Controlled Assembly of Conjugated Ladder Molecules with Different Bridging Structures toward Optoelectronic Application

Abstract

Structural design of organic π-conjugated small molecules allows the energy band structure and electronic properties of the molecules to be tuned as needed, which provides a feasible strategy for enhancing the performance of optoelectronic devices. The introduction of bridging structures is a common structural modification method to adjust the rigidity and coplanarity of the molecular backbone, thus affecting the molecular packing. However, patterning of organic single-crystalline microstructures based on conjugated ladder molecules with different bridging structures still remains challenging for large-area integration of optoelectronic devices. In this paper, a controlled dewetting process is applied to obtain organic single-crystalline arrays with precise positioning and a regular morphology based on two isomers with silicon–oxygen bridging and their two carbon–oxygen-bridged analogues. Molecules with different bridging structures show disparate packing models due to the difference of dihedral angles and ring tensions. A microwire-array ultraviolet photodetector based on the oxygen–silicon-bridging ladder molecule exhibits a high light on/off ratio of 24 and a responsivity of 0.63 mA W–1 owing to the effective π–π stacking governed by the molecular planarity. This work not only provides a universal method for the integration of organic optoelectronic devices but also explains the effect of bridging structure engineering on molecular assembly and optoelectronic performance.

Recent Progress in Transition Metal‐Catalyzed Hydrosilane‐Mediated C−H Silylation

“…Later, Wang, Zhao and Wu group found C/Si switch on conjugated ladder molecules with different bridging structure made a great influence on optoelectronic devices (Scheme 13(c)) [21] . The experimental results demonstrated that introduction of silicon atom into conjugated ladder molecules the tension of the six‐membered ring could be released, which was beneficial to the molecular planarity and π‐π stacking, improving the transport of carriers.…”

Microstructures Formation through Liquid‐Assisted Assembly of Functional Materials for High‐Performance Electronics

“…[85,120,154] Single-crystal materials with excellent electrical properties and high photoelectric conversion efficiency play an important role in highspeed and optical fiber communications. [155][156][157] Furthermore, supramolecular materials and conjugated polymers are extensively used in photodetectors to enhance sensitivity and response speed. [112] With the increasing demand for portable and wearable devices and flexible electronics, flexible photodetectors have become a research hotspot.…”

High‐Performance Organic Phototransistors Based on Single‐Crystalline Microwire Arrays

“…[2,[24][25][26][27][28][29] On the other hand, organic molecules are arranged with 𝜋-stacking direction parallel to the long axis of microwires, which increases the overlap of the electronic wave functions between the packed molecules, thus forming an optimal carrier transport path in channels. [19,24,[29][30][31][32][33] Furthermore, microarray phototransistor possessing suppressed pixel crosstalk can be integrated monolithically with external components to realize high-throughput active-matrix sensor arrays. As a result, organic single-crystalline 1D microarrays are promising for constructing high-performance OPTs toward next-generation optoelectronics to meet the increasing demand for integrated optoelectronic circuits.…”