Hierarchical Self-Assembly of Conjugated Block Copolymers and Semiconducting Nanorods into One-Dimensional Nanocomposites

Abstract

Semiconducting organic–inorganic nanocomposites comprising conjugated polymers (CPs) and semiconducting nanocrystals (NCs) represent an important class of functional materials. The ability to organize CPs and NCs into self-assembled nanostructures in close proximity may enable efficient charge or energy transfer between them for use in flexible electronics, light-emitting displays, and photovoltaics. Herein we report the crafting of one-dimensional (1D) functional nanocomposites composed of all-conjugated diblock copolymers and CdSe nanorods (NRs) via two consecutive self-assembly processes, namely, self-assembly of poly­(3-hexyl­selenophene)-block-poly­(3-butyl­selenophene) (denoted P3HS-b-P3BS) diblock copolymers into nanofibers, followed by self-assembly of P3HS-b-P3BS nanofibers and CdSe NRs to yield P3HS-b-P3BS–CdSe NR nanocomposites. Notably, P3HS-b-P3BS diblock copolymers are first rationally designed and synthesized, exhibiting a narrow optical bandgap and forming nanofibers due to strong interchain π–π stacking (i.e., first self-assembly). Subsequently, the addition of CdSe NRs into P3HS-b-P3BS nanofiber solution results in the formation of 1D P3HS-b-P3BS–CdSe NR nanocomposites driven by the van der Waals interaction between aliphatic ligands on the surface of CdSe NRs and the hexyl side chains of P3HS-b-P3BS and the coordination interaction between the selenium of P3HS and the surface of CdSe NRs (i.e., second self-assembly). Quite intriguingly, an integrated Monte Carlo simulation and experimental study reveals that CdSe NRs are aligned parallel to the long axis of P3HS-b-P3BS nanofibers in an end-to-end mode at low concentration of CdSe. When high concentration of CdSe NRs is introduced, coexistence of the side-by-side and layer-by-layer assemblies of CdSe NRs along P3HS-b-P3BS nanofibers is yielded. Photoluminescence quenching of CdSe NRs is observed, suggesting an efficient charge transfer between CdSe and P3HS-b-P3BS. Such self-assembled conjugated diblock copolymer–quantum rod nanocomposites may find applications in optics, optoelectronics, and sensors.

Unravelling the Correlation between Microphase Separation and Cocrystallization in Thiophene-Selenophene Block Copolymers for Organic Field-Effect Transistors

“…The d 010 of P3HT and P3BS are 3.8 and 4.2 Å, according to the scattering vectors ( q x , y ) of 16.7 and 14.9 nm –1 , respectively (Figures S7c and S8c; Table ). The diffraction peaks with the d 100 of 16.3 and 9.9 Å can be assumed as P3HT form I crystal and P3BS form II crystal, respectively. As the diffraction peak intensity is approximately proportional to the materials crystallinity, the stronger intensity of (100) diffraction of P3HT indicates it has a higher crystallinity than P3BS form II (Figures S7a and S8a).…”

“…P3HT- b -P3BS BCPs with various P3HT/P3BS block ratios were synthesized by Grignard metathesis (GRIM) polymerization based on our previous report. − As a representative, the procedure for the synthesis of P3HT- b -P3BS with a feed molar ratio of 60:60 was given as follows: 2-bromo-5-iodo-3-hexylthiophene (0.895 g, 2.4 mmol) was dissolved in THF (60 mL) in a three-neck flask and stirred under N 2 . After cooling the solution to 0 °C, i -PrMgCl in THF (1.2 mL, 2.4 mmol) was added via a syringe, and the mixture was stirred for 30 min.…”

Large‐Scale Rapid Positioning of Hierarchical Assemblies of Conjugated Polymers via Meniscus‐Assisted Self‐Assembly

“…due to the spatial arrangement of nanomaterials over multiple length scales [1] . In this context, several solution‐based techniques, such as template‐directed assembly, [2] bottom‐up assembly, [3, 4] and inkjet printing, [5] have been developed to yield hierarchically ordered assemblies. Notably, these approaches often involve the use of expensive equipment or require a complex multistep process for template preparation or assembly formation.…”

Self‐Assembled Nanostructures of Quantum Dot/Conjugated Polymer Hybrids for Photonic Synaptic Transistors with Ultralow Energy Consumption and Zero‐Gate Bias

“…Researchers have developed new functional nanomaterials to replace conventional scaling methods, which offer inexpensive solutions for microelectronic devices. Solution‐based self‐assembly involved formation methods at room temperature are one of the bottom–up synthetic strategies and have attracted the most attention thanks to their simplicity and ease of applicability in large‐scale production beyond the limit of conventional semiconductors, as they can produce nanostructures such as anisotropic 1D morphologies of organic polymers, [ 1,2 ] polymer‐small molecule hybrids, [ 3–5 ] copolymers, [ 6–8 ] and organic–inorganic hybrids, [ 9–11 ] with high crystallinity, monodispersity, and unique electronic and optical properties.…”