Polaritons can be considered as a ‘hybrid’ particle made up of light and matter. Polaritons may bahave “anisotropically” in certain medium where the structural and electronic properties are different in different directions. Such phenomenon is very intriguing as it enables enhanced density of optical states and ray-like directional propagation of polaritons. The authors of this manuscript (DOI: 10.1002/inf2.12119) give an overview of the recent progress in in-plane anisotropic polaritons launched and visualized in the near-field range in 2D layered van der Waals materials. Future prospects in this emerging but promising field are featured on the basis of its potential applications in flat optics, thermal heat management, bio-sensing or quantum optics.

Conductive hydrogels are promising candidates for the fabrication of flexible electronics by integrating electron-conductive or ion-conductive components in hydrogels, transferring the stimuli-responsiveness into electrical signals and collecting physiological signals for monitoring human health. (DOI: 10.1002/inf2.12113)

Two-dimensional (2D) CdSe Nanoplatelets (NPLs) have proven to be an excellent optoelectronic material with many unique optical properties. In this cover, the flat design represents the world of two-dimensional materials. CdSe NPLs have high-purity color emission and a wide adjustable emission range. This is like the colorful auspicious clouds generated by the interaction of sun and clouds. The flying Birds in the sky represent various applications derived from CdSe NPLs. The birds filled with different patterns represent display applications, optical gain applications, and optoelectronic applications. The 2D CdSe NPLs material brings a colorful two-dimensional world, representing its great development potential in the future. (DOI: 10.1002/inf2.12106)

The low-loss and highly anisotropic polaritons in natural in-plane hyperbolic materials could open a new paradigm in nanophotonics, promising an unprecedented potential for the directional control of light and light-matter interactions at the nanoscale.

We summarize the recent advances in stimulus-responsive room temperature phosphorescence in purely organic luminogens, focusing mainly on their unique emission behaviors and internal mechanisms, aiming to construct the relationship between the mechanism, luminogens, and possible applications.

This review article surveys the strategies of addressing the cycling instability challenges associated with pseudocapacitive materials, including conjugated polymers, metal oxides, metal nitrides, metal carbides, and metal sulfides. Additionally, the article summarizes the failure modes of these materials, explains the mechanisms of the resolutions, and discusses the opportunities for obtaining pseudocapacitive electrodes with long-lasting charge-storage performance.

Flexible electronics can not only collect physiological signals for human health monitoring but also enrich our daily life with multifunctional smart devices by serving as ideal interfaces bridging biological systems and conventional electronic devices. In this review, recent advances in the design of conductive hydrogels (CHs) for flexible electronics are highlighted. Extensive electron-CHs and ionic-CHs as well as their hybrids are reviewed based on both fabrication strategies and associated applications in flexible electronics such as biosensors, batteries, supercapacitors, nanogenerators, actuators, touch panels, and displays. Current challenges and future research perspectives of CHs are also proposed.

The development of flexible lithium-ion batteries for flexible electronic devices is reviewed from the aspects of battery structural design, active materials incorporation, and techniques to evaluate mechanical and electrochemical performance. Future research direction, particularly the need for standardized operando methods to probe the degradation of FLIBs is discussed.

Computational functionality-driving design currently becomes a powerful approach for accelerating discovery of advanced materials, thus often enlisting the tools of theoretical computations to spearhead the developing novel functional material. A range of simulation techniques are being widely developed and applied to predict key properties related to materials for various optoelectronic applications. Such techniques vary from crystal-structure prediction (global optimization algorithm), inverse design of the material from the functionality oriented physical principles and high-throughput in-silico computational screening. We here review these design strategies and the computational methods associated with solid-state physicals that have applied to the development of novel optoelectronic materials by a few representative examples.

CdSe nanoplatelets (NPLs) is a quasi-two-dimensional nanomaterial with many unique properties, such as narrow emission peak, large absorption cross-section, large exciton binding energy and high optical gain. This review summarizes the optical properties and various applications of CdSe NPLs in recent years and point out some challenges, which will promote the further development of NPLs.

A synergistic engineering between graphene oxide (GO), polyaniline (PANI), and Poly(ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) was accomplished to introduce additional energy levels between perovskite and PEDOT:PSS and increase the conductivity of PEDOT:PSS. A higher performance for p-i-n perovskite solar cells has been obtained by adding the mixed dopant of GO, PANI, and PEDOT:PSS, demonstrating better stability than the pristine PEDOT:PSS cell.

A three-electrode Li-ion coin cell with a Li reference electrode enables to simultaneously record the cell's voltage and electrodes’ potentials, and individually measure the cell's and electrodes’ impedances. A health graphite-LiNi_0.80Co_0.15Al_0.05O₂ Li-ion cell shows much higher impedance of the cathode than the anode, which makes it possible to safely charge Li-ion cells up to 10C without Li plating on the graphite anode.

Presented are the novel nine atomic layered V₄C₃T _x MXene and its ternary metal oxide hydroxides modified derivatives (denoted as MOOH@V₄C₃T _x, M = Ni, Fe, and V). The nanohybrids present good OER activity and excellent long-time stability, which demonstrates the promising future of multilayered M₄X₃ MXenes as substrates for the reactive synthesis of advanced energy conversion and storage materials.

Intrinsic quantum conductance behaviour is evoked by Bi CF in BiVO4 matrix

Spin current with out-of-plane polarization is generated in monolayer WSe₂ by passing charge current in the transverse direction. Spins diffuse through a graphene channel and get detected by a non-local spin valve that consists of a ferromagnetic electrode and a non-magnetic electrode. This is the first time that valley locked out-of-plane spins are electrically generated and detected, which sheds light on potential valleytronic applications and novel information transport and storage.

The issue of ineffective carrier transport and collection of multilayered materials in the randomly oriented polycrystalline thin-film is tackled by producing the 3D heterojunction BiI3 NSs solar cells, which embed vertically aligned monocrystalline BiI3 NSs into spiro-OMeTAD. The preferred orientation of BiI3 NSs and large p-n junction areas enable a strong light absorption and effective carrier transport and collection.

A fluorinated phosphate electrolyte (0.8 M LiPF₆/tris(2,2,2-trifluoroethyl) phosphate + 5 vol% fluoroethylene carbonate + 5 vol% vinylene carbonate) with completely nonflammability and excellent oxidative/reductive stability is proposed for high-safety 4.5 V-class Li-ion batteries (Si-SiC-C/0.35Li₂MnO₃·0.65LiNi_0.5Mn_0.5O₂). The FEC-VC coadditives not only contribute to a stable solid electrolyte interface film on anode but a stable cathode electrolyte interface on cathode.