In order to utilize the near-infrared (NIR) solar photons like silicon-based solar cells, extensive research efforts have been devoted to the development of organic donor and acceptor materials with strong NIR absorption. However, single-junction organic solar cells (OSCs) with photoresponse extending into >1000 nm and power conversion efficiency (PCE) >11% have rarely been reported. Herein, three fused-ring electron acceptors with varying core size are reported. These three molecules exhibit strong absorption from 600 to 1000 nm and high electron mobility (>1 × 10 cm V s ). It is proposed that core engineering is a promising approach to elevate energy levels, enhance absorption and electron mobility, and finally achieve high device performance. This approach can maximize both short-circuit current density (  J ) and open-circuit voltage (V ) at the same time, differing from the commonly used end group engineering that is generally unable to realize simultaneous enhancement in both V and J . Finally, the single-junction OSCs based on these acceptors in combination with the widely polymer donor PTB7-Th yield J as high as 26.00 mA cm and PCE as high as 12.3%.

Solid-state lithium metal batteries with solid electrolytes are promising for next-generation energy-storage devices. However, it remains challenging to develop solid electrolytes that are both mechanically robust and strong against external mechanical load, due to the brittleness of ceramic electrolytes and the softness of polymer electrolytes. Herein, we propose a nacre-inspired design of ceramic/polymer solid composite electrolytes with the "brick-and-mortar" microstructure. The nacre-like ceramic/polymer electrolyte (NCPE) simultaneously possesses a much higher fracture strain (1.1%) than pure ceramic electrolytes (0.13%) and a much larger ultimate flexural strength (7.8 GPa) than pure polymer electrolytes (20 MPa). The electrochemical performance of NCPE is also much better than pure ceramic or polymer electrolytes, especially under mechanical load. A 5 × 5 cm 2 pouch cell with LAGP/poly(ether−acrylate) (PEA) NCPE exhibits stable cycling with a capacity retention of 95.6% over 100 cycles at room temperature, even undergoes a large This article is protected by copyright. All rights reserved. point load of 10 N. In contrast, cells based on pure ceramic and pure polymer electrolyte show poor cycle life. The NCPE provides a new design for solid composite electrolyte and opens up new possibilities for future solid-state lithium metal batteries and structural energy storage. The rapid-growing demands for portable electronics and electric vehicles have bolstered needs for next-generation lithium batteries with high energy density [1-4]. However, lithium batteries become more thermally vulnerable as energy density increases. Thermal runaway and explosion are prone to be triggered by failures such as mechanical damage and lithium dendrite growth inside batteries [5, 6]. Nonflammable solid-state ceramic electrolytes (SSEs) provide alternatives to conventional flammable liquid electrolytes [7-9]. Various ceramic electrolytes with attractive ionic conductivities have been developed in the past two decades, including NASICON-type Li 1.5 Al 0.5 Ge 1.5 (PO 4) 3 (LAGP) [10] , Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP) [11, 12] , garnet Li 7 La 3 Zr 2 O 12 (LLZO) [13, 14] , and sulfides, such as This article is protected by copyright. All rights reserved. NCPEs, polymer electrolytes and ceramic electrolytes were cut with a thickness of 500 μm and a size of 1.5 cm. A loading rate of 0.5 mm min-1 and a support span of 1.5 cm were used in all tests. The results were averaged from those in five similar specimens. The flexural stress is and The flexural strain is , where F, L, w, h, and D are the applied point force, span length, sample width, thickness, and flexural deflection, respectively. Vickers indentation was carried out on SANS-UTM 6000 using a Vickers indenter. Finite Element Mechanical Simulation: 2D nonlinear finite element simulations were conducted using the software ABAQUS v6.14. In these simulations, the stress/strain distributions and crack propagation in a regular brick-mortar structure and a ceramic film are calculate...

We report 4 fused-ring electron acceptors (FREAs) with the same end-groups and side-chains but different cores, whose sizes range from 5 to 11 fused rings. The core size has considerable effects on the electronic, optical, charge transport, morphological, and photovoltaic properties of the FREAs. Extending the core size leads to red-shift of absorption spectra, upshift of the energy levels, and enhancement of molecular packing and electron mobility. From 5 to 9 fused rings, the core size extension can simultaneously enhance open-circuit voltage (V OC ), short-circuit current density (J SC ), and fill factor (FF) of organic solar cells (OSCs). The best efficiency of the binary-blend devices increases from 5.6 to 11.7%, while the best efficiency of the ternary-blend devices increases from 6.3 to 12.6% as the acceptor core size extends.

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