Standardized combination antibiotic therapy was moderately effective in treating M. abscessus lung disease. However, frequent adverse reactions and the potential for long-duration hospitalization are important problems that remain to be solved.

During the past decade, various new types of organic nonlinear optical crystals have been developed to overcome the benchmark stilbazolium DAST (4-(4-(N,N-dimethylamino)styryl)-1-methylpyridinium 4-methylbenzenesulfonate) crystal. Here, we review the acentric core structures used in recently developed organic nonlinear optical crystals exhibiting high macroscopic second-order optical nonlinearity, along with their supramolecular interactions and THz applications. The nonlinear optical acentric core structures such as neutral CLP (configurationally locked polyene based on phenyltriene), ionic pyridiniumbased N-alkyl DAS (4-(4-(N,N-dimethylamino)styryl)-1-alkylpyridinium benzenesulfonate) and N-phenyl DAP ((4-(N,N-dimethylamino)styryl)-1-phenylpyridinium hexafluorophosphate), ionic quinolinium-based HMQ (2-(4-hydroxy-3-methoxystyryl)-1-methylquinolinium benzenesulfonate) and OHQ (2-(4hydroxystyryl)-1-methylquinolinium benzenesulfonate) and benzoindolium-based DBI(2-(4-(dimethylamino)styryl)-1,3,3-trimethyl-3H-benzoijg]indolium iodide) exhibit comparable or enhanced physical properties compared to DAST crystals. Organic crystals introducing an identical acentric core structure often exhibit similar molecular alignment features with analogous supramolecular interactions. We also discuss the nonlinear optical properties and potential applications of these materials, in particular their very promising THz photonic applications.

The high-power broadband terahertz (THz) generator is an essential tool for a wide range of THz applications. Here, we present a novel highly efficient electro-optic quinolinium single crystal for THz wave generation. For obtaining intense and broadband THz waves by optical-to-THz frequency conversion, a quinolinium crystal was developed to fulfill all the requirements, which are in general extremely difficult to maintain simultaneously in a single medium, such as a large macroscopic electro-optic response and excellent crystal characteristics including a large crystal size with desired facets, good environmental stability, high optical quality, wide transparency range, and controllable crystal thickness. Compared to the benchmark inorganic and organic crystals, the new quinolinium crystal possesses excellent crystal properties and THz generation characteristics with broader THz spectral coverage and higher THz conversion efficiency at the technologically important pump wavelength of 800 nm. Therefore, the quinolinium crystal offers great potential for efficient and gap-free broadband THz wave generation.

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Magnetic colloidal nanocrystals tend to aggregate in solution because of magnetic dipolar interactions. A diblock copolymer was used as a stabilizer to limit these effects, especially those leading to aggregation in solution. Cobalt nanoparticles have been synthesized within inverse micelles of polystyrene-block-poly(2-vinylpyridine) copolymer in toluene by the pyrolysis of dicobalt octacarbonyl at 115°C. The nanoparticle structure at different reaction times was investigated using transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FT-IR). At early reaction stages, the nanoparticles were found to be noncrystalline from TEM, and FT-IR showed that the precursor was only partially decomposed. After 15 min of reaction, the nanoparticles became crystalline, forming chains due to magnetic interactions. The noncrystalline nanoparticles could be crystallized upon heating to 420°C on grids in the transmission electron microscope. This produced nearly monodisperse single nanocrystals inside each micelle, with limited aggregation, but such annealing led to the degradation of the polymer.Magnetic colloidal or micellar chemically synthesized monodisperse nanoparticles (NPs) or nanocrystals (NCs) have recently been the subject of numerous studies because of their possible implementation into future ultrahigh density (>100 Gbit/in 2 ) patterned magnetic media (PMM) 1-5 or magnetoresistive devices, 6-8 among other applications. It is now well established that such NCs can act as single bits for information storage. 3,9 However, there are two major difficulties that should be overcome if PMM with such NCs is ever to be achieved. First, monodispersity (reduced standard deviation of the NCs population size distribution σ below 10%) has to be reached. This can be achieved by temporally separating the nucleation and growth stages involved in the synthesis of the NCs 10 or by focusing the size distribution by adjusting the precursor concentration during the synthesis. 11 Because monodisperse particles are difficult to synthesize in practical situations, postsynthesis operations such as filtering and/or size-selective precipitation 12 are used, limiting the yield of the synthesis. Furthermore, chemically synthesized magnetic colloidal NCs, each consisting of a crystalline core surrounded by small organic molecule surfactants, have, in addition to van der Waals interactions, an attractive magnetic dipole 13 that tends to cause these to aggregate in solution. Such a lack of stability in solution causes poor postsynthesis processing ability. It is possible to obtain soft magnetic or paramagnetic NCs and recrystallize them to harder magnetic phases. This method was introduced by Sun et al. with the transition from disordered fcc-FePt to fct-FePt at 560°C. 3 A similar idea was employed with cobalt (lower anisotropy than FePt but a higher magnetic moment per NC): -Co f hcp-Co at 300°C 5 or fcc-Co at 500°C. 14 Yet, there is still no real control over the interparticle distance, and this can give rise to magnet...

For terahertz (THz) wave generators based on organic electrooptic crystals, their intrinsic phonon modes are playing an essential role in THz generation characteristics. Here, this study proposes an effective design strategy for THz phonon mode engineering of organic electrooptic salt crystals for efficient optical‐to‐THz frequency conversion. To reduce phonon‐mode intensity, strongly electronegative trifluoromethyl group acting as strong hydrogen‐bond acceptor is incorporated into molecular anions. New 2‐(4‐hydroxy‐3‐methoxystyryl)‐1‐methylquinolinium 4‐(trifluoromethyl)benzenesulfonate (HMQ‐4TFS) crystals exhibit a relatively small absorption coefficient in the THz spectral range between 0.5 and 4 THz, which is attributed to suppressed molecular vibrations due to strong hydrogen bonds involving the 4TFS anion. In addition, HMQ‐4TFS crystals possess a very large macroscopic optical nonlinearity, comparable (or even higher) to benchmark stilbazolium crystals. Based on the low‐intensity THz phonon modes and the large optical nonlinearity, a 0.37 mm thick HMQ‐4TFS crystal pumped with 150 fs infrared laser pulses facilitates very efficient THz wave generation by optical rectification, delivering 23 times higher peak‐to‐peak THz electric field than the widely used standard inorganic ZnTe crystal (1.0 mm thick) and a broader spectral bandwidth. Therefore, strongly electronegative groups introduced into molecular salt electrooptic crystals provide a very promising design strategy of THz phonon mode engineering for developing intense broadband THz sources.

We show that the organic electro-optic crystal HMQ-TMS [2-(4-hydroxy-3-methoxystyryl)-1-methylquinolinium 2,4,6-trimethylbenzenesulfonate] has favorable properties for the parametric generation of THz waves in a collinear type-0 phase-matching scheme, i.e., a low absorption coefficient at wavelengths from 800 to 1500 nm (α < 1.5 cm −1), a relatively low absorption coefficient at frequencies from 0.3 to 1.5 THz (α < 100 cm −1), and a large coherence length in these spectral ranges (l c > 0.5 mm). We demonstrate efficient generation of broadband THz pulses through optical rectification of sub-picosecond laser pulses in a 0.2 mm thick HMQ-TMS crystal at the wavelength of 1000 nm. The energy conversion efficiency achieved in this crystal was 41 times higher than the one achieved in a 0.3 mm thick GaP crystal, which is an often used material for collinearly phase-matched THz generation at this laser wavelength. The peak amplitudes of the THz signal obtained with the HMQ-TMS crystal were 5.4 times larger in the time-domain and 7.1 times larger in the frequency-domain than the ones obtained with the GaP crystal.

This study reports a new nonfullerene electron transporting material (ETM) based on naphthalene diimide (NDI) small molecules for use in high-performance perovskite solar cells (PSCs). These solar cells simultaneously achieve high power conversion efficiency (PCE) of over 20% and long-term stability. New NDI-ID (N,N′-Bis(1-indanyl)naphthalene-1,4,5,8-tetracarboxylic diimide) consisting of an N-substituted indane group having simultaneous alicyclic and aromatic characteristics is synthesized by a low-cost, one-step reaction, and facile purification method. The partially flexible characteristics of an alicyclic cyclopentene group on indane groups open the possibility of lowtemperature solution processing. The conformational rigidity and aromaticity of phenyl and alicyclic groups contribute to high temporal stability by strong secondary bonds. NDI-ID has herringbone packed semiconducting NDI cores that exhibit up to 0.2 cm 2 V −1 s −1 electron mobility in field effect transistors. The inverted PSCs based on CH(NH 2 ) 2 PbI 3-x Br x with NDI-ID ETM exhibit very high PCEs of up to 20.2%, which is better than that of widely used PCBM (phenyl-C61-butyric acid methyl ester) ETM-based PSCs. Moreover, NDI-IDbased PSCs exhibit very high long-term temporal stability, retaining 90% of the initial PCE after 500 h at 100 °C with 1 sun illumination without encapsulation. Therefore, NDI-ID is a promising ETM for highly efficient, stable PSCs.