Converting and storing solar energy and releasing it on demand by using solar flow batteries (SFBs) is a promising way to address the challenge of solar intermittency. Although high solar-to-output ...electricity efficiencies (SOEE) have been recently demonstrated in SFBs, the complex multi-junction photoelectrodes used are not desirable for practical applications. Here, we report an efficient and stable integrated SFB built with back-illuminated single-junction GaAs photoelectrode with an n-p-n sandwiched design. Rational potential matching simulation and operating condition optimization of this GaAs SFB lead to a record SOEE of 15.4% among single-junction SFB devices. Furthermore, the TiO
protection layer and robust redox couples in neutral pH electrolyte enable the SFB to achieve stable cycling over 408 h (150 cycles). These results advance the utilization of more practical solar cells with higher photocurrent densities but lower photovoltages for high performance SFBs and pave the way for developing practical and efficient SFBs.
The surface chemistry of colloidal quantum dots (CQD) play a crucial role in fabricating highly efficient and stable solar cells. However, as‐synthesized PbS CQDs are significantly off‐stoichiometric ...and contain inhomogeneously distributed S and Pb atoms at the surface, which results in undercharged Pb atoms, dangling bonds of S atoms and uncapped sites, thus causing surface trap states. Moreover, conventional ligand exchange processes cannot efficiently eliminate these undesired atom configurations and defect sites. Here, potassium triiodide (KI3) additives are combined with conventional PbX2 matrix ligands to simultaneously eliminate the undercharged Pb species and dangling S sites via reacting with molecular I2 generated from the reversible reaction KI3 ⇌ I2 + KI. Meanwhile, high surface coverage shells on PbS CQDs are built via PbX2 and KI ligands. The implementation of KI3 additives remarkably suppresses the surface trap states and enhances the device stability due to the surface chemistry optimization. The resultant solar cells achieve the best power convention efficiency of 12.1% and retain 94% of its initial efficiency under 20 h continuous operation in air, while the control devices with KI additive deliver an efficiency of 11.0% and retains 87% of their initial efficiency under the same conditions.
Ligand exchange is performed on PbS colloidal quantum dots using conventional PbX2 ligands and KI3 additives via a facile one‐step process, which simultaneously eliminate the undesirable sites and efficiently passivate the surface. The resulting solar cells achieve a power conversion efficiency of 12.1%.
Graphitic carbon nitrides (g-C3N4) with unique physicochemical properties are promising candidates for photocatalysis applications. However, pristine g-C3N4 often suffers from narrow absorption ...ranges and high carrier recombination rates, which result in mediocre catalytic performance. In this work, we prepare novel sulfur-doped high nitrogen containing carbon nitrides, C3N5 (SCNs), with a combined thiadiazole, triazole, and triazine framework by facile self-assembly of 5-amino-1,3,4-thiadiazole-2-thiol (5-ATDT). Their structural, morphological, and optical properties, and photocatalytic activities are investigated in detail. From density functional theory calculations and spectroscopic characterization studies, we construct thermodynamically stable molecular structures of SCNs composed of one triazole and two triazine moieties with small ratios of thiadiazole on the edge, in which the sulfur atoms are ionically connected with carbon/nitrogen atoms and gradually detached on increasing the calcination temperatures. Remarkably, the resultant SCNs exhibit a significantly enhanced H2-generation rate of 486 μmol g−1 h−1, about 60% higher than the average value derived from typical g-C3N4 synthesised by conventional precursors thanks to the enlarged light absorption range and enhanced charge carrier transfer rate. Our work provides a unique approach for designing novel sulfur-doped carbon nitrides with unprecedented functionalities.
Abstract Rechargeable zinc batteries are promising choices for eco‐friendly, safe and cost‐effective energy storage solutions. However, their commercial adoption faces challenges such as low ...Coulombic efficiency (CE) and poor reversibility of Zn anodes. To address these issues, a new green electrolyte based on N,N'‐Dimethylpropyleneurea (DMPU) has been developed, affording a robust, dendrite‐free Zn anode with over 5000 h of cycle stability and a high average CE of 98.49%. Zn anode in DMPU‐electrolyte significantly outperforms aqueous electrolyte with 67 times longer cycle life, demonstrating excellent anode stability. Moreover, ultra‐stable Zn anode in DMPU‐electrolyte cycled for over 10 000 cycles at 1.0 mA cm −2 showcases excellent reversibility. The Dimethylpropyleneurea‐triflate anion generated solid electrolyte interphase enables homogeneous and rapid Zn 2+ ‐diffusion at the electrode interface, leading to a structured hexagonal Zn deposit. Furthermore, as electrolyte additive, DMPU significantly stabilizes Zn anode at severe conditions (5.0 and 10.0 mA cm −2 ) along with remarkable enhancement in CE (99.12%). This study offers valuable insights into the development of hybrid and organic electrolytes to advance Zn battery technology.
Highlights
Research progress on inorganic perovskites quantum dots is reviewed from three aspects: physical properties, synthesis approaches, and electronic applications.
Inorganic perovskite quantum ...dots have been exploited as either the active layers or the additives in high-performance transistors and memories.
Challenges and outlook on future advancement of perovskites quantum dots-based electronics are elaborated.
Metal halide perovskites have generated significant attention in recent years because of their extraordinary physical properties and photovoltaic performance. Among these, inorganic perovskite quantum dots (QDs) stand out for their prominent merits, such as quantum confinement effects, high photoluminescence quantum yield, and defect-tolerant structures. Additionally, ligand engineering and an all-inorganic composition lead to a robust platform for ambient-stable QD devices. This review presents the state-of-the-art research progress on inorganic perovskite QDs, emphasizing their electronic applications. In detail, the physical properties of inorganic perovskite QDs will be introduced first, followed by a discussion of synthesis methods and growth control. Afterwards, the emerging applications of inorganic perovskite QDs in electronics, including transistors and memories, will be presented. Finally, this review will provide an outlook on potential strategies for advancing inorganic perovskite QD technologies.
Contact engineering has been the central issue in the context of high-performance field-effect transistors (FETs) made of atomic thin transition metal dichalcogenides (TMDs). Conventional metal ...contacts on TMDs have been made on top via a lithography process, forming a top-bonded contact scheme with an appreciable contact barrier. To provide a more efficient pathway for charge injection, an end-bonded contact scheme has been proposed, in which covalent bonds are formed between the contact metal and channel edges. Yet, little efforts have been made to realize this contact configuration. Here, we bridge this gap and demonstrate seeded growth of end-bonded contact with different TMDs by means of chemical vapor deposition (CVD). Monolayer WSe2 FETs with a CVD-grown channel and end contacts exhibit improved performance metrics, including an on-current density of 30 μA/μm, a hole mobility of 90 cm2/V·s, and a subthreshold swing of 94 mV/dec, an order of magnitude superior than those of top-contact FET counterparts that share the same channel material. A fundamental NOT logic gate constructed using top-gated and end-bonded WSe2 and MoS2 FETs is also demonstrated. Calculations using density functional theory indicate that the superior device performance stems mainly from the stronger metal–TMD hybridization and substantial gap states in the end-contact configuration.
Neuromorphic vision sensors have been extremely beneficial in developing energy-efficient intelligent systems for robotics and privacy-preserving security applications. There is a dire need for ...devices to mimic the retina's photoreceptors that encode the light illumination into a sequence of spikes to develop such sensors. Herein, we develop a hybrid perovskite-based flexible photoreceptor whose capacitance changes proportionally to the light intensity mimicking the retina's rod cells, paving the way for developing an efficient artificial retina network. The proposed device constitutes a hybrid nanocomposite of perovskites (methyl-ammonium lead bromide) and the ferroelectric terpolymer (polyvinylidene fluoride trifluoroethylene-chlorofluoroethylene). A metal-insulator-metal type capacitor with the prepared composite exhibits the unique and photosensitive capacitive behavior at various light intensities in the visible light spectrum. The proposed photoreceptor mimics the spectral sensitivity curve of human photopic vision. The hybrid nanocomposite is stable in ambient air for 129 weeks, with no observable degradation of the composite due to the encapsulation of hybrid perovskites in the hydrophobic polymer. The functionality of the proposed photoreceptor to recognize handwritten digits (MNIST) dataset using an unsupervised trained spiking neural network with 72.05% recognition accuracy is demonstrated. This demonstration proves the potential of the proposed sensor for neuromorphic vision applications.
Solar‐driven photothermal water evaporation is considered an elegant and sustainable technology for freshwater production. The existing systems, however, often suffer from poor stability and ...biofouling issues, which severely hamper their prospects in practical applications. Conventionally, photothermal materials are deposited on the membrane supports via vacuum‐assisted filtration or dip‐coating methods. Nevertheless, the weak inherent material‐membrane interactions frequently lead to poor durability, and the photothermal material layer can be easily peeled off from the hosting substrates or partially dissolved when immersed in water. In the present article, the discovery of the incorporation of borophene into cellulose nanofibers (CNF), enabling excellent environmental stability with a high light‐to‐heat conversion efficiency of 91.5% and water evaporation rate of 1.45 kg m−2 h−1 under simulated sunlight is reported. It is also demonstrated that borophene papers can be employed as an excellent active photothermal material for eliminating almost 100% of both gram‐positive and gram‐negative bacteria within 20 min under three sun irradiations. The result opens a new direction for the design of borophene‐based papers with unique photothermal properties which can be used for the effective treatment of a wide range of wastewaters.
A novel borophene‐embedded cellulose paper is fabricated by incorporating two‐dimensional borophene nanosheets inside the cellulose fiber structure. The borophene paper exhibits outstanding absorption properties, featuring excellent stability and mechanical properties for photothermal water evaporation and bacterial killing applications.
Hybrid halide perovskites have emerged as highly promising photovoltaic materials because of their exceptional optoelectronic properties, which are often optimized via compositional engineering like ...mixing halides. It is well established that hybrid perovskites undergo a series of structural phase transitions as temperature varies. In this work, the authors find that phase transitions are substantially suppressed in mixed‐halide hybrid perovskite single crystals of MAPbI3‐xBrx (MA = CH3NH3+ and x = 1 or 2) using a complementary suite of diffraction and spectroscopic techniques. Furthermore, as a general behavior, multiple crystallographic phases coexist in mixed‐halide perovskites over a wide temperature range, and a slightly distorted monoclinic phase, hitherto unreported for hybrid perovskites, is dominant at temperatures above 100 K. The anomalous structural evolution is correlated with the glassy behavior of organic cations and optical phonons in mixed‐halide perovskites. This work demonstrates the complex interplay between composition engineering and lattice dynamics in hybrid perovskites, shedding new light on their unique properties.
Structural phase transitions are found to be substantially suppressed in mixed‐halide hybrid perovskites of MAPbI2Br and MAPbIBr2 (MA = CH3NH3+), because of the glassy behavior of organic cations and optical phonons. A slightly distorted monoclinic phase is dominant and coexists with multiple crystallographic phases over a wide temperature range.
Abstract
Metal halide perovskites can be readily synthesized, they exhibit tunable physical properties and excellent performance, and they are heavily studied optoelectronic materials. Compared to ...the typical three-dimensional perovskites, morphological-level one-dimensional (1D) nanostructures enable charge transport and photon propagation with low exciton binding energies and long charge-carrier diffusion lengths, while molecular-level 1D nanostructures exhibit good compositional and structural flexibilities, highly tunable bandgaps, strong quantum confinement effects, and excellent ambient stabilities. The 1D natures of these emerging halide perovskites enhance the performance of optoelectronic devices. Herein, we highlight recent progress realized in the syntheses and characterizations of both morphological- and molecular-level 1D halide perovskites with tunable structures, compositions, and properties, as well as their photovoltaic, light-emission, and photodetection applications. In addition, current challenges, future prospects, and promising research directions are discussed to provide guidance in advancing the field of 1D perovskites.
PDF
