantify the number of defects on a SWCNT lattice is not available. Here, we present a direct and simple quantification protocol based on a linear correlation of the integrated Raman D/G + signal ratios and defect densities as extracted from PLQY measurements. Corroborated by a statistical analysis of single-nanotube emission spectra at cryogenic temperature, this method enables the quantitative evaluation of sp 3 defect densities in (6,5) SWCNTs with an error of ±3 defects per micrometer and the determination of oscillator strengths for different defect types. The developed protocol requires only standard Raman spectroscopy and is independent of the defect configuration, dispersion solvent, and nanotube length.

Efficient and controlled charge transport in networks of semiconducting single-walled carbon nanotubes is the basis for their application in electronic devices, especially in field-effect transistors and thermoelectrics. The recent advances in selective growth, purification, and sorting of semiconducting and even monochiral carbon nanotubes have enabled field-effect transistors with high carrier mobilities and on/off current ratios that were impossible a few years ago. They have also allowed researchers to examine the microscopic interplay of parameters such as nanotube length, density, diameter distribution, carrier density, intentional and unintentional defects, dielectric environment, etc., and their impact on the macroscopic charge transport properties in a rational and reproducible manner. This review discusses various models that are considered for charge transport in nanotube networks and the experimental methods to characterize and investigate transport beyond simple conductivity or transistor measurements. Static and dynamic absorption, photoluminescence and electroluminescence spectroscopy, as well as scanning probe techniques (e.g., conductive atomic force microscopy, Kelvin probe force microscopy), and their unique insights in the distribution of charge carriers in a given nanotube network and the resulting current pathways will be introduced. Finally, recommendations for further optimization of nanotube network devices and a list of remaining challenges are provided.

The functionalization of single-walled carbon nanotubes (SWCNTs) with luminescent sp 3 defects has greatly improved their performance in applications such as quantum light sources and bioimaging. Here, we report the covalent functionalization of purified semiconducting SWCNTs with stable organic radicals (perchlorotriphenylmethyl, PTM) carrying a net spin. This model system allows us to use the near-infrared photoluminescence arising from the defect-localized exciton as a highly sensitive probe for the short-range interaction between the PTM radical and the SWCNT. Our results point toward an increased triplet exciton population due to radical-enhanced intersystem crossing, which could provide access to the elusive triplet manifold in SWCNTs. Furthermore, this simple synthetic route to spin-labeled defects could enable magnetic resonance studies complementary to in vivo fluorescence imaging with functionalized SWCNTs and facilitate the scalable fabrication of spintronic devices with magnetically switchable charge transport.

Solution-processed networks of semiconducting, single-walled carbon nanotubes (SWCNTs) have attracted considerable attention as materials for next-generation electronic devices and circuits. However, the impact of the SWCNT network composition on charge transport on a microscopic level remains an open and complex question. Here, we use charge-modulated absorption and photoluminescence spectroscopy to probe exclusively the mobile charge carriers in monochiral (6,5) and mixed SWCNT network field-effect transistors. Ground state bleaching and charge-induced trion absorption features, as well as exciton quenching are observed depending on applied voltage and modulation frequency. Through correlation of the modulated mobile carrier density and the optical response of the nanotubes, we find that charge transport in mixed SWCNT networks depends strongly on the diameter and thus bandgap of the individual species. Mobile charges are preferentially transported by small bandgap SWCNTs especially at low gate voltages, whereas large bandgap species only start to participate at higher carrier concentrations. Our results demonstrate the excellent suitability of modulation spectroscopy to investigate charge transport in nanotube network transistors and highlight the importance of SWCNT network composition for their performance.KEYWORDS single-walled carbon nanotubes, networks, charge transport, charge modulation spectroscopy, photoluminescence, trionSemiconducting single-walled carbon nanotubes (SWCNTs) have emerged as a promising material for future electronic applications as they combine high charge carrier mobilities with mechanical flexibility and solution-processability. 1, 2 Stimulated by the major progress in sorting techniques such as gel chromatography, 3, 4 density gradient ultracentrifugation, 5 aqueous two-phase separation, 6 and polymer-wrapping, 7-9 the reproducible fabrication of highperformance field-effect transistors (FETs) and circuits based on networks of purely semiconducting SWCNTs has become feasible. [10][11][12][13][14][15][16] Nonetheless, charge transport in nanotube networks is not yet fully understood especially regarding mixed networks of nanotube species with varying compositions. 17, 18 A detailed understanding of the fundamental transport parameters is necessary to further optimize effective carrier mobilities for competitive network devices at a minimum cost for purification.Charge transport in semiconductors is commonly studied through temperature-dependent measurements of conductivities and carrier mobilities. 17, 19-21 However, these techniques cannot distinguish between different SWCNT species and thus are not suitable to examine the chirality-dependent contributions to the macroscopic device performance. Given the high sensitivity of SWCNT absorption and emission features to charge carriers, which was shown in several studies, 22-25 electro-optical methods could provide additional and even chiralityspecific insights. For example, based on the analysis of the E11 absorption band change of...

Biosensors are expected to revolutionize disease management through provision of low-cost diagnostic platforms for molecular and pathogenic detection with high sensitivity and short response time. In this context, there has been an everincreasing interest in using electrolyte-gated field-effect transistors (EG-FETs) for biosensing applications owing to their expanding potential of being employed for label-free detection of a broad range of biomarkers with high selectivity and sensitivity while operating at sub-volt working potentials. Although organic semiconductors have been widely utilized as the channel in EG-FETs, primarily due to their compatibility with cost-effective lowtemperature solution-processing fabrication techniques, alternative carbon-based platforms have the potential to provide similar advantages with improved electronic performances. Here, we propose the use of inkjet-printed polymer-wrapped monochiral singlewalled carbon nanotubes (s-SWCNTs) for the channel of EG-FETs in an aqueous environment. In particular, we show that our EG-CNTFETs require only an hour of stabilization before producing a highly stable response suitable for biosensing, with a drastic time reduction with respect to the most exploited organic semiconductor for biosensors. As a proof-of-principle, we successfully employed our water-gated device to detect the well-known biotin−streptavidin binding event.