Materials Horizons最新文献

Correction for ‘Photocatalytic membranes based on Cu–NH₂-MIL-125(Ti) protected by poly(vinylidene fluoride) for high and stable hydrogen production' by Emilia Gontarek-Castro et al., Mater. Horiz., 2025, https://doi.org/10.1039/d4mh01397b.

Quantum dots have garnered significant interest in perovskite solar cells (PSCs) due to their stable chemical properties, high carrier mobility, and unique features such as multiple exciton generation and excellent optoelectronic characteristics resulting from quantum confinement effects. This review explores quantum dot properties and their applications in photoelectronic devices, including their synthesis and deposition processes. This sets the stage for discussing their diverse roles in the carrier transport, absorber, and interfacial layers of PSCs. We thoroughly examine advances in defect passivation, energy band alignment, perovskite crystallinity, device stability, and broader light absorption. In particular, novel approaches to enhance the photoelectric conversion efficiency (PCE) of quantum dot-enhanced perovskite solar cells are highlighted. Lastly, based on a comprehensive overview, we provide a forward-looking outlook on advanced quantum dot fabrication and its impact on enhancing the photovoltaic performance of solar cells. This review offers insights into fundamental mechanisms that endorse quantum dots for improved PSC performance, paving the way for further development of quantum dot-integrated PSCs.

Two-dimensional transition metal dichalcogenides (2D TMDCs) can be combined with organic semiconductors to form hybrid van der Waals heterostructures. Specially, non-fullerene acceptors (NFAs) stand out due to their excellent absorption and exciton diffusion properties. Here, we couple monolayer tungsten diselenide (ML-WSe₂) with two well performing NFAs, ITIC, and IT-4F (fluorinated ITIC) to achieve hybrid architectures. Using steady state and time resolved spectroscopic techniques, we reveal sub-picosecond free charge generation in the heterostructure of ML-WSe₂ with ITIC, where however, bimolecular recombination of spin uncorrelated charge carriers with possible contributions from geminate charge recombination cause rapid formation of low-lying triplet (T₁) states in ITIC. Importantly, this unwanted process is effectively suppressed when the fluorinated derivative of ITIC, IT-4F, is deposited on ML-WSe₂. We observe a similar scenario when replacing the ML-TMDC with copper thiocyanate (CuSCN) as the hole acceptor meaning that triplet state formation is not driven by the spin-orbit coupling of ML-WSe₂. From ab initio calculations based on density functional theory, we interpret the high triplet formation in the ML-WSe₂/ITIC hybrid bilayer due to changes in the nature and energies of the interfacial charge transfer (CT) levels. Our results highlight the delicate balance between excitons and charges in such inorganic/NFA heterostructures.

Dynamic responsive structural colored materials have drawn increased consideration in a wide range of applications, such as colorimetric sensors and high-safety tags. However, the sophisticated interactions among the individual responsive parts restrict the advanced design of multimodal responsive photonic materials. Inspired by stimuli-responsive color change in chameleon skin, a simple and effective photo-crosslinking strategy is proposed to construct hydroxypropyl cellulose (HPC) based hydrogels with multiple responsive structured colors. By controlling UV exposure time, the structural color of HPC hydrogels can be effectively controlled in a full-color spectrum. At the same time, HPC hydrogels showcase temperature and mechanical dual-responsive structural colors. In particular, the microstructure of HPC hydrogels undergoes a transition from the chiral nematic phase to the nematic phase under the action of external stretching, leading to a significant reflection of circularly polarized light (CPL) to linearly polarized light (LPL). Given the diverse responsiveness exhibited by HPC hydrogels and their unique structural transition properties under external forces, we have explored their potential applications as dynamic anti-counterfeiting labels and optical skins. This work reveals the great possibility of using structural colored cellulose hydrogels in multi-sensing and optical displays, opening up a new path for the exploration of next-generation flexible photonic devices.

Given that optical thermometers are widely used due to their unique advantages, this study aims to address critical challenges in existing technologies, such as insufficient sensitivity, limited temperature measurement ranges, and poor signal recognition capabilities. Herein, we develop a thermometer based on the fluorescence intensity ratio (FIR) of Sb-doped Cs₂NaInCl₆ (Cs₂NaInCl₆:Sb). As the temperature increases from 203 to 323 K, the thermally induced transition from triplet to singlet self-trapped excitons (STEs) leads to enhanced 455 nm photoluminescence (PL) from singlet STE recombination. Thus, the FIR monotonically depends on temperature, allowing for temperature sensing with a high absolute sensitivity (S_A) of 0.0575 K^-1 and the maximum relative sensitivity (S_R) of 1.005% K^-1. We demonstrate that spatial temperature distribution can be measured by mapping the PL spectra, even with a transparent medium screening the target. Furthermore, blue emissive Cs₂NaInCl₆:Sb is mixed with yellow emissive Cs₂AgInCl₆:Sb with a thermal quenching feature. The fluorescence color of the mixture dramatically depends on temperature, enabling a user-friendly colorimetric temperature sensing. Therefore, two operational modes are proposed to meet various practical application demands.

Given extremely high porosity, aerogels have demonstrated remarkable advantages in serving as thermal insulation and wave-transparent materials. Unfortunately, their practical applications are greatly confined by their inherent fragility. The recent emergence of polymer aerogels presents an ideal platform for the development of flexible aerogel films. However, additional cross-linking agents are necessitated for constructing a robust structure, complicating the production process. Herein, we report a flexible aerogel film based on meta-aramid composites, inspired by the porous structure of penguin feathers. The intermolecular hydrogen bonds function as natural cross-linking agents. Their disruption results in the dissolution of meta-aramid fibers, while their reconstruction facilitates localized rearrangement of meta-aramid chains during the sol-gel process, generating closed nanopores. Furthermore, fluorinated hollow glass microspheres are filled, compressing the nanopores situated near the interface to 75-150 nm. This meets the critical threshold required by the Knudsen effect, decreasing the thermal conductivity to levels below that of ambient air. At an optimized doping ratio of 3 wt%, the thermal conductivity is 21.6 mW m^-1 K^-1, while achieving a low dielectric constant of 1.43. Simultaneously, aerogel films exhibit enhanced mechanical properties, and also show benefits of hydrophobicity, colorability, ultralightness, and flame retardancy, making themselves multifunctional materials suitable for practical applications.

Stretchable electromagnetic interference (EMI) shields with strain-insensitive EMI shielding and Joule heating performances are highly desirable to be integrated with wearable electronics. To explore the possibility of applying geometric design in elastomeric liquid metal (LM) composites and fully investigate the influence of LM geometry on stretchable EMI shielding and Joule heating, multifunctional wrinkle-structured LM/Ecoflex sandwich films with excellent stretchability are developed. The denser LM wrinkle enables not only better electrical conduction, higher shielding effectiveness (SE) and steady-state temperature, but also enhanced strain-stable far-field/near-field shielding performance and Joule-heating capability. More strikingly, compared to most previously reported stretchable EMI shields or electric heaters, the densely wrinkled film could achieve multidirectional strain-insensitive shielding behavior with slightly strain-enhanced or strain-invariant EMI SE under stretching parallel or perpendicular to the electric field of EM waves, as well as show ideal strain-insensitive Joule-heating behavior over a larger strain range of 250%. The current findings suggest an effective strategy for developing stretchable LM-based composites with strain-insensitive properties.

Circularly polarized luminescence (CPL) materials have developed rapidly in recent years due to their wide application prospects in fields like 3D displays and anti-counterfeiting. Utilizing energy transfer processes to transfer chirality has been proven as an efficient way to obtain CPL materials. However, the physics behind energy-transfer induced CPL is still not clear. Herein, in a well-designed heteronuclear Ce^III-Mn^II complex system [(Ce((R/S)-L)Br(μ-Br))₂]MnBr₄ [(R/S)-L = (2R,3R)- or (2S,3S)-2,3-dimethyl-1,4,7,10,13,16-hexaoxacyclooctadecane] with intra energy transfer from Ce^III to Mn^II, the luminescence dissymmetry factor of Mn^II obtained by excitation of Ce^III is around 10 times higher than that obtained by direct excitation of Mn^II, while the Ce^III center itself shows an almost negligible CPL. To address this unusual phenomenon, we proposed a new mechanism named structural relaxation chirality transfer (SRCT) where structural relaxation of the excited chiral donor amplified chirality transfer to the acceptor by intramolecular interactions. As an assistant proof, a mixture of Ce^III-Zn^II and La^III-Mn^II complexes with inter energy transfer showed no CPL amplification. These results will inspire more breakthroughs in the physics nature and development of energy-transfer induced CPL.

Adhesion-switchable ultralow-hysteresis polymer ionogels are highly demanded in soft electronics to avoid debonding damage and signal distortion, yet the design and fabrication of such ionogels are challenging. Herein, we propose a novel method to design switchable adhesive ionogels by using binary ionic solvents with two opposite-affinity ionic components. The obtained ionogels exhibit moisture-induced phase separation, facilitating switchable adhesion with a high detaching efficiency (>99%). Moreover, before and after phase separation, the viscoelastic behavior of the ionogels is maintained in the rubbery plateau region within common frequency ranges with ultralow mechanical hysteresis (∼3%) under large strain, enabling accurate and stable strain and pressure sensing. Accordingly, the ionogel films can be used as functional elements in a smart clamp to realize flytrap-like selective activation, based on high sensitivity to the vibration intensity from the targeted prey. This work may inspire future research on the development of advanced soft electronics.

Developing hydrogels with high conductivity and toughness via a facile strategy is important yet challenging. Herein, we proposed a new strategy to develop conductive hydrogels by growing metal dendrites. Water-soluble Sn²⁺ ions were soaked into the gel and then converted to Sn dendrites via an electrochemical reaction; the excessive Sn²⁺ ions were finally removed by water dialysis, accompanied by dramatic shrinkage of the gel. Based on in situ transformation from metal ions to dendrites, the method integrated the advantages of ionic conductive fillers, such as LiCl (uniform dispersion), and electrical fillers, such as metal particles (high conductivity). Additionally, the morphology of metal dendrites combined advantages of 1D nanowires (large aspect ratio of the branches) and 2D nanosheets (large specific surface area of the skeleton). The strategy was found to be effective across diverse gel systems (non-ionic, anionic, cationic and zwitterionic). The dense, highly conductive and branched Sn dendrites not only formed a conductive pathway but also interacted with the polymer network to transfer stress and dissipate energy. The resultant gel exhibited a high conductivity of 12.5 S m⁻¹, fracture energy of 1334.0 J m⁻², and fatigue threshold of 720 J m⁻². Additionally, the gel exhibited excellent sensitivity when used as a wearable strain sensor and bioelectrode. We believe this strategy offers new insights into the development of conductive hydrogels.