Energy-related Materials

An emerging annelated thiophene of benzodithiophenedione (BDD) has exhibited its distinguished photovoltaic performance since its planar molecular structure, low-lying highest occupied molecular orbit (HOMO) level and well self-assembly property. In recent 7 years, BDD-based polymer donor have shown a rapid and incredible advancement by utilizing different acceptor materials. Considering the potentials of BDD-based materials, we summarize the most recent advances in the BDD-based photovoltaic materials and highlight the relations between BDD-based molecular structures and photovoltaic properties.

Metal halide perovskites are extraordinary defect-tolerant semiconductors. A unique structural aspect of perovskites is the octahedral coordination for (B-site) metal ions, unlike other semiconductors that exhibit tetrahedral coordination. This octahedral coordination helped to achieve lanthanide doping in halide perovskite nanocrystals in 2017. Fundamental understanding of material design, luminescence and quantum cutting phenomena in lanthanides (with focus on Yb³⁺) doped in CsPbX₃ (X = Cl, Br, I) and Cs₂AgInCl₆ nanocrystals are reported. Subsequently, these doped systems are applied for solar energy harvesting and lighting in both visible and near infrared region. This perspective article summarizes everything important that has happened so far in field and discusses about the future research directions.

Over the last decade, triboelectric nanogenerator (TENG) has been verified to be an effective way of converting daily mechanical energy into electric power or detecting various stimuli in the external environment. To promote the material researches in TENG, we introduce recent progresses in materials and material designs to improve the power generation and sensing performance. Also, we discuss on the future challenges and suggest possible approaches to solve the challenges.

Zn battery family with a long research history in the human electrochemical power supply has been revived and reevaluated in recent years. However, Zn anode in rechargeable batteries still lacks mature and reliable solutions to support the satisfactory cyclability required for the current versatile applications. In this paper, novel functional electrolytes, modified electrode-electrolyte interfaces and advanced electrode structures for addressing the bottlenecks encountered in rechargeable Zn anodes are reviewed, highlighting the mechanisms and open questions in practical applications.

We found high oxygen reduction reaction catalysts that are realized by ironphthalocyanine (FePc) derivatives, iron azaphthalocyanines (FeAzPcs) unimolecular layers (Fe AzUL) adsorbed on oxidized multiwall carbon nanotubes (oxMWCNTs). They showed superior ORR activities and durability than conventional FePc catalytic electrodes and commercial Pt/C. The Fe AzUL catalytic electrodes can be prepared by low-cost processing without pyrolysis, unlike other Pt-free catalytic electrodes, and are therefore promising catalytic electrode materials for applications, including polymer electrolyte fuel cells and metal–air batteries.

The Mo₂N-CoO hollow heterostructures are designed synthesis by the nitridation of a hollow Co-Mo-O precursor from controllable reaction of ZIF-67 (Co source and template) with Na₂MoO₄ (Mo source and OH- source). The catalyst exhibits good HER performance with an overpotential of 65 mV at 10 mA cm⁻² benefited from the combined virtues of hollow structure and heterojunction. The adjudication of MOFs makes current route promising toward the design of the transition metal-based catalyst for catalytic application.

To enhance supercurrent of iron-chalcogenide (FST) superconductor thin films, we induced nanostrain in FST thin films. The nanostrain was generated around nanoscale defects which were formed by the inserted a trace amount of oxide artificially inside FST matrix during the growth of FST thin film using sequential pulsed laser deposition. In particular, the critical current density (J_c) of the nanostrained FST thin films was significantly improved without dominant degradation of critical transition temperature.

Hybrid films with WO₃·H₂O nanoparticles-embedded chitosan on amorphous WO₃ films are newly designed for multi-functional devices with electrochromic energy storage performances.

A surface heterojunction is formed in the dandelion-like LTO, resulting in significant enhancement of the photocatalytic performance.

Achieving both high energy and high power densities in one hybrid energy-storage device is highly challenging, yet critically important for many applications. Here, the authors demonstrate that the inherent limitations of batteries and supercapacitors can be solved by developing a quaternary hybrid superstructure electrode using a high-energy biotemplate.

A series of FeO-CeO₂ nanocomposite catalysts (FeCe-x) were successfully fabricated by hydrogen reduction of hydroxide precursors at temperatures (x) between 200–600 °C. A FeCe-300 catalyst with a Fe:Ce ratio of 2-1 exhibited excellent performance for photothermal CO₂ hydrogenation to CO (CO selectivity = 99.87%, CO production rate 19.61 mmol h⁻¹ g_cat⁻¹, excellent stability). The FeO phase was effective in promoting the reverse water-gas shift (RWGS, CO₂ + H₂ → CO + H₂O). Catalysts prepared at higher reduction temperatures contained both Fe⁰ and FeO, with the Fe⁰ catalyzing the Sabatier reaction (CO₂ + 4H₂ → CH₄ + 2H₂O) and thus lowering FeCe-x catalyst selectivity to CO.

The light-trapping layer increases the travel distance of the light within the photoanode. By adapting light-trapping layers at dye-sensitized solar cells, we increased light absorption in the photoanode with pot shape light-trapping layer. Also we introduced three-dimensional angled array to maximize the photoanode projection area. By using these concepts we achieved 8.5% efficiency at submodule with 5% efficiency cells.

In this work, we prepared laser-scribed graphene/LiNi_1/3Mn_1/3Co_1/3O₂ (LSG/NMC) without binder and conductive agent as a new breakthrough cathode through DVD burner. The obtained LSG/NMC delivers not only high capacitance but also rate capability and cyclability. This is because the NMC spacer maximizes the effective area of LSG. This work demonstrates that LSG/NMC cathode can be regarded as a candidate for high-performance hybrid supercapacitor.

Precise control of colloidal-semiconductor-quantum-dots (CQD) assembly morphologies and the related carrier transport characteristics are vital to advance their utilisations. Each application requires different assembly types to exploit either the quantum confinement effect or the large surface-to-volume ratio. On-demand control of CQD-solids‘ morphology are demonstrated using variety of assembly methods. Employment of the electric-double-layer gating on varieties of CQD solids reveals their intrinsic carrier transport and accumulation characteristics. Compact superlattice structure shows high conductivity, and the hierarchical porous assembly exhibits high carrier accumulations. These flexibilities in assembly controls and characteristic tunings signify CQD versatilities as building blocks for different modern electronics.

Selective growth of ZnO nanorods/reduced graphene oxide composites via IR laser-induced reaction is developed for electrochemical devices. Optimized design of interdigitated supercapacitor electrodes can be achieved by programming of laser scanning lines. The integration of ZnO NRs on rGO improves supercapacitor performances due to synergistic effects of pseudo capacitance (ZnO) and electric double layer capacitance (graphene).

A sunlight management strategy in perovskite solar cells (PSCs) using silicon quantum dots (SiQDs) is proposed. Due to the reabsorption of visible light induced by SiQDs, the external quantum efficiency spectra of PSCs in a wide wavelength range of 360–760 nm is significantly improved, resulting in facilitated photocurrent collection and enhanced performance of SiQD-based PSCs.

Quantum dot LED (light-emitting diode) optimization through the control of charge carriers’ kinetics is presented using impedance spectroscopy. The mobility of charge carriers through each one of the layers provide a path to estimate the transition time of each one of the charge carriers toward the emitting layer. By focusing on thickness optimization of electron transferring layer we can control the transition time of charge carriers and maximize radiative recombination.