Smart hybrids of Zn2GeO4 nanoparticles and ultrathin g‐C3N4 layers (Zn2GeO4/g‐C3N4 hybrids) are realized by a facile solution approach, where g‐C3N4 layers act as an effective substrate for the ...nucleation and subsequent in situ growth of Zn2GeO4 nanoparticles. A synergistic effect is demonstrated on the two building blocks of Zn2GeO4/g‐C3N4 hybrids for lithium storage: Zn2GeO4 nanoparticles contribute high capacity and serve as spacers to isolate the ultrathin g‐C3N4 layers from restacking, resulting in expanded interlayer and exposed vacancies with doubly bonded nitrogen for extra Li‐ion storage and diffusion pathway; 2D g‐C3N4 layers, in turn, minimize the strain of particles expansion and prevent the formation of unstable solid electrolyte interphase, leading to highly reversible lithium storage. Benefiting from the remarkable synergy, the Zn2GeO4/g‐C3N4 hybrids exhibit highly reversible capacity of 1370 mA h g−1 at 200 mA g−1 after 140 cycles and excellent rate capability of 950 mA h g−1 at 2000 mA g−1. The synergistic effect originating from the hybrids brings out excellent electrochemical performance, and thus casts new light on the development of high‐energy and high‐power anode materials.
Smart hybrids of Zn2GeO4 nanoparticles and ultrathin g‐C3N4 layers are prepared, in which Zn2GeO4 nanoparticles are dispersed onto and intercalated into g‐C3N4 layers, thus isolating the ultrathin g‐C3N4 layers from restacking. The structural advantage of Zn2GeO4/g‐C3N4 hybrids conduces to synergistic lithium storage, resulting in highly reversible capacity, fine cycle performance, and excellent rate capability.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Electrowetting technique is an actuation method for manipulating position and velocity of fluids in the microchannels. By combining electrowetting technique and a freestanding mode triboelectric ...nanogenerator (TENG), we have designed a self-powered microfluidic transport system. In this system, a mini vehicle is fabricated by using four droplets to carry a pallet (6 mm × 8 mm), and it can transport some tiny object on the track electrodes under the drive of TENG. The motion of TENG can provide both driving power and control signal for the mini vehicle. The maximum load for this mini vehicle is 500 mg, and its highest controllable velocity can reach 1 m/s. Freestanding TENG has shown excellent capability to manipulate microfluid. Under the drive of TENG, the minimum volume of the droplet can reach 70–80 nL, while the tiny droplet can freely move on both horizontal and vertical planes. Finally, another strategy for delivering nanoparticles to the designated position has also been demonstrated. This proposed self-powered transport technique may have great applications in the field of microsolid/liquid manipulators, drug delivery systems, microrobotics, and human-machine interactions.
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IJS, KILJ, NUK, PNG, UL, UM
Efficient extraction of photogenerated charge carriers is of significance for acquiring a high efficiency for perovskite solar cells. In this paper, a systematic strategy for effectively engineering ...the charge extraction in inverted structured perovskite solar cells based on methylammonium lead halide perovskite (CH 3 NH 3 PbI 3−x Cl x ) is presented. Intentionally doping the chlorine element into the perovskite structure is helpful for obtaining a high open circuit voltage. The engineering is carried out by modifying the aluminium cathode with zirconium acetylacetonate, doping the hole transport layer of nickel oxide (NiO x ) with copper and using an advanced fluorine doped tin oxide (FTO) substrate. This improves the bandgap alignment of the whole device, and thus, is of great benefit for extracting the charge carriers by promoting the transport rate and reducing the trap states. Consequently, an optimized power conversion efficiency of 20.5% is realized. Insights into how to extract charge carriers efficiently with a minimum energy loss are discussed.
Given the threat of environmental degradation and land deterioration to conventional agriculture, modern greenhouse cultivation has attracted increasing attention as an effective alternative. ...However, the high energy consumption of greenhouse systems is concerning given the need to limit the environmental impact of human activities. The solar integration to agricultural greenhouse in the form of modern solar greenhouse has the potential to simultaneously respond to the declining availability of suitable land and the imperative for minimum emissions. In this review, an overview of China's progress towards the development of modern solar greenhouses, as well as the attempts to mitigate the effects of heat loss, shadowing, and poor light condition is presented. A promising prospect is shown by China's modern solar greenhouses at present levels of performances and costs exemplified by the photovoltaic (PV) greenhouses with a practicable payback period of less than 9 years. Additionally, application of advanced solar technology for better thermal storage, PV power generating and light utilization balance has been proved effective to further promote solar energy utilization in modern solar greenhouses.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The carrier lifetime and the doping property of the lead halide perovskites are essential factors determining their application in solar cells. Hence, these two factors of the perovskite (CH3NH3PbI3) ...film were managed by postannealing, and the underlying mechanisms governing their effects on the photovoltaic performance of the solar cells were investigated. The short carrier lifetime from electron-hole bimolecular recombination, corresponding to the fast decay of photoluminescence, is achieved in perovskite films annealed at high temperatures. The doping property of the perovskite varies from p-type, intrinsic to n-type with increasing annealing temperature. The short carrier lifetime and the intrinsic feature of the perovskite benefit for high open circuit voltage of the corresponding solar cells, whereas the n-type doped perovskite leads to the high photocurrent and efficiency. Through the management of the carrier lifetime and the doping property, highly efficient perovskite solar cells with conversion efficiency over 17% were prepared. These results provide new insights into the underlying relations between the perovskite properties and the device performance.
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IJS, KILJ, NUK, PNG, UL, UM
Trivalent Chromium Process (TCP) was developed as a promising conversion process aiming at enhancement of corrosion properties and adhesion of aluminium alloys. The alkaline etching and acid pickling ...are usually applied as surface pretreatments on aluminium alloys before TCP deposition in order to optimize their properties. In this work, the surface modifications of an Al-Cu-Li alloy (AA2050-T8) at different stages of pretreatment (alkaline degreasing and acid pickling) and subsequent TCP are investigated by X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry and scanning electron microscopy. The pretreatments leading to significant enrichments in Cu and less marked in Ag, show also a strong influence on the subsequent formation of TCP in comparison to the non-pretreated, polished AA2050-T8 alloy. A slight decrease in Li content is observed in the oxide layer after pretreatment and no Li is present in the outer TCP layer. A thicker TCP conversion coating (outer oxide) with less cracks is formed on the pretreated alloy surface than on the polished one. Moreover, a Cu enrichment is evidenced in the TCP layer of the pretreated sample, which results in enhanced cathodic activity of pretreated sample with reference to polished sample as demonstrated by linear sweep voltammetry.
Instability of the perovskite materials, especially in high humidity, is one of the major limitations that hinders the development of perovskite devices. Herein, to eliminate the degradation of ...perovskite solar cells in humid air, a water-resistant perovskite absorption layer is proposed by introducing a macrocycle-type cyclodextrin material (β-CD) into the films. The β-CD was proved to be capable of facilitating the crystallization of grains and enhancing the stability of the perovskite by forming supramolecular interactions with organic cations through the hydrogen bonding in the perovskite films. Consequently, the average efficiency of the PSCs remarkably increased from 16.19% to 19.98%. The champion solar cell even delivered an efficiency of 20.09%. The PSCs with β-CD exhibited superior long-term stability in ambient air without encapsulation, which retained 90% of the initial efficiency after continuous AM 1.5 illumination in ambient air with 80% humidity for 300 h.
The trap states and the intrinsic nature of polycrystalline organometallic perovskites cause carrier losses in perovskite solar cells (PSCs) through carrier recombination at the surface and ...subsurface of the perovskites, leading to lowered conversion efficiency. Herein, to reduce the carrier losses, an intelligent approach concerning surface passivation and interfacial doping of the perovskite is proposed by introducing an F4TCNQ interfacial layer. The trap states at the perovskite surface are efficiently suppressed, leading to a homogenous surface potential of perovskite, which avoids the surface carrier recombination. The Fermi level of the perovskite is shifted to its valence band by 0.2 eV, inducing an energy barrier for electron diffusion and contributing directly to a minimized carrier recombination at the subsurface of the perovskite film. Consequently, the performance of the PSCs is remarkably improved, with the average efficiency increased from 14.3 plus or minus 0.9% to 16.4 plus or minus 1.0% (with a maximum efficiency of 18.1%). Moreover, the PSCs with the dual function interfacial layer show enhanced long-term stability in ambient air without device encapsulation.
A highly transparent and efficient counter electrode was facilely fabricated using SiO2/poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT–PSS) inorganic/organic composite and used in ...bifacial dye-sensitized solar cells (DSCs). The optical properties of SiO2/PEDOT–PSS electrode can be tailored by the blending amount of SiO2 and film thickness, and the incorporation of SiO2 in PEDOT–PSS provides better transmission in the long wavelength range. Meanwhile, the SiO2/PEDOT–PSS counter electrode shows a better electrochemical catalytic activity than PEDOT–PSS electrode for triiodide reduction, and the role of SiO2 in the catalytic process is investigated. The bifacial DSC with SiO2/PEDOT–PSS counter electrode achieves a high power conversion efficiency (PCE) of 4.61% under rear-side irradiation, which is about 83% of that obtained under front-side irradiation. Furthermore, the PCE of bifacial DSC can be significantly increased by adding a reflector to achieve bifacial irradiation, which is 39% higher than that under conventional front-side irradiation.
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IJS, KILJ, NUK, PNG, UL, UM
Abstract The commercialization of perovskite solar cells is badly limited by stability, an issue determined mainly by perovskite. Herein, inspired by a natural creeper that can cover the walls ...through suckers, we adopt polyhexamethyleneguanidine hydrochloride as a molecular creeper on perovskite to inhibit its decomposition starting from the annealing process. The molecule possesses a long-line molecular structure where the guanidinium groups can serve as suckers that strongly anchor cations through multiple hydrogen bonds. These features make the molecular creeper can cover perovskite grains and inhibit perovskite decomposition by suppressing cations’ escape. The resulting planar perovskite solar cells achieve an efficiency of 25.42% (certificated 25.36%). Moreover, the perovskite film and device exhibit enhanced stability even under harsh damp-heat conditions. The devices can maintain >96% of their initial efficiency after 1300 hours of operation under 1-sun illumination and 1000 hours of storage under 85% RH, respectively.
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