Search

Wide‐bandgap (WBG) perovskite solar cells (PSCs) have garnered significant attention for their potential applications in tandem solar cells. However, their large open‐circuit voltage (VOC) deficit and serious photo‐induced halide segregation remain the main challenges that impede their applications. Herein, a post‐treatment strategy without thermal annealing is presented to form a 2D top layer of 2‐thiopheneethylammonium lead halide (n = 1) on WBG perovskites. This thermal annealing‐free post‐treatment method can more effectively passivate the defects of WBG methylamine (MA)‐free formamidinium/cesium lead iodide/bromide perovskite films and suppress photo‐induced perovskite phase segregation, as compared with the thermal annealing method that yields multi‐2D phases. The resulting opaque and semi‐transparent 1.66 eV‐bandgap perovskite solar cells deliver maximum power conversion efficiencies of 21.47% (a small VOC deficit of 0.43 V) and 19.11%, respectively, both of which are among the highest reports for inverted MA‐free WBG PSCs. Consequently, four‐terminal all‐perovskite tandem cells realize a remarkable efficiency of 26.64%, showing great promise for their applications in efficient multi‐junction tandem solar cells. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) represent a promising next‐generation photovoltaic technology considering their high efficiency and low cost. At the current stage, resolving the stability bottleneck is extremely urgent to realize PSCs' commercialization since the efficiencies of these cells are improved to a level comparable to that of crystalline silicon solar cells. Similar to other functional layers, a proper choice of the rear electrode atop the perovskite layer is equally important for achieving the device's long‐term stability. This topic has not been comprehensively reviewed before. Here, recent progress in the development of rear electrodes based on metals, carbon‐based materials, transparent conductive oxides, and conductive polymers is summarized, especially focusing on their different impacts on the device's long‐term stability and associated degradation mechanisms. In the context of practical applications, the impacts of rear electrode materials on the device's overall efficiency and cost‐effectiveness are also discussed. [ABSTRACT FROM AUTHOR]

Electrochemical ammonia synthesis (EAS) presents an attractive alternative to the Haber–Bosch process due to the benefits of energy saving, low carbon emission, environmental friendliness, and so on. However, the competing hydrogen evolution reaction (HER) severely limits the yield, selectivity, and current efficiency of NH3. Although the accumulation and self‐aggregation of active hydrogen (H*) are the primary causes of the competing HER, it also serves as the critical active species and intermediate for the multistep hydrogenation and deoxygenation processes. Therefore, the sensible regulation of the H* generation and consumption are essential for enhancing EAS performance. And it is significant to thoroughly review the current strategies for H* control. Herein, a comprehensive introduction of H* to provide a fundamental understanding of its role in electrochemical reactions, including generation, conversion, identification, and quantification protocols is first proposed. In addition, the role and control strategies of H* in EAS are carefully summarized with a particular focus on regulating H* generation and consumption to enhance the activity, selectivity, and Faradaic efficiency. Finally, the remaining challenges and perspectives are discussed. This critical review is intended to offer a profound understanding of the regulation of H* in electrochemical reactions and the development of EAS technology. [ABSTRACT FROM AUTHOR]

The electrocatalytic CO2 reduction reaction (CO2RR) has been considered a promising route toward carbon neutrality and renewable energy conversion. At present, most bismuth (Bi) based electrocatalysts are adopted to reduce CO2 to formate (HCOOH). However, the mechanism of different Bi nanostructures on the electrocatalytic performance requires more detailed exposition. Herein, a combined chemical replacement and electrochemical reduction process is reported to realize in situ morphology reconstruction from Bi@Bi2O3 nanodendrites (Bi@Bi2O3‐NDs) to Bi nanoflowers (Bi‐NFs). The Bi@Bi2O3‐NDs are proven to undergo a two‐step transformation process to form Bi‐NFs, aided by Bi2O2CO3 as the intermediate in KHCO3 solution. Extensive surface reconstruction of Bi@Bi2O3‐NDs renders the realization of tailored Bi‐NFs electrocatalyst that maximize the number of exposed active sites and active component (Bi0), which is conducive to the adsorption and activation of CO2 and accelerated electron transfer process. The as‐prepared Bi‐NFs exhibit a Faradaic efficiency (FEformate) of 92.3% at −0.9 V versus RHE and a high partial current density of 28.5 mA cm−2 at −1.05 V versus RHE for the electroreduction of CO2 to HCOOH. Moreover, the reaction mechanism is comprehensively investigated by in situ Raman analysis, which confirms that *OCHO is a key intermediate for the formation of HCOOH. [ABSTRACT FROM AUTHOR]

Antimicrobial photodynamic therapy (aPDT) has emerged as an appealing therapeutic option against biofilm infections. However, effectively penetrating the dense barrier of biofilm and anchoring bacteria to achieve biofilm elimination and wound healing under hypoxic environments remains a challenge for aPDT. Herein, three type I/II Hypocrellin B (HB)‐cationic photosensitizers (HB‐P, HB‐TP, and HB‐TTP) are designed based on a multi‐cationic long chains molecular engineering strategy. With an increasing number of introduced cations, the reactive oxygen species (ROS) production and bacterial‐anchoring abilities of HB‐cationic photosensitizers are greatly enhanced. Notably, HB‐TTP demonstrates higher type I/II aPDT activity and broad‐spectrum antibacterial properties. Furthermore, to effectively address the conundrum of healing biofilm‐infected wounds, a ROS‐responsive core‐shell microneedle (HB‐TTP&EGF@MN) is designed by biphasically integrating HB‐TTP and growth factor. When the microneedle penetrates biofilm, the shell quickly dissolves and releases HB‐TTP to achieve biofilm removal under laser irradiation. The core is subsequently degraded slowly in the presence of endogenous ROS within the wound, facilitating a sustained release of growth factor to promote wound tissue regeneration. This work not only provides an effective strategy for the rational design of efficient antimicrobial agents but also proposes innovative ideas for the development of controlled‐release pharmaceutical materials to synergize against biofilm infections. [ABSTRACT FROM AUTHOR]

Aqueous zinc ion batteries have received unprecedented attention owing to their superior safety and sustainability, yet their cycling stability especially at high current rates is greatly limited by the poor reversibility of Zn metal anodes, due to the delayed ion transport, severe water‐induced side reactions, and uncontrollable dendrites growth at electrolyte/electrode interface. Herein, a robust and multi‐scale functionally designed amorphous ZnWO4 (ZWO) artificial interphase that fully addresses the aforementioned issues, is proposed. The modified Zn anodes deliver remarkable stability, surpassing 3000 h of operation at a high current density of 20 mA cm−2 in symmetrical cells. Even under harsh conditions of 20 mA cm−2 and 10 mAh cm−2, the electrode demonstrates steady cycling for over 600 h with low overpotential. The excellent cycling stability and rate performance are mainly attributed to a range of collective functionalities of ZWO interphase, including short‐range and isotropic ion migration, superior ion‐screening capability, and a thermodynamically enhanced energy barrier for hydrogen evolution reaction (HER) during Zn plating. These findings highlight the significance of the multi‐scale functional interphase in overcoming key barriers associated with zinc anodes under high current density, offering a facile and insightful approach for achieving high‐performance Zn metal anodes. [ABSTRACT FROM AUTHOR]

Zinc‐ion batteries (ZIBs) have attracted wide attention due to their low redox potential, high capacity, and intrinsic safety. However, key issues such as zinc dendrite growth, corrosion, and passivation on zinc anode detrimentally affect the electrochemical performance. Herein, as proof of a concept of oligopeptide, glutathione with functional groups including –NH2 and −SH is introduced as an electrolyte additive to construct a multifunctional electrode–electrolyte interface layer on the zinc anode. A protonated amino group (NH3+) is formed, which prevents the adsorption of water molecules on the Zn anode, building a hydrophobic interface layer and thus attenuating corrosion. Moreover, the strong interaction between the −SH and the zinc allows glutathione molecules to be tightly anchored to the electrode surface, constructing a robust interface layer. Consequently, a long cycling life of nearly 3000 h at 1 mA cm−2 for the Zn||Zn symmetric battery is achieved, and a stable cycling life of 1600 h is demonstrated at 3 mA cm−2. Furthermore, Zn||activated carbon (AC) hybrid capacitor with the glutathione‐containing electrolyte runs stably for nearly 28 000 cycles at 5 A g−1, among the best results of reported Zn hybrid capacitors. [ABSTRACT FROM AUTHOR]

Local electron density manipulation can optimize the adsorption and desorption nature of catalysts leading to enhanced catalytic activity for water oxidation. Construction a Mott–Schottky barrier allows the electron transition in catalysts because of their different Fermi levels. Herein, a Pt@NiFc‐MOF Mott–Schottky heterojunction is constructed, in which electrons are transferred from NiFc‐MOF to Pt as triggered by the formed built‐in electric field at the interface. The as‐prepared Pt@NiFc‐MOF reveals exceptional performance toward the hydrazine oxidation reaction (HzOR), hydrogen evolution reaction (HER), and overall hydrazine splitting (OHzS) at ampere‐level current densities. The advanced nature of the configured Mott–Schottky heterojunction can also be further evidenced from a concept direct liquid N2H4/H2O2 fuel cell (Pt@NiFc‐MOF//Pt Net), yielding a maximum power density of 415.2 mW cm‒2 at 80°C and can work stably for 190 h at 500 mA cm‒2 (at 25°C). One more function of Pt@NiFc‐MOF is clarified as well, that is it can purify hydrazine‐rich wastewater from 718 to 6 ppb (less than the U.S. Environmental Protection Agency of 10 ppb) in 120 min at 500 mA cm‒2. This work represents a breakthrough in interface engineering of metal–organic frameworks (MOFs) toward industry‐level hydrogen generation and its beyond. [ABSTRACT FROM AUTHOR]

This study describes an amplification‐free, sequencing‐free platform (NanoPick‐array) for fast analysis of viral RNAs. The platform combines selective short‐cut of viral RNAs, cherry‐picking isolation of target genes, and micro‐arrayed discrete nanoimaging to enable the detection of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) at a concentration of 60 copies µL−1, a detection limit that is hardly achieved by Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)‐based methods without amplification, regardless of electrochemical or colorimetric approaches. Notably, the NanoPick‐array provides specific virus variant information with differentiation to single‐nucleotide genetic mutation. The avoidance of the amplification procedure gives direct quantification of viral copy number and reduces false positive results caused by amplicon contamination; the sequencing‐free viral variant specification significantly reduces the turn‐over time for the acquisition of a complete diagnostic viral picture within just 2 h. In a demonstration using clinical samples with a wide range of viral loads of cycle threshold (Ct) value ranging from 18 to 36, the technique achieves an overall accuracy of 89.7% viral detection and 100% accuracy for identifying all Delta variants. The viral detection accuracy is further tested to be 100% for the clinical samples with Ct values around or less than 28. [ABSTRACT FROM AUTHOR]

The delicate engineering of monovalent cations in perovskite material has led to continuous performance breakthroughs and stability improvement for the perovskite light‐emitting diodes (PeLEDs). However, the exact role of A‐site cations on the electroluminescence (EL) performance and degradation mechanism of PeLEDs has not been systematically answered yet. Herein, it is demonstrated that the most commonly used methylammonium cation (MA+) has an adverse effect on the electrochemical reaction at the interface between perovskite and metal‐oxide layer, leading to deteriorated EL performance as compared to that of the formamidinium cation (FA+)‐based perovskite. It reveals that the accelerated deprotonation process of MA+ under an electric field will aggravate the reaction between iodide and metal ion in oxide layer. The further substitution of a small portion of FA+ with inorganic cesium cation (Cs+) results in much enhanced crystallinity and enlarged crystal size, leading to an optimized peak external quantum efficiency of 21.3%. The ion migration process in the PeLEDs can be significantly suppressed with Cs+ incorporation, leading to a smaller roll‐off under large current density and an elongated half‐lifetime of 190.1 h under a current density of 20 mA cm‐2, representing one of the most stable PeLEDs based on 3D perovskite layer. [ABSTRACT FROM AUTHOR]

Single‐atom catalysts (SACs) have received widespread interest for their high atomic efficiency, enriched active sites, excellent catalytic performance, and low cost. However, the agglomeration of single metal atoms and the use of inactive additives for affixing powdery SACs on planar electrodes may reduce the density of active sites, diminish the charge transport to active sites, and thus suppress their performance. Herein, a series of metal–nitrogen–carbon single‐atom aerogels (M‐SAAs, M: Cu, Ni, Au, Ru) are synthesized via a universal strategy, in which the merits of metal organic frameworks and carbon aerogels are perfectly combined to prevent the agglomeration of single metal atoms and overcome the problem of poor electrical conductivity. The as‐prepared M‐SAAs can be directly employed as self‐supporting electrodes for the electrochemical dechlorination of 1,2‐dichloroethane, and outstanding activity and stability are observed. Significantly, the Cu‐SAA with abundant Cu−N4 sites shows an extraordinarily high ethylene production rate of 446 µmol h−1, with a selectivity of 99% and Faradaic efficiency of 64%. Moreover, theoretical calculations are performed to demonstrate the selectivity and activity of different metal active sites. This study provides a new strategy to exploit highly effective SACs and offers an intensive insight into the mechanism of electrochemical dechlorination reactions. [ABSTRACT FROM AUTHOR]

To couple hydrogen evolution reaction (HER) with urea oxidation reaction (UOR) is a promising approach to produce H2 with reduced energy consumption. However, the development of a low‐cost and high‐performance bifunctional electrocatalyst toward HER and UOR is still a challenge. In this work, oxygen‐incorporated nickel molybdenum phosphide nanotube arrays are synthesized on nickel foam (O‐NiMoP/NF) via electrodeposition accompanied with in‐situ template etching. Benefiting from the modulated electronic structure and the nanotube array architecture of O‐NiMoP, the self‐supporting O‐NiMoP/NF electrodes demonstrate highly efficient bifunctional catalytic activity toward HER and UOR. Particularly, in the HER and UOR (HER||UOR) coupled system for H2 production, a significantly reduced cell voltage of 1.55 V is obtained at the current density of 50 mA cm–2, which is about 300 mV lower than that of the conventional water electrolysis. Density functional theory calculations reveal that the remarkable HER and UOR activities originated from the Ni sites with the modulated electronic environment induced by Mo, P and O atoms, which facilitate the water dissociation during HER and balance the adsorption/desorption of the intermediates during UOR. The development of Ni‐based phosphides nanotube arrays as a bifunctional electrocatalyst in HER||OER system provides a new approach enabling energy‐saving H2 production. [ABSTRACT FROM AUTHOR]

Organic light emitting diodes (OLEDs) employing organic thin‐film based emitters have attracted tremendous attention due to their widespread applications in lighting and as displays in mobile devices and televisions. The novel thin‐film photovoltaic techniques using organic or organic–inorganic hybrid materials such as organic photovoltaics (OPVs) and perovskite solar cells (PSCs) have become emerging competitive candidates with regard to the traditional photovoltaic techniques on account of high‐efficiency, low‐cost, and simple manufacturing processing properties. However, OLEDs, OPVs, and PSCs are vulnerable to the undesired degradation induced by moisture and oxygen. To afford long‐term stability, a robust encapsulation technique by employing materials and structures that possess high barrier performance against oxygen and moisture must be explored and employed to protect these devices. Herein, the recent progress on specific encapsulation materials and techniques for three types of devices on the basis of fundamental understanding of device stability is reviewed. First, their degradation mechanisms, as well as, influencing factors are discussed. Then, the encapsulation technologies and materials are classified and discussed. Moreover, the advantages and disadvantages of various encapsulation technologies and materials coupled with their encapsulation applications in different devices are compared. Finally, the ongoing challenges and future perspectives of encapsulation frontier are provided. [ABSTRACT FROM AUTHOR]

The development of nanotheranostic agents that integrate diagnosis and therapy for effective personalized precision medicine has obtained tremendous attention in the past few decades. In this report, biocompatible electron donor-acceptor conjugated semiconducting polymer nanoparticles (PPor-PEG NPs) with light-harvesting unit is prepared and developed for highly effective photoacoustic imaging guided photothermal therapy. To the best of our knowledge, it is the first time that the concept of light-harvesting unit is exploited for enhancing the photoacoustic signal and photothermal energy conversion in polymer-based theranostic agent. Combined with additional merits including donor-acceptor pair to favor electron transfer and fluorescence quenching effect after NP formation, the photothermal conversion efficiency of the PPor-PEG NPs is determined to be 62.3%, which is the highest value among reported polymer NPs. Moreover, the as-prepared PPor-PEG NP not only exhibits a remarkable cell-killing ability but also achieves 100% tumor elimination, demonstrating its excellent photothermal therapeutic efficacy. Finally, the as-prepared water-dispersible PPor-PEG NPs show good biocompatibility and biosafety, making them a promising candidate for future clinical applications in cancer theranostics. [ABSTRACT FROM AUTHOR]

Cesium lead halide quantum dots (QDs) have tunable photoluminescence that is capable of covering the entire visible spectrum and have high quantum yields, which make them a new fluorescent materials for various applications. Here, the synthesis of CsPbX3 (X = Cl, Br, I, or mixed Cl/Br and Br/I) QDs by direct ion reactions in ether solvents is reported, and for the first time the synergetic effects of solvent polarity and reaction temperature on the nucleation and growth of QDs are demonstrated. The use of solvent with a low polarity enables controlled growth of QDs, which facilitates the synthesis of high-quality CsPbX3 QDs with broadly tunable luminescence, narrow emission width, and high quantum yield. A QD white LED (WLED) is demonstrated by coating the highly fluorescent green-emissive CsPbBr3 QDs together with red phosphors on a blue InGaN chip, which presents excellent warm white light emission with a high rendering index of 93.2 and color temperature of 5447 K, suggesting the potential applications of highly fluorescent cesium lead halide perovskite QDs as an alternative color converter in the fabrication of WLEDs. [ABSTRACT FROM AUTHOR]

NiO nanoflakes are created with a simple hydrothermal method on 3D (three-dimensional) graphene scaffolds grown on Ni foams by microwave plasma enhanced chemical vapor deposition (MPCVD). Such as-grown NiO-3D graphene hierarchical composites are then applied as monolithic electrodes for a pseudo-supercapacitor application without needing binders or metal-based current collectors. Electrochemical measurements impart that the hierarchical NiO-3D graphene composite delivers a high specific capacitance of ≈1829 F g−1 at a current density of 3 A g−1 (the theoretical capacitance of NiO is 2584 F g−1). Furthermore, a full-cell is realized with an energy density of 138 Wh kg−1 at a power density of 5.25 kW kg−1, which is much superior to commercial ones as well as reported devices in asymmetric capacitors of NiO. More attractively, this asymmetric supercapacitor exhibits capacitance retention of 85% after 5000 cycles relative to the initial value of the 1st cycle. [ABSTRACT FROM AUTHOR]

Free Radicals: A Biocompatible Free Radical Nanogenerator with Real-Time Monitoring Capability for High Performance Sequential Hypoxic Tumor Therapy (Adv. Funct. In article number 1903436, Jinfeng Zhang, Chun-Sing Lee, and co-workers develop a biocompatible free radicals nanogenerator for efficient hypoxic tumor therapy. Biocompatibility, oxygen-independent free radicals, photothermal therapy, real-time monitoring, tumor hypoxia. [Extracted from the article]

Hypoxic microenvironment severely reduces therapeutic efficacy of oxygen‐dependent photodynamic therapy in solid tumor due to the hampered cytotoxic oxygen radicals generation. Herein, a biocompatible nanoparticle (NP) is developed by combining bovine serum albumin, indocyanine green (ICG), and an oxygen‐independent radicals generator (AIPH) for efficient sequential cancer therapy, denoted as BIA NPs. Upon near‐infrared irradiation, the photothermal effect generated by ICG will induce rapid decomposition of AIPH to release cytotoxic alkyl radicals, leading to cancer cell death in both normoxic and hypoxic environments. Moreover, such nanosystem provides the highest AIPH loading capacity (14.9%) among all previously reported radical nanogenerators (generally from 5–8%). Additionally, the aggregation‐quenched fluorescence of ICG molecules in the NPs can be gradually released and recovered upon irradiation enabling real‐time drug release monitoring. More attractively, these BIA NPs exhibit remarkable anticancer effects both in vitro and in vivo, achieving 100% tumor elimination and 100% survival rate among 50 days treatment. These results highlight that this albumin‐based nanoplatform is promising for high‐performance cancer therapy circumventing hypoxic tumor environment and possessing great potential for future clinical translation. [ABSTRACT FROM AUTHOR]