Guangyao Zhao

Fullerene/Sulfur-Bridged Annulene Cocrystals: Two-Dimensional Segregated Heterojunctions with Ambipolar Transport Properties and Photoresponsivity

Fullerene/sulfur-bridged annulene cocrystals with a two-dimensional segregated alternating layer structure were prepared by a simple solution process. Single-crystal analysis revealed the existence of continuing π-π interactions in both the donor and acceptor layers, which serve as transport paths for holes and electrons separately. The ambipolar transport behaviors were demonstrated with single-crystal field-effect transistors and rationalized by quantum calculations. Meanwhile, preliminary photoresponsivity was observed with the transistor configuration.

High‐Performance Organic Field‐Effect Transistors Based on Single and Large‐Area Aligned Crystalline Microribbons of 6,13‐Dichloropentacene

Single and large-area aligned crystalline microribbons of 6,13-dichloropentacene (DCP) are prepared. The ribbons display excellent charge transport properties with a mobility of up to 9.0 cm(2) V(-1) s(-1) in ambient conditions, one of the highest values reported for organic semiconductors. The slipped π-π stacking with large intermolecular overlap is responsible for the high mobility of DCP ribbons.

Porphyrin Nanoassemblies via Surfactant-Assisted Assembly and Single Nanofiber Nanoelectronic Sensors for High-Performance H2O2 Vapor Sensing

Porphyrins are recognized as important π-conjugated molecules correlating supramolecular chemistry, nanoscience, and advanced materials science. So far, as their supramolecular nanoassemblies are addressed, most efforts focus on the photo- or opto-related subjects. Beyond these traditional subjects, it is strongly desired to develop advanced porphyrin nanoassemblies in some other new topics of paramount importance. By means of a surfactant-assisted assembly, we herein show that porphyrins of different central metal ions, 5,10,15,20-tetra(4-pyridyl)-21H,23H-porphine (H2TPyP), zinc 5,10,15,20-tetra(4-pyridyl)-21H,23H-porphine (ZnTPyP), and oxo-[5,10,15,20-tetra(4-pyridyl)porphyrinato]titanium(IV) (TiOTPyP), could be organized to form irregular aggregates, short nanorods, and long yet straight nanofibers, respectively. Remarkably, in terms of an organic ribbon mask technique, we show that such long yet straight TiOTPyP nanofibers could be integrated into single nanofiber-based two-end nanoelectronics. Such simple nanodevices could serve as high-performance sensors of a satisfactory stability, reproducibility, and selectivity for an expeditious detection of vapor-phase H2O2. This provides a new alternative for a fast sensing of vapor-phase H2O2, which is currently an important issue in the fields of anti-terrorism, industrial healthcare, etc. In contrast to the traditional investigations focusing on the photo- or opto-related topics, our work endows porphyrin nanostructures with new opportunities as advanced nanomaterials in terms of portable yet high-performance nanoelectronic sensors, which is an issue of general concern in modern advanced nanomaterials.

Charge-Transfer Complex Crystal Based on Extended-π-Conjugated Acceptor and Sulfur-Bridged Annulene: Charge-Transfer Interaction and Remarkable High Ambipolar Transport Characteristics

A single crystal of a novel mixed-stack donor-acceptor complex formed by a tetracyanoquinodimethane derivative with an extended π-conjugated system and a sulfur-bridged annulene displays the highest ambipolar transport behavior among donor-acceptor complexes reported with electron and hole mobilities reaching up to 0.24 and 0.77 cm(2) V(-1) s(-1) , respectively.

Tuning the Crystal Polymorphs of Alkyl Thienoacene via Solution Self‐Assembly Toward Air‐Stable and High‐Performance Organic Field‐Effect Transistors

The first example for thienoacene derivatives with selective growth of different crystal polymorphs is simply achieved by solution-phase self-assembly. Compared with platelet-shaped α-phase crystals, organic field-effect transistors (OFETs) based on microribbon-shaped β-phase crystals show a hole mobility up to 18.9 cm(2) V(-1) s(-1), which is one of the highest values for p-type organic semiconductors measured under ambient conditions.

High performance n-type single crystalline transistors of naphthalene bis(dicarboximide) and their anisotropic transport in crystals

High-performance n-type organic single crystal transistors of a naphthalene diimide are demonstrated. The accomplished transistors exhibit electron mobility as high as 0.7 cm(2) V(-1) s(-1). The anisotropic charge transport in the elongated hexagonal crystals of the naphthalene diimide is also explored. The transport anisotropy along different directions is at least 1.6 (mobility ratio).

Solution-sheared ultrathin films for highly-sensitive ammonia detection using organic thin-film transistors

The solution-shearing technique is utilized to fabricate large-area, ultrathin and continuous films of 1,4-bis((5′-hexyl-2,2′-bithiophen-5-yl)ethynyl)benzene (HTEB) for high-performance organic thin-film transistors (OTFTs), based on which highly sensitive, highly selective and reversible gas sensors exhibit outstanding response to NH3, with detection limit as low as 100 ppb.

Substitution effect on molecular packing and transistor performance of indolo[3,2-b]carbazole derivatives

In this manuscript, two chloro-substituted derivatives of indolo[3,2-b]carbazole (ICZ), 2,8-dichloro-indolo[3,2-b]carbazole (CICZ) and 2,8-dichloro-5,11-dihexyl-indolo[3,2-b]carbazole (CHICZ) were designed and synthesized. The only difference between CICZ and CHICZ is at the N-5 and N-11 positions with or without long alkyl side chains. Interestingly, CICZ and CHICZ exhibited similar thermal, optical, and electrochemical properties, while their molecular packing motifs in solid state and corresponding charge transport properties were significantly different. The alkyl chains at N-5 and N-11 positions were proved not only enhancing the solubility and self-organization of the compounds but also shifting the molecular packing from herringbone (CICZ) to one-dimensional π–π stacking (CHICZ). Moreover, nearly no field-effect performance was observed for CICZ, while the mobility of CHICZ was as high as 0.14 cm2 V−1 s−1 for its thin films and 0.5 cm2 V−1 s−1 for its single crystals. These results confirmed that the chemical substitutions are a powerful molecular design tool to tune the molecular packing motifs of organic semiconductors and their corresponding electronic properties.

A New Class of Extended Tetrathiafulvalene Cruciform Molecules for Molecular Electronics with Dithiafulvene‐4,5‐Dithiolate Anchoring Groups

Cruciform motifs with two orthogonally oriented π-extended tetrathiafulvalenes and with differently protected thiolate end-groups are synthesized by stepwise coupling reactions. The molecules are subjected to single-molecule conductivity studies in a break-junction and to conducting probe atomic force microscopy studies in a self-assembled monolayer on gold.

Large-Size 2D β-Cu2S Nanosheets with Giant Phase Transition Temperature Lowering (120 K) Synthesized by a Novel Method of Super-Cooling Chemical-Vapor-Deposition

2D triangular β-Cu2 S nanosheets with large size and high quality are synthesized by a novel method of super-cooling chemical-vapor-deposition. The phase transition of this 2D material from β-Cu2 S to γ-Cu2 S occurs at 258 K (-15 °C), and such transition temperature is 120 K lower than that of its bulk counterpart (about 378 K).