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It remains challenging to comprehensively understand the packing models of conjugated polymers, in which side chains play extremely critical roles. The side chains are typically flexible and non‐conductive and are widely used to improve the polymer solubility in organic solutions. Herein, a buffer chain model is proposed to describe link between conjugated backbone and side chains for understanding the relationship of crystallization competition of conductive conjugated backbones and non‐conductive side chains. A longer buffer chain is beneficial for alleviating such crystallization competition and further promoting the spontaneous packing of conjugated backbones, resulting in enhanced charge transport properties. Our results provide a novel concept for designing conjugated polymers towards ordered organization and enhanced electronic properties and highlight the importance of balancing the competitive interactions between different parts of conjugated polymers. [ABSTRACT FROM AUTHOR]

As simple and versatile tools, additives have been widely used to refine active layer morphology and have played a crucial role in boosting the power conversion efficiency (PCE) of organic solar cells (OSCs). Herein, three novel solvent additives named Th‐FSi, Th‐ClSi, and Th‐BrSi with the same backbone of 2,5‐bis(trimethylsilyl)thiophene are designed and synthesized by substituting different halogens of fluorine, chlorine, and bromine, respectively. Notably, Th‐ClSi exhibits the more significant dipole moment and engages in non‐covalent interactions with a small‐molecule acceptor (SMA) L8‐BO, which slight adjustments in intermolecular interaction, crystallinity, and molecular packing in the PM6:L8‐BO active layer. Consequently, the OSCs incorporating Th‐ClSi outperform their Th‐FSi and Th‐BrSi counterparts in photo‐capturing, reduced energy loss, superior exciton dissociation, and charge transfer properties, out‐coming yields in an enhanced PCE of 18.29%. Moreover, by integrating a near‐infrared absorbing SMA (BTP‐eC9) guest into the PM6:L8‐BO matrix, the absorption spectrum to span 880–930 nm, and the resultant ternary OSCs achieve a commendable PCE of 19.17%, ranking among the highest efficiencies reported to date is expanded. These findings underscore the promise of halogenated thiophene‐based solvent additives as a potent avenue for morphological fine‐tuning and consequent PCE enhancement in OSCs. [ABSTRACT FROM AUTHOR]

Abstract When underground tunnels in coal mines traverse geological structurally abnormal zones (faults, collapse columns, fractured zones, etc.), excavation-induced unloading leads to instability and failure of the engineering rock mass. Rock masses in fractured zones are in elastic, plastic, and post-peak stress states, and the process of excavation through these zones essentially involves unloading under full stress paths. To explore the mechanical response of sandstone under different stress levels, based on the investigation of possible stress paths, a systematic study is conducted on various unloading paths, including elastic-axial compression with unloading of confining pressure, elastic-constant principal stress with unloading of confining pressure, plastic-axial compression with unloading of confining pressure, plastic-constant principal stress with unloading of confining pressure, plastic-constant axial D 1 displacement with unloading of confining pressure, plastic-equal proportional unloading of axial and confining pressures, and post-peak-synchronous unloading of axial and confining pressures. Characteristics of full stress-strain curves under seven unloading paths are obtained. The deformation patterns caused by unloading are analyzed, and the relationship between unloading paths and strain increments is investigated. Results show that, as the degree of unloading increases, the unloading deformation modulus ( E ) in the elastic stress state exhibits a trend of initial increase, then stabilization, followed by decrease, while in the plastic stress state, E gradually decreases. Both elastic and plastic states show an increasing trend in Poisson’s ratio (µ). The normalized plastic shear strain γ p /γ p max and dilation angle (ψ) conform to a single exponential function, and there is a negative correlation between initial confining pressure and dilation angle. These findings support the enrichment and development of unloading rock mechanics.

Incorporating heteroatoms can effectively modulate the molecular optoelectronic properties. However, the fundamental understanding of BN doping effects in BN‐embedded polycyclic aromatic hydrocarbons (PAHs) is underexplored, lacking rational guidelines to modulate the electronic structures through BN units for advanced materials. Herein, a concise synthesis of novel B2N2‐perylenes with BN doped at the bay area is achieved to systematically explore the doping effect of BN position on the photophysical properties of PAHs. The shift of BN position in B2N2‐perylenes alters the π electron conjugation, aromaticity and molecular rigidness significantly, achieving substantially higher electron transition abilities than those with BN doped in the nodal plane. It is further clarified that BN position dominates the photophysical properties over BN orientation. The revealed guideline here may apply generally to novel BN‐PAHs, and aid the advancement of BN‐PAHs with highly‐emissive performance. [ABSTRACT FROM AUTHOR]