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During the long history of organic solar cells (OSCs), many excellent building blocks have emerged for the construction of high-performance electron donor/acceptor materials. Among them, the 4H-cyclopenta[2,1-b:3,4-b′]dithiophene (CPDT) unit was popular in the fullerene era, but declined in the early stage of the nonfullerene era. Recently, CPDT has experienced a revival with the emergence of low-cost nonfused-ring electron acceptors (NFREAs). This review aims to provide an overview of the structural isomers, photoelectric properties, and synthesis progress of the CPDT unit. Subsequently, the development of CPDT-based materials in the past few decades is summarized and discussed, including polymer donors for fullerene-based OSCs, NFREAs and polymerized NFREAs for nonfullerene-based OSCs. [ABSTRACT FROM AUTHOR]

With the consumption of shallow resources on the earth, the exploration and development of resources are constantly marching to the depth, and the conditions of strata encountered are becoming more and more complicated. Hard and dense formations, strong abrasive formations, and other complicated strata conditions have been a major hindrance to deep drilling. The diamond bits are widely used in geological resource development. Therefore, the comprehensive performance requirements of diamond bits are also increased. However, the existing diamond bits can only be applied to a certain formation and need to be replaced frequently, therefore, the research and development of broad-spectrum diamond bits with excellent formation applicability, high drilling efficiency, and long bit life is an important part of overcoming the deep drilling tasks. In recent years, the diamond drill bit has been developed rapidly, the structure, category, and performance have been greatly improved, and there also exists a certain improvement space. Therefore, this paper introduces the research status and important achievements of broad-spectrum diamond drills in recent years, including the improvement and application of drill structure and matrix performance, and then puts forward the research problems and future development direction of diamond drills with respect to the existing research results of broad-spectrum diamond drills. By summarizing the development trend of broad-spectrum diamond bits in this paper, the new research direction of diamond bit making technology and application field was revealed, which is of reference significance to the research and development of broad-spectrum diamond bits in the field of oil and gas exploration and mineral resources development. [ABSTRACT FROM AUTHOR]

In the development of high‐performance organic solar cells (OSCs), the self‐organization of organic semiconductors plays a crucial role. This study focuses on the precisely manipulation of molecular assemble via tuning alkyl side‐chain topology in a series of low‐cost nonfused‐ring electron acceptors (NFREAs). Among the three NFREAs investigated, DPA‐4, which possesses an asymmetric alkyl side‐chain length, exhibits a tight packing in the crystal and high crystallinity in the film, contributing to improved electron mobility and favorable film morphology for DPA‐4. As a result, the OSC device based on DPA‐4 achieves an excellent power conversion efficiency of 16.67 %, ranking among the highest efficiencies for NFREA‐based OSCs. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: By employing the asymmetric end‐group engineering, an asymmetric nonfused‐ring electron acceptor (NFREA) was designed and synthesized. Compared with the symmetric analogs (NoCA‐17 and NoCA‐18), NoCA‐19 possesses broader light absorption range, more coplanar π‐conjugated backbone, and appropriate crystallinity according to the experimental and theoretical results. The organic solar cells based on J52:NoCA‐19 exhibited a power conversion efficiency as high as 12.26%, which is much higher than those of J52:NoCA‐17 (9.50%) and J52:NoCA‐18 (11.77%), mainly due to more efficient exciton dissociation, better and balanced charge mobility, suppressed recombination loss, shorter charge extraction time, longer charge carrier lifetimes, and more favorable blend film morphology. These findings demonstrate the great potential of asymmetric end‐group engineering in exploring low‐cost and high‐performance NFREAs. [ABSTRACT FROM AUTHOR]

The structure of molecular aggregates is crucial for charge transport and photovoltaic performance in organic solar cells (OSCs). Herein, the intermolecular interactions and aggregated structures of nonfused-ring electron acceptors (NFREAs) are precisely regulated through a halogen transposition strategy, resulting in a noteworthy transformation from a 2D-layered structure to a 3D-interconnected packing network. Based on the 3D electron transport pathway, the binary and ternary devices deliver outstanding power conversion efficiencies (PCEs) of 17.46 % and 18.24 %, respectively, marking the highest value for NFREA-based OSCs., (© 2024 Wiley-VCH GmbH.)

In the development of high-performance organic solar cells (OSCs), the self-organization of organic semiconductors plays a crucial role. This study focuses on the precisely manipulation of molecular assemble via tuning alkyl side-chain topology in a series of low-cost nonfused-ring electron acceptors (NFREAs). Among the three NFREAs investigated, DPA-4, which possesses an asymmetric alkyl side-chain length, exhibits a tight packing in the crystal and high crystallinity in the film, contributing to improved electron mobility and favorable film morphology for DPA-4. As a result, the OSC device based on DPA-4 achieves an excellent power conversion efficiency of 16.67 %, ranking among the highest efficiencies for NFREA-based OSCs., (© 2024 Wiley-VCH GmbH.)