The surface area and structure of adsorbents are crucially important to its adsorption capacity. Herein, we focused on the correlation between the structures of 2D/3D materials and its adsorption properties by taking three kinds of cobalt−aluminum layered double hydroxide (CoAl-LDH) as adsorbents, including a 3D hierarchical flower-like hollow/solid sphere (FH/FS-CoAl) and 2D plate (P-CoAl). As expected, FH-CoAl showed the highest adsorption capacity (∼2189.23 mg/ g) for methyl orange (MO), benefiting from the highly accessible surface areas and more active sites of unique hollow structural characteristics inherited from the hierarchical flower-like hollow structures. Interestingly, compared with FS/FH-CoAl, P-CoAl exhibited the highest adsorption capacity enhancement times after being normalized with surface area, but displayed an inferior maximum adsorption capacity. The reasons could be mainly ascribed to (1) P-CoAl with 2D plate structures possessed more fully exposed active sites than FH-CoAl and (2) the compact and thick shell structure of the hollow structure made dye difficult to diffuse into the hollow interior. Moreover, the characterization analysis further confirmed that the electrostatic interaction, hydrogen bonding, and ion exchange were the main adsorption mechanisms for FH-CoAl and FS-CoAl, while electrostatic interaction was mainly an adsorption mechanism for P-CoAl. A deep understanding of synergistic modulation of surface area and structure effects of 2D/3D adsorbents will provide the opportunity for further enhancing the adsorption activity and offer a new pathway for design and optimization of advanced adsorbents in the near future.
commercial modules, respectively), excellent stability (>25 years guaranteed lifetime), low cost (<$0.30 per peak watt), and mature production lines. [1] Further improving power conversion efficiency (PCE) is the most effective way to reduce the cost of solar electricity. Nevertheless, the record PCE of single-junction Si solar cells is approaching its theoretical limit of 29.4%. [2] Tandem solar cells are widely regarded as the most promising strategy to break the Shockley-Queisser (S-Q) efficiency limit [3] since they can reduce the thermal relaxation energy loss of highenergy photons. [4] Theoretical calculations show that in double-junction Si-based tandem solar cells, the top cells should have a ≈1.7 eV bandgap (E g ) and tandem solar cells could achieve an efficiency limit of ≈45% [5] (Figure 1a).At present, III-V compounds and halide perovskites with a 1.7 eV bandgap are the most promising top cells for Si-based tandem solar cells (Figure 1a). [1b] Both of their single-junction and Si-based tandem solar cells have achieved >20% and >29% efficiency, respectively. [6] Nevertheless, they both suffer from obvious drawbacks. III-V photovoltaics are stable and highly efficient; however, they require sophisticated fabrication procedures and expensive fabrication equipment, leading to the prohibitive cost (≈$150 per peak watt) [7] and limited deployment. As for halide perovskites, they could be directly processed, either via solution processing or thermal evaporation, onto Si bottom solar cells without sacrificing device performance. Currently, two-terminal perovskite/Si tandem solar cells have achieved a record efficiency of 29.8%, but the long-term stability of perovskite top cells is not fully resolved. [8] Overall, what is the best choice as the top cell for Si-based tandem devices is still an open question in the field. It is thus highly valuable to explore new absorber materials for the top cell.Various semiconductors with ≈1.7 eV bandgap, such as amorphous-Si (a-Si), Zn x Cd 1-x Te, CuGaSe 2, and Sb 2 S 3 , have been considered as the alternative top cells over the past years (Table 1). A-Si sounds promising in terms of the simple chemical element, low fabrication cost, and large absorption coefficient. In 1990, an impressive efficiency of 15.04% has been achieved for two-terminal a-Si/c-Si tandem solar cells, but no progress was made since then due to its complex defects and the band tail state effect. [9] Wide bandgap Zn x Cd 1-x Te and CuGaSe 2 , originating from the commercial CdTe and Cu(In,Ga)Se 2 solar cells, Silicon-based tandem solar cells are regarded as one of the most feasible ways to break the single-junction Shockley-Queisser limit efficiency and further reduce the cost of solar electricity. Recently, wide-bandgap (≈1.7 eV) perovskite solar cells have drawn intense research interest as the top cell for Si-based tandem devices. Despite significant progress in device efficiency, the unsatisfactory stability of perovskites is still a huge concern. Besides halide perovskites, there are many in...
The efficiency of Sb2(S,Se)3 solar cells prepared by hydrothermal method break the bottleneck of 10% recently. However, limited by the black-box hydrothermal process, the important experimental details such as the...
Cadmium selenide (CdSe) solar cells have proven to be a remarkable potential top cell for a silicon-based tandem application. However, the defects and short carrier lifetimes of CdSe thin films greatly limit the solar cell performance. In this work, a Te-doped strategy is proposed to passivate the Se vacancy defects and increase the carrier lifetime of the CdSe thin film. The theoretical calculation helps to reveal the mechanism of nonradiative recombination of the CdSe thin film in depth. After Te-doping, the calculated capture coefficient of CdSe can be reduced from 4.61 × 10 −8 cm 3 s −1 to 2.32 × 10 −9 cm 3 s −1 . Meanwhile, the carrier lifetime of CdSe thin film is increased nearly 3fold from 0.53 to 1.43 ns. Finally, the efficiency of the Cd(Se,Te) solar cell is improved to 4.11%, about a relative 36.5% improvement compared to the pure CdSe solar cell. Both theoretical calculations and experiments prove that Te can effectively passivate bulk defects and improve the carrier lifetime of CdSe thin films, deserving further exploration to improve solar cell performance.
Selenium (Se) element is a promising light-harvesting material for solar cells because of the large absorption coefficient and prominent photoconductivity. However, the efficiency of Se solar cells has been stagnated for a long time owing to the suboptimal bandgap (> 1.8 eV) and the lack of a proper electron transport layer. In this work, we tune the bandgap of the absorber to the optimal value of Shockley–Queisser limit (1.36 eV) by alloying 30% Te with 70% Se. Simultaneously, ZnO electron transport layer is selected because of the proper band alignment, and the mild reaction at ZnO/Se0.7Te0.3 interface guarantees a good-quality heterojunction. Finally, a superior efficiency of 1.85% is achieved on ZnO/Se0.7Te0.3 solar cells. Graphical abstract
Short‐wave infrared detectors are increasingly important in the fields of autonomous driving, food safety, disease diagnosis, and scientific research. However, mature short‐wave infrared cameras such as InGaAs have the disadvantage of complex heterogeneous integration with complementary metal–oxide–semiconductor (CMOS) readout circuits, leading to high cost and low imaging resolution. Herein, a low‐cost, high‐performance, and high‐stability TexSe1–x short‐wave infrared photodiode detector is reported. The TexSe1–x thin film is fabricated through CMOS‐compatible low‐temperature evaporation and post‐annealing process, showcasing the potential of direct integration on the readout circuit. The device demonstrates a broad‐spectrum response of 300–1600 nm, a room‐temperature specific detectivity of 1.0 × 1010 Jones, a −3 dB bandwidth up to 116 kHz, and a linear dynamic range of over 55 dB, achieving the fastest response among Te‐based photodiode devices and a dark current density 7 orders of magnitude smaller than Te‐based photoconductive and field‐effect transistor devices. With a simple Si3N4 packaging, the detector shows high electric stability and thermal stability, meeting the requirements for vehicular applications. Based on the optimized TexSe1–x photodiode detector, the applications in material identification and masking imaging is demonstrated. This work paves a new way for CMOS‐compatible infrared imaging chips.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.