Two-dimensional conjugated polymers (2DCPs) have received great interest in smart devices due to their unique physical properties associated with flexibility, nanosized thickness, and correlated quantum size effect. Control of interlayer interactions of multilayer 2DCPs is crucial for modulating the confinement of charge carriers, heat, and photons to give remarkable properties because of the breaking of symmetry. However, to date, it is unclear how the multilayers of 2DCPs affect their physical properties. In this article, we for the first time perform a density functional theory calculation for the interlayer slipping effect on in-plane electronic properties of few-layer 2DCPs. Based on five homopolymers formed by C & horbar;C bonds with various stacking configurations beyond the inclined and serrated ones, results show that a moderate electric field causes the valence (conduction) band of few-layer 2DCPs to exhibit distinctive electrical characteristics which are dominated by the outermost two layers on hole (electron) enriched side. Analysis based on recombined molecular orbitals reveals that band properties are sensitive to the interlayer offsets when they result from the interference among multiple orbitals from each building block. This result provides a new guideline for manipulating charge transfer and spintronic properties of few-layer 2DCPs through an electric field to advance their various applications.

Developing high-mobility emissive organic semiconductors (OSCs) is crucial for organic light-emitting transistors (OLETs), which belong to a type of the smallest integrated optoelectronic devices, with great potential in next-generation display technologies. Although p-type high-mobility emissive OSCs have achieved considerable progress, n-type OSC materials have rarely been reported. Herein, we designed and synthesized an n-type dibenzothiophene sulfone-based emissive organic semiconductor of DPIDBSO with photoluminescence quantum yields (PLQYs) of 30% in the solid state. Interestingly, it was found that in the DPIDBSO crystal, the growth direction was along the short axis of the molecule rather than along the pi-pi stacking direction owing to multiple weak hydrogen bonds and the presence of a crystal growth dead zone. Leveraging this "special" crystal, DPIDBSO demonstrated typical n-type transport with an electron mobility of 0.17 cm2 V-1 s-1. More importantly, DPIDBSO-based devices with only Ag electrodes showed obvious electroluminescence with an immobile emission zone in the unipolar mode. This work provides deep insights into the development of n-type OSCs with tunable optoelectronic properties through the control of the aggregation state towards high-performance OLETs.

Organic light-emitting transistors (OLETs) have attracted increasing interest as promising multifunctional three-terminal optoelectronic devices for next-generation active-matrix flat-panel displays. The development of high color rendering index (CRI) white OLETs is essential for full-color display applications demanding excellent color fidelity. However, it remains challenging with the conventional approach of doping multiple guest emitters into a host matrix, requiring precise control needed over doping concentrations. Herein, a strategy is presented to fabricate high-CRI white OLETs using ultrathin emissive layers (UEMLs). This approach enables simple fabrication and efficient exciton management through 2D energy transfer across adjacent layers. The integrated OLET architecture uniquely combines electrical switching with high-quality white light emission. The resulting devices incorporating thickness-optimized yellow and red UEMLs exhibit uniform area emission with a low turn-on voltage below 6 V and a CRI exceeding 90. These are amongst the best performance values reported to date for ultrathin non-doped electroluminescent devices. Furthermore, a 12 × 20 OLET pixel array is fabricated and employed as a planar backlight, enabling a color gamut coverage of 117% of the national television standards committee (NTSC) standard and vivid full-color image display. This work provides a promising pathway for scalable, high-quality full-color OLET displays.

Smart agriculture is an inevitable trend in the modernization of agriculture. Achieving efficient and precise monitoring of trace pesticides is an important research direction in smart agriculture, with significant implications for a safe food supply chain. However, highly sensitive and high-throughput determination of pesticides still faces formidable challenges. Herein, we demonstrate a kind of sensitive and highly selective organophosphorus pesticide device based on organic field-effect transistors (OFETs). The unique signal amplification capability of OFETs and acetylcholinesterase modification on the active channel layer enables the achievement of accurate analysis of chlorpyrifos, parathion-methyl, and omethoate at the ppb level. Moreover, the simultaneous analysis of multiple samples is realized via the preparation of multichannel devices. Additionally, a portable monitoring applet is developed, enabling real-time assessment of the pesticide contamination status of samples based on the current response. This work provides a new avenue for constructing highly sensitive, real-time, high-flux intelligent agriculture sensing technology.

Narrow electroluminescence is in high demand for high-resolution displays, optical communication and medical phototherapy. Organic light-emitting transistors, as three-terminal electroluminescent devices, offer advantages in simplifying device architecture and achieving high efficiency under gate regulation. However, achieving high efficiency and narrow emission remains a challenge. Here we demonstrate that laterally integrated organic light-emitting transistors with intrinsic multiple-order microcavities can enhance efficiency and narrow emission with a universal capability for different emitters. Full-width at half-maximum values of 18 nm for red, 14 nm for green and 13 nm for blue were achieved with a maximum narrowed degree of 68%. This resulted in an impressive BT.2020 colour gamut of 97%. The peak current efficiency or blue index values for red, green and blue organic light-emitting transistors reached 26.3 cd A-1, 37.3 cd A-1 and 72.6, respectively. Moreover, organic light-emitting transistors exhibit much narrower emission and higher efficiency than equivalent, comparable devices due to their unique gate regulation capability. Our work could enable smart display technologies with high colour purity and enhanced efficiency.

Organic light-emitting transistors (OLETs) are highly integrated and minimized optoelectronic devices with significant potential superiority in smart displays and optical communications. To realize these various applications, it is urgently needed for color-tunable emission in OLETs, but remains a great challenge as a result of the difficulty for designing organic semiconductors simultaneously integrating high carrier mobility, strong solid-state emission, and the ability for potential tunable colors. Herein, a high mobility emissive excimer organic semiconductor, 2,7-di(2-anthryl)-9H-fluorene (2,7-DAF) was reasonably designed by introducing a rotatable carbon–carbon single bond connecting two anthracene groups at the 2,7-sites of fluorene, and the small torsion angles simultaneously guarantee effective conjugation and suppress fluorescence quenching. Indeed, the unique stable dimer arrangement and herringbone packing mode of 2,7-DAF single crystal enables its superior integrated optoelectronic properties with high carrier mobility of 2.16 cm 2  ⋅ V −1  ⋅ s −1 , and strong excimer emission with absolute photoluminescence quantum yield (PLQY) of 47.4 %. Furthermore, the voltage-dependent electrically induced color-tunable emission from orange to blue was also demonstrated for an individual 2,7-DAF single crystal based OLETs for the first time. This work opens the door for a new class of high mobility emissive excimer organic semiconductors, and provides a good platform for the study of color-tunable OLETs.

Organic semiconductors that possess both long exciton diffusion length and high mobility emissive properties are crucial for the development of high-performance organic optoelectronic devices. However, materials with these combined characteristics are currently rare. Herein, a long exciton diffusion length was obtained in the high mobility emissive organic semiconductor trans-1,2-bis(5-phenyldithieno[2,3-b:3 ',2 '-d]thiophen-2-yl)ethene (BPTTE). Excellent optoelectronic properties with the maximum carrier mobility of 18.1 cm(2) V-1 s(-1) and high photoluminescence quantum yield (PLQY) of 21.4% were obtained for BPTTE single crystals. Notably, an impressive exciton diffusion length reaching up to 114.2 nm was also achieved, demonstrating the effective integration of optoelectrical properties in BPTTE single crystals. This work offers valuable guidance for exploring the multifunctional capabilities of high mobility organic semiconductors, a crucial aspect for enhancing the performance of organic optoelectronic devices.

High-mobility emissive organic semiconductors integrate efficient charge transport and strong emission features. The development of these materials, which have the potential to overcome performance bottlenecks in organic electroluminescent and photoelectric conversion devices, is opening up new research directions in organic optoelectronics.

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 cm 2 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 × 10 5 and 6.43 × 10 4 A W −1 , and detectivity exceeding 5.68 × 10 17 and 2.99 × 10 16 Jones.

Anisotropical engineering of surface-confined supramolecules provides a potential approach to precisely tweaking the properties and performance of low-dimensional molecular nanomaterials. Here, we report the construction of a surface-confined bicomponent supramolecular structure that features structural anisotropy by combined scanning tunneling microscopy and density functional theory studies. One-dimensional supramolecular ribbons formed by corannulene with either titanyl phthalocyanine or copper phthalocyanine exclusively extend along the equivalent <1<(1)over bar>0> directions on Ag(111). Such a supramolecular anisotropy is demonstrated as a result of the combined effects of molecule-substrate commensurability and intermolecular interaction relaxation, which leads to orientation-dependent energy cost for commensurate growth of the supramolecular ribbon on Ag(111). These findings provide insights into the mediation effect of the fine balance between the molecule-substrate and intermolecular interactions on the supramolecular structures, offering an efficient methodology for supramolecular anisotropical engineering.

Integrating high charge-carrier mobility and low-threshold lasing action in an organic semiconductor is crucial for the realization of an electrically pumped laser, but remains a great challenge. Herein, we present an organic semiconductor, named as 2,7-di(2-naphthyl)-9 H -fluorene (LD-2), which shows an unexpected high charge-carrier mobility of 2.7 cm 2  V −1  s −1 and low-threshold lasing characteristic of 9.43 μJ cm −2 and 9.93 μJ cm −2 and high-quality factor (Q) of 2131 and 1684 at emission peaks of 420 and 443 nm, respectively. Detailed theoretical calculations and photophysical data analysis demonstrate that a large intermolecular transfer integral of 10.36–45.16 meV together with a fast radiative transition rate of 8.0×10 8  s −1 are responsible for the achievement of the superior integrated optoelectronic properties in the LD-2 crystal. These optoelectronic performances of LD-2 are among the highest reported low-threshold lasing organic semiconductors with efficient charge transport, suggesting its promise for research of electrically pumped organic lasers (EPOLs).

The development of high mobility organic laser semiconductors with strong emission is of great scientific and technical importance, but challenging. Herein, we present a high mobility organic laser semiconductor, 2,7-diphenyl-9 H -fluorene (LD-1) showing unique crystallization-enhanced emission guided by elaborately modulating its crystal growth process. The obtained one-dimensional nanowires of LD-1 show outstanding integrated properties including: high absolute photoluminescence quantum yield (PLQY) approaching 80 %, high charge carrier mobility of 0.08 cm 2  V −1  s −1 , Fabry-Perot lasing characters with a low threshold of 86 μJ cm −2 and a high-quality factor of ≈2400. Furthermore, electrically induced emission was obtained from an individual LD-1 crystal nanowire-based light-emitting transistor due to the recombination of holes and electrons simultaneously injected into the nanowire, which provides a good platform for the study of electrically pumped organic lasers and other related ultrasmall integrated electrical-driven photonic devices.

The conformational isomers of Salen molecules and their self-assembled structures on coinage metal surfaces.

Organic single crystals with excellent optical and electrical properties are critical for the development of organic optoelectronics. Herein, two compounds 9,10‐bis([ N , N ‐diphenyl]‐4′‐phenylethynyl)anthracene (TPA‐An) and 9,10‐bis([1′,3′‐diphenyl]‐5′‐phenylethynyl)anthracene (TBA‐An) are synthesized by introducing two different luminescent groups, triphenylamine and 1,3‐diphenylbenzene, at the 9,10 positions of anthracene via triple bond connection. Single crystals based on TPA‐An and TBA‐An with a ribbon morphology obtained through the slow solvent‐evaporation method exhibit high photoluminescence quantum yields (PLQYs) of 98% and 99% at room temperature, and remarkable hole mobilities of 0.45 and 0.15 cm 2 V −1 s −1 in single‐crystal organic field‐effect transistors (SC‐OFETs). Furthermore, UV phototransistors based on the two single crystals obtain photosensitivities of 1.03 × 10 3 and 3.45 × 10 4 , ultrahigh photoresponsivities of 7.19 × 10 5 and 1.50 × 10 5 A W −1 , and the detectivities exceeding 1.40 × 10 16 and 1.60 × 10 17 Jones.

2,9-DPh-DNTT, an isomeric of diphenyl-dinaphtho[2,3-b:2',3'-f]-thieno[3,2-b] thiophene (DPh-DNTTs), is an emerging candidate of high mobility organic semiconductor material. In this work, a high performance 2,9-D-PhDNTT organic thin-film transistor (OTFT) is fabricated by the method of weak epitaxy growth. The quality of 2,9DPh-DNTT thin film was significantly improved when its epitaxial layer grows on an inducing layer of parasexiphenyl (p-6P). Continuous large-area, highly ordered and terraced 2,9-DPh-DNTT polycrystalline thin films are obtained. The hole mobility of as-fabricated 2,9-DPh-DNTT thin-film transistor reaches up to 6.4 cm(2) V(-1)s(-1). This simple process of preparing high mobility 2,9-DPh-DNTT thin-film transistor supplies a facile route of largearea OTFT fabrication.

Electrically conductive coordination polymers (generally known as metal-organic frameworks, MOFs) are a class of crystalline hybrid materials produced by the reasonable self-assembly of metal nodes and organic linkers. The unique and intriguing combination of inorganic and organic components endows coordination polymers with superior optical and electrical properties, which have recently aroused much attention in several electronic and optoelectronic technological applications. However, there are many challenging obstacles and issues that need to be addressed in this burgeoning field. In this Perspective, we first provide a fundamental understanding about the electronic design strategies that provide better guidance for realizing high conductivities and good mobilities in coordination polymers. We then examine the current established synthetic approaches to construct high-quality working samples of electrically conductive coordination polymers for device integration. This is followed by a discussion of the current state-of-the-art progress toward the preliminary achievements in (opto)electronic devices spanning chemiresistive sensors, field-effect transistors, organic photovoltaics, photodetectors, etc. Finally, we conclude this Perspective with the existing hurdles and limitations in this area, along with the critical directions and opportunities for future research.

Potassium (K) cations are spontaneously formed upon thermal deposition of low-coverage K onto an ultrathin CuO monolayer grown on Cu(110) and they were explored by low-temperature scanning tunneling microscopy (STM) and X-ray photoemission spectroscopy. The formed K cations are highly immobile and thermally stable. The local work function around an individual K cation decreases by 1.5±0.3 eV, and a charging zone underneath it is established within about 1.0 nm. The cationic and neutral states of the K atom are switchable upon application of an STM bias voltage pulse, which is simultaneously accompanied by an adsorption site relocation.

: Pure organic radical molecules on metal surfaces are of great significance in exploration of the electron spin behavior. However, only a few of them are investigated in surface studies due to their poor thermal stability. The adsorption and conformational switching of two verdazyl radical molecules, namely, 1,5-biisopropyl-3-(benzo[b]benzo[4,5]thieno[2,3-d]thiophen-2-yl)-6-oxoverdazyl (B2P) and 1,5-biisopropyl-3-(benzo[b]benzo[4,5]thieno[2,3-d]thiophen-4-yl)-6-oxoverdazyl (B4P), are studied by scanning tunneling microscopy (STM) and density functional theory (DFT). The adsorbed B2P molecules on Au(111) form dimers, trimers and tetramers without any ordered assembly structure in which two distinct appearances of B2P in STM images are observed and assigned to be its “P” and “T” conformations. The “P” conformation molecules appear in the STM image with a large elliptical protrusion and two small ones of equal size, while the “T” ones appear with a large protrusion and two small ones of different size. Likewise, the B4P molecules on Au(111) form dimers at low coverage, strip structure at medium coverage and assembled structure at high coverage which also consists of above-mentioned two conformations. Both B2P molecules and B4P molecules are held together by weak intermolecular interaction rather than chemical bond. STM tip induced conformational switching of both verdayzl radicals is observed at the bias voltage of +2.0 V. The “T” conformation of B2P can be switched to the “P” while the “P” conformation of B4P can be switched to the “T” one. For both molecules, such a conformational switching is irreversible. The DFT calculations with Perdew-Burke-Ernzerhof version exchange-correlation functional are used to optimize the model structure and simulate the STM images. STM images of several possible molecular conformations with different isopropyl orientation and different tilt angle between verdazyl radical and Au(111) surface are simulated. For conformations with different isopropyl orientation, the STM simulated images are similar, while different tilt angles of verdazyl radical lead to significantly different STM simulated images. Combined STM experiments and DFT simulations reveal that the conformational switching originates from the change of tilting angle between the verdazyl radical and Au(111) surface. The tilt angles in “P” and “T” conformations are 0° and 50°, respectively. In this study, two different adsorption conformations of verdazyl radicals on the Au(111) surface are presented and their exact adsorption structures are identified. This study provides a possible way to study the relationship between the electron spin and configuration conversion of pure organic radical molecules and a reference for designing more conformational switchable radical molecules that can be employed as interesting molecular switches.