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Verified CAS / Academic Author5 Decoded Studies

Prof. WANG Yunyan

Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University

Co-Affiliations:School of Metallurgy and Environment, Central South University, Changsha, China

Research Publications & English Decoded Briefs

Showing 5 publications
SCIENCE CHINA Materials2026DOI: 10.1007/s40843-025-3676-3

Pyromellitic diimide-mediated bulk passivation for efficient perovskite solar cells with low energy loss

Perovskite solar cells (PerSCs) have achieved remarkable efficiencies, yet their performance is limited by defect states and non-radiative recombination. Here, pyromellitic diimide (PD) is introduced as an additive to passivate bulk defects in perovskite films. PD forms hydrogen bonds with formamidinium (FA+) ions and coordinates with Pb2+ ions, effectively suppressing non-radiative recombination and reducing energy loss. The PD-treated perovskite films exhibit enhanced crystallinity and uniformity. Consequently, 1.55 eV PerSCs achieve a high open-circuit voltage (VOC) of 1.193 V and a power conversion efficiency (PCE) of 25.79%. Moreover, unencapsulated PD-treated devices retain 96% of their initial efficiency after 2000 h under nitrogen atmosphere, whereas control devices retain only 74%. Under ISOS-D-2I accelerated aging (65±5°C in N2), PD-treated devices show less than 5% PCE attenuation after 288 h, compared to ~30% for controls. This work provides a viable strategy for defect passivation in perovskite solar cells, enhancing both efficiency and stability.

SCIENCE CHINA Materials2026DOI: 10.1007/s40843-025-3623-y

Enhancing efficiency and brightness of deep-blue phosphorescent OLED enabled by a narrowband Pt(II) emitter

Organic light-emitting diodes (OLEDs) are an advanced technology for full-color displays, yet the low efficiency of blue OLEDs remains a critical bottleneck. Here, we report a new strategy to design robust Pt(II) emitters with enhanced molecular rigidity and increased locally excited character. The resulting Pt(II) emitter exhibits an extremely narrow emission spectrum peaking at 458.6 nm with a full-width at half-maximum (FWHM) of 16.0 nm and a small Huang-Rhys factor of 0.278, together with a high photoluminescence quantum efficiency of 95%. When doped into an OLED, the device emits at 464 nm with high color purity (FWHM = 19 nm) and achieves high external quantum efficiencies (EQEs) of 32.6%, 29.4%, and 26.9% at luminances of 123, 1000, and 5000 cd/m2, respectively. Notably, the device attains a record-high maximum brightness of 84,895 cd/m2 among reported deep-blue OLEDs with Commission Internationale de l'Éclairage (CIE) y-coordinate < 0.15. This work demonstrates one of the highest-performing deep-blue OLEDs reported to date, addressing the dual challenges of efficiency and brightness in this spectral region.

SCIENCE CHINA Materials2026DOI: 10.1007/s40843-025-3706-3

Interfacial charge redistribution in ultrafine ruthenium nanoparticle-decorated N-modified carbon catalysts accelerates oxygen redox for lithium-oxygen batteries

Aprotic lithium-oxygen (Li-O2) batteries are severely limited by slow cathode reaction kinetics and large polarization. Herein, we design and prepare a Mott-Schottky catalyst by uniformly embedding ultrafine Ru nanoparticles on nitrogen-doped carbon (Ru@NC) nanoflakes to accelerate oxygen redox kinetics of Li-O2 batteries. The Mott-Schottky effect of Ru@NC drives spontaneous electron rearrangement in the NC matrix and induces a strong built-in electric field at heterointerfaces, which accelerates the activation and conversion of oxygen intermediates. The obtained Ru@NC possesses rich Mott-Schottky heterointerfaces and defective carbon structures, which provide extensive adsorption and nucleation sites. More importantly, Ru@NC manifests moderate affinity for the intermediate LiO2, inducing formation of unique nanosheet-like Li2O2 with low Li2O2/cathode interfacial impedance, which further enhances oxidation kinetics. These enable the Li-O2 battery with Ru@NC to deliver a remarkably reduced polarization of 0.89 V, superior rate performance, and prolonged lifespan of over 200 cycles. This work will provide valuable guidelines for engineering advanced electrocatalysts for high-performance Li-O2 batteries and beyond.

Environmental Chemistry2026DOI: 10.7524/j.issn.0254-6108.2026031103

Speciation Analysis and Advanced Removal of Thallium from Washing Wastewater of Sintering Machine Head Ash

Sintering ash washing wastewater from steel plants is characterized by high salinity, high chloride content, high thallium load, and coexistence of multiple metals, posing significant treatment challenges. This study employed thermodynamic simulation to elucidate the speciation and transformation of thallium in such wastewater, and systematically investigated a combined process of sulfide precipitation coupled with coagulation-flocculation. The results showed that at pH 9–10, thallium predominantly existed as Tl+. Under oxidizing conditions, the stable complex anion [TlCl4]− dominated at pH < 8.1, while at pH > 8.1, a mixed system of solid Tl2O3 and dissolved TlClO3 coexisted. Under optimized conditions (pH 12, 2.0% thallium removal agent, 1.0% multi-effect auxiliary agent), the thallium concentration in the wastewater decreased from an initial 9.58 mg·L−1 to 4.31 μg·L−1, meeting the stringent discharge limit of ≤5 μg·L−1. Concurrent removal of Cu, Zn, and Cd was achieved. The primary removal mechanism was sulfide precipitation, with lattice substitution between Tl+ and K+ serving as an auxiliary pathway. This study provides a practicable technical route for advanced treatment of high-chloride, high-thallium industrial wastewater.

SCIENCE CHINA Materials2026DOI: 10.1007/s40843-026-4123-0

Entropy-Driven Modulation Enables Atomic-Level Interactions for High-Rate Capacity Cathode Materials in Rechargeable Aqueous Aluminum-Ion Batteries

Aqueous aluminum-ion batteries (AAIBs) are promising for large-scale energy storage due to safety, sustainability, and theoretical high capacity. However, sluggish electron/ion transport in conventional cathodes limits rate capability. Here, we first propose high-entropy engineering of metal oxides (HEOs) as cathodes in AAIBs, leveraging the 'cocktail effect' and abundant electron transport pathways to enhance rate-capacity. Atomic-level interactions between different metal atoms broaden the d-band with reduced electronic level degeneracy, facilitating rapid electron transport, achieving one of the best rate capabilities (119.4 mAh g−1 at 10.0 A g−1) among metal-oxide cathodes. The disordered layered oxides formed with a high-entropy framework alleviate electrostatic repulsion between aluminum ions and the fixed lattice, mitigating structural degradation and imparting excellent cycling stability (over 95.1 mAh g−1 after 500 cycles at 2.0 A g−1). The optimized HEO-Cr cathode (Fe0.6Co0.6Ni0.6Mn0.6Cr0.6O4) exhibits outstanding rate performance and cycling stability. DFT simulations and electrochemical tests reveal that multi-transition metal incorporation, bandgap narrowing, and unique lattice structure drastically enhance electron transport efficiency. The layered phase formed after cycling, based on a high-entropy framework, overcomes challenges from high charge density aluminum ions, significantly enhancing cycling stability. This work paves the way for high-performance AAIBs and other aqueous multivalent metal ion batteries by rationally designing high-entropy engineering.