Silicon and oxygen synergistic effects for the discovery of new high-performance nonfullerene acceptors

Abstract

In organic electronics, an aromatic fused ring is a basic unit that provides π-electrons to construct semiconductors and governs the device performance. The main challenge in developing new π-skeletons for tuning the material properties is the limitation of the available chemical approach. Herein, we successfully synthesize two pentacyclic siloxy-bridged π-conjugated isomers to investigate the synergistic effects of Si and O atoms on the geometric and electronic influence of π-units in organic electronics. Notably, the synthesis routes for both isomers possess several advantages over the previous approaches for delivering conventional aromatic fused-rings, such as environmentally benign tin-free synthesis and few synthetic steps. To explore their potential application as photovoltaic materials, two isomeric acceptor–donor–acceptor type acceptors based on these two isomers were developed, showing a decent device efficiency of 10%, which indicates the great potential of this SiO-bridged ladder-type unit for the development of new high-performance semiconductor materials.

Two-Dimensional Cu2MoS4-Loaded Silicon Nanospheres as an Anode for High-Performance Lithium-Ion Batteries

“…In the process of lithium intercalation, the material and lithium ions form the Si–Li alloy, resulting in the formation of the large spacing of the crystal lattice during delithium, which is adverse to maintaining the stability of the structure. The self-assembled Cu 2 MoS 4 /SiNS material has enough interlayer space to insert and store lithium ions when silicon atoms (atomic radius of 111 pm) exist between the layers (Figure e) . This reveals that the combination of silicon and two-dimensional materials through self-assembly can effectively improve the electrical conductivity of the material, thereby improving the stability.…”

A π-extended triphenylamine based dopant-free hole-transporting material for perovskite solar cells via heteroatom substitution

“…This can also be extended to the Group 14 analogues, whereby the HOMO levels of R-Si and R-Ge are much more stable than that of R-C , which is observed as a longer C – Si/C – Ge bond length and specific interactions (σ*–π* conjugation) between the Si/Ge atom and the π-electron system. 37 For the Group 16 analogues, R-Se displayed a slightly lower HOMO energy level compared to R-O and R-S due to vacant d-orbitals and the spin–orbit coupling of Se atoms. These results can be substantiated by analyzing the percentage contribution of the central core fragment to the molecular HOMO level, as shown in Fig.…”

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

“…Based on the above results, we propose that the different optoelectronic performances of the molecules can be attributed to the silicon–oxygen substitution on the molecular coplanarity and steric hindrance for packing. The introduction of silicon atoms enhances the effect of isomerization on the molecular structure because of the large silicon atomic radius and long C–Si bond . The short distance between two Si atoms results in large dihedral angles between two phenyl subunits and a relatively large steric hindrance (PLCF-Si-O).…”

“…Conjugated organic molecules endowed with delocalized π electrons have emerged as promising candidates for optoelectronic devices such as solar cells, − field-effect transistors, − and photodetectors. − Embedding heteroatoms into the π-fused frameworks is a feasible strategy for enhancing the structural diversity of conjugated semiconducting molecules, thus leading to tunable solubility, crystallinity, electronic structure, and photophysical properties. − Recently, π-fused frameworks with silicon or carbon atoms as bridging moieties have been discovered with intriguing optoelectronic performance. ,, In particular, the silylene bridges between the adjacent aryl rings not only improve the solution processability by introducing aliphatic side chains with the extra valence but also modulate the energy band structure of the parent π-conjugated system via the interaction between the π* and the σ* orbitals of the exocyclic silicon–carbon bonds. ,, More recent findings have revealed that the incorporation of electron-rich oxygen atoms into ladder-type scaffolds would greatly improve the light-harvesting capability and the electron-donating capability of the unit, thus enhancing the power conversion efficiency of organic photovoltaics. , However, the impacts of silicon–oxygen (Si–O) substitution on the molecular structure and their self-assembly behavior have not been well understood. Insights into the relationship between heteroatoms and the intermolecular packing structure are of great significance for regulating the assembly process and constructing integrated organic optoelectronic devices based on molecular engineering.…”