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This study reports the fabrication and performance of single‐crystal organic field‐effect transistors (SC‐OFETs) based on three 5,15‐bisaryl‐tetrabenzoporphyrin (BP) derivatives: C8Ph‐BP, C8Ph‐Ph‐BP, and Ph‐BP, where C8Ph and Ph are 4‐n‐octylphenyl and phenyl groups, respectively. These compounds are designed to investigate how meso‐substituted C8Ph and Ph groups affect molecular packing and charge transport properties of BP derivatives. X‐ray crystallography analysis confirms that all derivatives exhibit a herringbone packing structure. SC‐OFETs using single crystals of each derivative demonstrate maximum hole mobilities of 1.64 cm2 V−¹ s−¹ for C8Ph‐BP, 0.89 cm2 V−¹ s−¹ for C8Ph‐Ph‐BP, and 1.21 cm2 V−¹ s−¹ for Ph‐BP. The high mobility of C8Ph‐BP is attributed to its interdigitated parallel π‐stacking, enhanced by van der Waals interactions between n‐octyl groups. In contrast, Ph‐BP and C8Ph‐Ph‐BP show lower charge mobilities. This work demonstrates the influence of the n‐octyl and meso‐phenyl groups on the packing arrangements and the charge transport efficiency in SC‐OFETs, offering insights into optimizing organic semiconductors for high‐performance electronic applications. This study explores single‐crystal organic field‐effect transistors (SC‐OFETs) based on 5,15‐bisaryl‐tetrabenzoporphyrin derivatives. It highlights the impact of meso‐substituted groups on molecular packing and charge transport. Among the derivatives, C8Ph‐BP achieves the highest hole mobility (1.64 cm2 V−¹ s−¹) due to enhanced π‐stacking with interdigitated layer‐by‐layer structure, offering valuable insights into optimizing organic semiconductors for high‐performance electronics.

Organic single crystals (OSCs) offer a unique combination of both individual and collective properties of the employed molecules, but it remains highly challenging to achieve OSCs with both high mobilities and strong fluorescence emissions for their potential applications in multifunctional optoelectronics. Herein, we demonstrate the design and synthesis of two novel triphenylamine‐functionalized thienoacenes‐based organic semiconductors, 4,8‐distriphenylamineethynylbenzo[1,2‐b:4,5‐b′]dithiophene (4,8‐DTEBDT) and 2,6‐distriphenylamineethynylbenzo[1,2‐b:4,5‐b′]dithiophene (2,6‐DTEBDT), with high‐mobility and strong fluorescence emission. The two compounds show the maximum mobilities up to 0.25 and 0.06 cm2 V−1 s−1, the photoluminescence quantum yields (PLQYs) of 51% and 45%, and the small binding energies down to 55.13 and 58.79 meV. The excellent electrical and optical properties ensured the application of 4,8‐DTEBDT and 2,6‐DTEBDT single crystals in ultrasensitive UV phototransistors, achieving high photoresponsivity of 9.60 × 105 and 6.43 × 104 A W−1, and detectivity exceeding 5.68 × 1017 and 2.99 × 1016 Jones. Organic single crystals based on two novel triphenylamine‐functionalized thienoacene derivatives, 4,8‐DTEBDT and 2,6‐DTEBDT, with high mobilities up to 0.25 cm2 V−1 s−1 and the high PLQYs of 51% for ultrasensitive UV single‐crystal organic phototransistors, achieving high photoresponsivity of 9.60 × 105 A W−1, and ultrahigh detectivity exceeding 5.68 × 1017 Jones.

Mechanically responsive crystals are promising for actuators and microrobotics; however, achieving large reversible deformation with high durability remains challenging. Herein, A single‐component azobenzene crystal is reported to exhibit an abrupt and reversible stretching of over 8% along its long axis, driven by a thermally induced single‐crystal‐to‐single‐crystal phase transition. Single‐crystal X‐ray diffraction revealed a significant change in molecular packing distance along the long axis accompanied by the reorientation of CH–π interactions, leading to large macroscopic stretching/shrinking. Furthermore, visible light (435 nm) induced rapid, localized, and reversible stretching of the crystal via the photothermal effect, enabling the remote control of microparticle motion. This study reveals a rare combination of large anisotropic deformation, reversibility, and light responsiveness in a single‐component organic crystal, offering a new molecular platform for advancing micro‐energy conversion and soft robotics. Crystals of azobenzene compounds exhibit abrupt and reversible stretching and shrinking in response to thermal and photo stimulation. The single‐crystal‐to‐single‐crystal phase transition between two polymorphs involving reorientation of CH–π hydrogen interactions are demonstrated. Furthermore, the abrupt photoinduced stretching of the crystals is used to trigger microparticle transportation.

Thin film transistors (TFTs) are indispensable building blocks in any electronic device and play vital roles in switching, processing, and transmitting electronic information. TFT fabrication processes inherently require the sequential deposition of metal, semiconductor, and dielectric layers and so on, which makes it difficult to achieve reliable production of highly integrated devices. The integration issues are more apparent in organic TFTs (OTFTs), particularly for solution-processed organic semiconductors due to limits on which underlayers are compatible with the printing technologies. We demonstrate a ground-breaking methodology to integrate an active, semiconducting layer of OTFTs. In this method, a solution-processed, semiconducting membrane composed of few-molecular-layer–thick single-crystal organic semiconductors is exfoliated by water as a self-standing ultrathin membrane on the water surface and then transferred directly to any given underlayer. The ultrathin, semiconducting membrane preserves its original single crystallinity, resulting in excellent electronic properties with a high mobility up to 12 cm²·V−1·s−1. The ability to achieve transfer of wafer-scale single crystals with almost no deterioration of electrical properties means the present method is scalable. The demonstrations in this study show that the present transfer method can revolutionize printed electronics and constitute a key step forward in TFT fabrication processes.

Memristors proposed by Leon Chua provide a new type of memory device for novel neuromorphic computing applications. However, the approaching of distinct multi‐intermediate states for tunable switching dynamics, the controlling of conducting filaments (CFs) toward high device repeatability and reproducibility, and the ability for large‐scale preparation devices, remain full of challenges. Here, we show that vertical‐organic‐nanocrystal‐arrays (VONAs) could make a way toward the challenges. The perfect one‐dimensional structure of the VONAs could confine the CFs accurately with fine‐tune resistance states in a broad range of 103 ratios. The availability of large‐area VONAs makes the fabrication of large‐area crossbar memristor arrays facilely, and the analog switching characteristic of the memristors is to effectively imitate different kinds of synaptic plasticity, indicating their great potential in future applications. In this study, vertical‐organic‐nanocrystal‐arrays (VONAs) was developed to construct high‐performance memristors. The unique nanostructure of VONAs could confine conducting filaments accurately, showing fine resistance tuning in a broad ratio. The availability of large‐area VONAs makes the fabrication of large‐area crossbar memristor arrays facilely, and their analog switching characteristic is effective to imitate different kinds of synaptic plasticity, indicating their great potential in future applications.

Organic optoelectronics is an emerging field that exploits the unique properties of conjugated organic materials to develop new applications that require a combination of performance, low cost, light weight, and processability. For instance, disposable or wearable electronics, light-emitting diodes, smart tags, sensors, and solar cells all fall into this active area of research. Single crystals of conjugated organic molecules are, undoubtedly, the materials with the highest degree of order and purity among the variety of different forms of organic semiconductors. Electronic devices comprising these materials, such as single-crystal transistors and photoconductors developed during the last decade, are by far the best performers in terms of the fundamental parameters such as charge-carrier mobility, exciton diffusivity, concentration of defects, and operational stability. Extremely low density of defects and the resultant remarkable electrical characteristics of some of the organic single-crystal devices allow experimental access to the intrinsic charge transport properties not dominated by charge scattering and trapping. This enables basic studies of the physics of organic semiconductors, including examining the intrinsic structure-property relationship, thus providing a test bed for charge and energy transport theories. The goal of this issue of MRS Bulletin is to provide a broad overview of the state of the art of the field of organic semiconductor single-crystal materials, devices, and theory.

Organic single crystals are an established part of the emerging field of organic optoelectronics, because they provide an ideal platform for the studies of the intrinsic physical properties of organic semiconductors. As organic crystals have low melting temperatures and high vapor pressures and are soluble in numerous organic solvents, both solution and gas-phase methods can be used for crystal growth. The nature of the individual molecules and the interactions between molecules determine which growth method is preferred for particular materials. Organic semiconductors with very low decomposition or melting temperatures can be grown from solutions, whereas semiconductors with high vapor pressures can be grown using physical vapor transport methods. High-quality crystals can be obtained using both methods. Crystal growth and crystal engineering of multicomponent organic compounds are emerging fields that can provide a variety of new materials with different physical properties. The growth of large crystals from the melt by zone melting, the Bridgman, or the Czochralski methods has been used to produce stable materials used in wafer manufacturing or large scintillator detectors. In this article, single-crystal growth methods for organic semiconductors are discussed with the aim of preparing high-quality specimens for determination of the basic properties of organic semiconductors.

Photogating and electrical gating are key physical mechanisms in organic phototransistors (OPTs). However, most OPTs are based on thick and polycrystalline films, which leads to substantially low efficiency of both photogating and electrical gating and thus reduced photoresponse. Herein, high-performance OPTs based on few-layered organic single-crystalline heterojunctions are proposed and the obstacle of thick and polycrystalline films for photodetection is overcome. Because of the molecular scale thickness of the type I organic single-crystalline heterojunctions in OPTs, both photogating and electrical gating are highly efficient. By synergy of efficient photogating and electrical gating, key figures of merit of OPTs reach the highest among those based on planar heterojunctions so far as we know. The production of few-layered organic single-crystalline heterojunctions will provide a new type of advanced materials for various applications.

The organic single crystal of aniline-4-sulphonic acid (A4SA) was synthesized and grown by slow evaporation solution technique (SEST) using distilled water as a solvent. The lattice parameters of the grown crystal were confirmed by single-crystal X-ray diffraction analysis. The X-ray diffraction exposes that the A4SA crystal belongs to an orthorhombic system with space group Pca2 1 . Functional groups of A4SA crystal were confirmed by Fourier transform infrared (FTIR) and FT-Raman spectrum analyses. The optical quality of the grown crystal was identified by the UV-Visible NIR spectrum analysis. The grown crystal has good optical transmittance in the range of 300–900 nm. The photoconductivity analysis was carried out to calculate the photo and dark current values. Photoconductivity study indicates that A4SA crystal shows a negative photoconductivity nature. Intermolecular interactions of A4SA are executed by the Hirshfeld surface analysis. The chemical etching was investigated to calculate the etch pit density. Photoluminescence analysis for grown crystals is obtained. Thermogravimetric, differential thermogravimetric analysis and differential scanning calorimetry (TG, DTA, DSC) measurements investigate the thermal stability of a grown crystal. Vickers microhardness analysis was performed to study the mechanical properties of the material. The Nd:YAG laser, with a wavelength of 1064 nm, was used to examine the LDT analysis. It shows a good LDT value of 5.02 GW/cm 2 . The third-order non-linear susceptibility was measured and analysed by Z-scan technique using (He–Ne) laser of wavelength 632.8 nm.

A new organic single crystal of creatinine 4-aminobenzoate (C4AB) was successfully grown using a slow evaporation solution technique (SEST). The lattice parameters, crystalline perfection and hkl planes of the grown crystal were observed by SCXRD and powder XRD analysis. The surface texture of the C4AB crystal was analyzed by SEM. The presence of different vibrational groups in the grown crystal was identified using FTIR studies. The UV-visible spectra study indicated that C4AB crystal exhibits a broad transmittance range (75%) with a cut-off wavelength observed at 371 nm. The thermal study exposes that the grown crystal is thermally stable up to 178 °C. The etch pit density (EPD) of the C4AB crystal was observed by chemical etching studies. The dielectric response of the C4AB crystal has been studied at room temperature. The nonlinear optical properties such as n 2 , β and Third-order nonlinear optical (TONLO) susceptibility (χ (3) ) were assessed by Z-scan studies and the calculated values were found to be 2.34 × 10 −5  m/W, 3.63 × 10 −12 m 2 /W and χ (3)  = 3.345 × 10 −8 esu, respectively. The DFT calculations were employed to investigate the intrinsic properties of the C4AB molecule in quantum-chemical studies. The orbital energy, second-order hyperpolarizability and band gap were estimated by varying the applied field. Furthermore, DFT calculations were employed to determine the HOMO–LUMO energy gap, first-order hyperpolarizability and MESP analysis to explore the structure-property relationship.