Improved charge extraction and wide spectral absorption promote power conversion efficiency of perovskite solar cells (PSCs). The state‐of‐the‐art carbon‐based CsPbBr3 PSCs have an inferior power ...output capacity because of the large optical band gap of the perovskite film and the high energy barrier at perovskite/carbon interface. Herein, we use alkyl‐chain regulated quantum dots as hole‐conductors to reduce charge recombination. By precisely controlling alkyl‐chain length of ligands, a balance between the surface dipole induced charge coulomb repulsive force and quantum tunneling distance is achieved to maximize charge extraction. A fluorescent carbon electrode is used as a cathode to harvest the unabsorbed incident light and to emit fluorescent light at 516 nm for re‐absorption by the perovskite film. The optimized PSC free of encapsulation achieves a maximum power conversion efficiency up to 10.85 % with nearly unchanged photovoltaic performances under 80 %RH, 80 °C, or light irradiation in air.
Chain gang: Regulating the alkyl‐chain length of quantum dots attached to inorganic CsPbBr3 perovskites maximizes charge extraction and transfer at the perovskite/carbon interface. The optimized inorganic CsPbBr3 perovskite solar cell (PSC) with C12 alkyl chain QDs yields an efficiency of up to 10.85 %.
The all‐inorganic CsPbBr3 perovskite solar cell (PSC) is a promising solution to balance the high efficiency and poor stability of state‐of‐the‐art organic–inorganic PSCs. Setting inorganic ...hole‐transporting layers at the perovskite/electrode interface decreases charge carrier recombination without sacrificing superiority in air. Now, M‐substituted, p‐type inorganic Cu(Cr,M)O2 (M=Ba2+, Ca2+, or Ni2+) nanocrystals with enhanced hole‐transporting characteristics by increasing interstitial oxygen effectively extract holes from perovskite. The all‐inorganic CsPbBr3 PSC with a device structure of FTO/c‐TiO2/m‐TiO2/CsPbBr3/Cu(Cr,M)O2/carbon achieves an efficiency up to 10.18 % and it increases to 10.79 % by doping Sm3+ ions into perovskite halide, which is much higher than 7.39 % for the hole‐free device. The unencapsulated Cu(Cr,Ba)O2‐based PSC presents a remarkable stability in air in either 80 % humidity over 60 days or 80 °C conditions over 40 days or light illumination for 7 days.
Cu(Cr,M)O2 nanocrystals with hole boosting by increasing the amount of interstitial oxygen enables them to be promising HTMs for all‐inorganic CsPbBr3 perovskite solar cells. The optimized device with Cu(Cr,Ba)O2 achieves a record efficiency as high as 10.79 %.
In the last decade, organic–inorganic hybrid lead-halide perovskites have been attracted tremendous attentions in the photovoltaic and optoelectronic community. Especially for perovskite solar cells ...(PSCs), the certified efficiency is up to as high as 25.5%, which has surpassed polycrystalline silicon solar cells and is comparable to the monocrystalline silicon solar cells. Till now, although the chemical instability of perovskite has been well alleviated by optimizing the lattice structure, the detrimental lead element is still a challenge for the commercialization process of PSC devices. To effectively resolve this issue, lead-free halide perovskites (LFHPs) have gained growing attentions recently due to their theoretically excellent optoelectronic properties and eco-friendly feature. With the aim to promote the development of LFHPs, in this review, we have mainly summarized the recent advancement of various LFHP materials and their applications in photovoltaics, light-emitting diodes (LEDs), photodetectors and other devices. Strategies for stabilization of perovskite lattice and performance improvement of optoelectronic devices including fabrication technology, compositional engineering and interfacial optimization are also emphasized. Finally, the potential and challenges of LFHPs are further discussed, providing new research direction for future development.
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•This review covers the hot top of Pb-free perovskites for optoelectronic devices.•Different elements can be employed to replace lead atoms in perovskite lattice.•Strategies for improving the performance and stability are summarized.•A brief outlook, including the remained issues and challenge is proposed.
The crystal distortion such as lattice strain and defect located at the surfaces and grain boundaries induced by soft perovskite lattice highly determines the charge extraction‐transfer dynamics and ...recombination to cause an inferior efficiency of perovskite solar cells (PSCs). Herein, the authors propose a strategy to significantly reduce the superficial lattice tensile strain by means of incorporating an inorganic 2D Cl‐terminated Ti3C2 (Ti3C2Clx) MXene into the bulk and surface of CsPbBr3 film. Arising from the strong interaction between Cl atoms in Ti3C2Clx and the under‐coordinated Pb2+ in CsPbBr3 lattice, the expanded perovskite lattice is compressed and confined to act as a lattice “tape”, in which the PbCl bond plays a role of “glue” and the 2D Ti3C2 immobilizes the lattice. Finally, the defective surface is healed and a champion efficiency as high as 11.08% with an ultrahigh open‐circuit voltage up to 1.702 V is achieved on the best all‐inorganic CsPbBr3 PSC, which is so far the highest efficiency record for this kind of PSCs. Furthermore, the unencapsulated device demonstrates nearly unchanged performance under 80% relative humidity over 100 days and 85 °C over 30 days.
Arising from the formation of strong PbCl bonding, chlorine terminated Ti3C2Clx MXenes are used as lattice “tape” to reduce the defects and release tensile strain located at interfaces and grain boundaries of CsPbBr3 perovskite film, achieving a champion efficiency up to 11.08% with an ultrahigh voltage of 1.702 V for CsPbBr3 perovskite solar cells.
Abstract
Realization of stable and industrial-level H
2
O
2
electroproduction still faces great challenge due large partly to the easy decomposition of H
2
O
2
. Herein, a two-dimensional ...dithiine-linked phthalocyaninato cobalt (CoPc)-based covalent organic framework (COF), CoPc-S-COF, was afforded from the reaction of hexadecafluorophthalocyaninato cobalt (II) with 1,2,4,5-benzenetetrathiol. Introduction of the sulfur atoms with large atomic radius and two lone-pairs of electrons in the C-S-C linking unit leads to an undulated layered structure and an increased electron density of the Co center for CoPc-S-COF according to a series of experiments in combination with theoretical calculations. The former structural effect allows the exposition of more Co sites to enhance the COF catalytic performance, while the latter electronic effect activates the 2e
−
oxygen reduction reaction (2e
−
ORR) but deactivates the H
2
O
2
decomposition capability of the same Co center, as a total result enabling CoPc-S-COF to display good electrocatalytic H
2
O
2
production performance with a remarkable H
2
O
2
selectivity of >95% and a stable H
2
O
2
production with a concentration of 0.48 wt% under a high current density of 125 mA cm
−2
at an applied potential of
ca
. 0.67 V
versus
RHE for 20 h in a flow cell, representing the thus far reported best H
2
O
2
synthesis COFs electrocatalysts.
"Intrinsic" strategies for manipulating the local electronic structure and coordination environment of defect-regulated materials can optimize electrochemical storage performance. Nevertheless, the ...structure–activity relationship between defects and charge storage is ambiguous, which may be revealed by constructing highly ordered vacancy structures. Herein, we demonstrate molybdenum carbide MXene nanosheets with customized in-plane chemical ordered vacancies (Mo1.33CTx), by utilizing selective etching strategies. Synchrotron-based X-ray characterizations reveal that Mo atoms in Mo1.33CTx show increased average valence of +4.44 compared with the control Mo2CTx. Benefited from the introduced atomic active sites and high valence of Mo, Mo1.33CTx achieves an outstanding capacity of 603 mAh·g−1 at 0.2 A·g−1, superior to most original MXenes. Li+ storage kinetics analysis and density functional theory (DFT) simulations show that this optimized performance ensues from the more charge compensation during charge–discharge process, which enhances Faraday reaction compared with pure Mo2CTx. This vacancy manipulation provides an efficient way to realize MXene's potential as promising electrodes.
Bandgap‐tunable mixed‐halide perovskite materials have attracted considerable interest because of their indispensability as top counterparts in tandem solar cells. However, the soft and disordered ...lattice always suffers from severe phase segregation under illumination, which is particularly susceptible to residual lattice strain. Herein, we report a strain regulation strategy by using alkenamides terminated Ti3C2Tx MXenes as an additive into perovskite precursor. Apart from the role of a template for grain growth to obtain high‐quality films, the stretchable alkyl chain promotes lattice shrinkage or expansion to form an elastic grain boundary to eliminate the spatially distributed stain and shut down ion migration channels. As a result, the all‐inorganic perovskite solar cells based on CsPbIBr2 and CsPbI2Br halides achieve prolonged device stability under harsh conditions and the best power conversion efficiencies up to 11.06% and 14.30%, respectively.
An elastic interface is fabricated to release residual lattice compressive and tensile strain of mixed‐halide inorganic CsPbIB2 perovskite film by using a stretchable alkenamides terminated Ti3C2Tx MXene as an additive, universally healing the defective lattices to suppress the nonradiative recombination and improving the efficiency and stability of wide‐bandgap perovskite solar cells.
Seawater electrolysis has great potential to generate clean hydrogen energy, but it is a formidable challenge. In this study, we report CoFe-LDH nanosheet uniformly decorated on a CuO nanowire array ...on Cu foam (CuO@CoFe-LDH/CF) for seawater oxidation. Such CuO@CoFe-LDH/CF exhibits high oxygen evolution reaction electrocatalytic activity, demanding only an overpotential of 336 mV to generate a current density of 100 mA cm
in alkaline seawater. Moreover, it can operate continuously for at least 50 h without obvious activity attenuation.
Researchers have recently focused on multimodal emotion recognition, but issues persist in recognizing emotions in multi-party dialogue scenarios. Most studies have only used text and audio modality, ...ignoring the video modality. To address this, we propose M2ER, a multimodal emotion recognition scheme based on multi-party dialogue scenarios. Addressing the issue of multiple faces appearing in the same frame of the video modality, M2ER introduces a method using multi-face localization for speaker recognition to eliminate the interference of non-speakers. The attention mechanism is used to fuse and classify different modalities. We conducted extensive experiments in unimodal and multimodal fusion using the multi-party dialogue dataset MELD. The results show that M2ER achieves superior emotion recognition in both text and audio modalities compared to the baseline model. The proposed method using speaker recognition in the video modality improves emotion recognition performance by 6.58% compared to the method without speaker recognition. In addition, the multimodal fusion based on the attention mechanism also outperforms the baseline fusion model.
High-purity cesium lead bromide (CsPbBr3) perovskite films are expected to promote the commercial manufacture of inorganic perovskite solar cells (PSCs). We present here a spray-assisted deposition ...of high-quality CsPbBr3 films in ambient air by spin-coating a PbBr2 layer and sequentially spraying CsBr multilayer to simplify the film fabrication technology. Upon optimizing spray deposition at four cycles, a high-purity CsPbBr3 phase is prepared and a maximized power conversion efficiency of 5.68% is achieved for the carbon-based inorganic PSC device. Furthermore, molybdenum disulfide quantum dots with an intermediate energy level are set at CsPbBr3/carbon interface to markedly increase charge extraction and to suppress electron-hole recombination, arising from the perovskite grain boundary passivation. Finally, the optimal inorganic PSC yields a stabilized efficiency of 6.80% under one sun illumination. Using this spray-assisted deposition method, this CsPbBr3 solar cell with an active area of 1 cm2 achieves an efficiency of 4.12%. The photovoltaic performances are relatively stable even upon 80% relative humidity over 700 h without encapsulation.
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•A spray-assisted method has been developed to fabricate CsPbBr3 films.•Impurity crystal phase of all-inorganic pervoskite is suppressed.•CsPbBr3 solar cell with a device area of 1 cm2 achieves an efficiency of 4.12%.•The optimal device shows excellent long-term stability over 700 h.
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