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Tuning the composition of perovskites to approach the ideal bandgap raises the single-junction Shockley-Queisser efficiency limit of solar cells. The rapid development of narrow-bandgap formamidinium lead triiodide-based perovskites has brought perovskite single-junction solar cell efficiencies up to 26.1%. However, such compositional engineering route has reached the limit of the Goldschmidt tolerance factor. Here, we experimentally demonstrate a resonant perovskite solar cell that produces giant light absorption at the perovskite band edge with tiny absorption coefficients. We design multiple guide-mode resonances by momentum matching of waveguided modes and free-space light via Brillouin-zone folding, thus achieving an 18-nm band edge extension and 1.5 mA/cm 2 improvement of the current. The external quantum efficiency spectrum reaches a plateau of above 93% across the spectral range of ~500 to 800 nm. This resonant nanophotonics strategy translates to a maximum EQE-integrated current of 26.0 mA/cm 2 which is comparable to that of the champion single-crystal perovskite solar cell with a thickness of ~20 μm. Our findings break the ray-optics limit and open a new door to improve the efficiency of single-junction perovskite solar cells further when compositional engineering or other carrier managements are close to their limits. Further extending the band edge of perovskite approaching the ideal bandgap of single-junction solar cell is essential to improve device efficiency. Here, the authors integrate optical resonances with perovskite solar cells to extend the band edge, achieving EQE-integrated current of 26.0 mA/cm 2 .

Due to the large chemical composition and bandgap tunability of both perovskite and organic semiconductors, perovskite/organic tandem solar cells are attractive for next-generation thin-film photovoltaics. However, their efficiency is limited by the open-circuit voltage loss of wide-bandgap perovskite subcells and the non-ideal interconnecting layers. Here we report that the passivation of nickel oxide hole-transporting layers with benzylphosphonic acid leads to the suppression of interfacial recombination, boosting the voltage up to 1.26 V in a 1.79-eV-bandgap perovskite subcell. Then, we develop an optimized interconnecting layer structure based on a 4-nm-thick sputtered indium zinc oxide layer inserted between organic bathocuproine and molybdenum oxide with enhanced electrical properties and transmittance in the near-infrared region. Through these improvements, we achieve a maximum efficiency of 23.60% (22.95% certified) in the perovskite/organic tandem solar cell. In addition, the tandem device retained 90% initial efficiency after 500 h maximum power point tracking under continuous one sun illumination. The efficiency of perovskite/organic tandem solar cells is limited by losses in the open-circuit voltage and at the interconnecting layer. Now, Chen et al. develop a defect passivation strategy and a thin indium zinc oxide interlayer which lead to an efficiency as high as 23.6%.

In the context of algorithm selection, the careful design of benchmark functions and problem instances plays a pivotal role in evaluating the performance of optimization methods. Traditional benchmark functions have been criticized for their limited resemblance to real-world problems and insufficient coverage of the problem space. Exploratory landscape analysis (ELA) offers a systematic framework for characterizing objective functions, based on quantitative landscape features. This study proposes a method for generating benchmark functions tailored to single-objective continuous optimization problems with boundary constraints using predefined ELA feature vectors to guide their construction. The process begins with the creation of random decision variables and corresponding objective values, which are iteratively adjusted using the covariance matrix adaptation evolution strategy (CMA-ES) to ensure alignment with a target ELA feature vector within a specified tolerance. Once the feature criteria are met, the resulting topological map point is used to train a neural network to produce a surrogate function that retains the desired landscape characteristics. To validate the proposed approach, functions from the well-known Black Box Optimization Benchmark (BBOB) suite are replicated, and novel functions are generated with unique ELA feature combinations not found in the original suite. The experiment results demonstrate that the synthesized landscapes closely resemble their BBOB counterparts and preserve the consistency of the algorithm rankings, thereby supporting the effectiveness of the proposed approach.

Recently, few-shot learning has attracted significant attention in the field of video action recognition, owing to its data-efficient learning paradigm. Despite the encouraging progress, identifying ways to further improve the few-shot learning performance by exploring additional or auxiliary information for video action recognition remains an ongoing challenge. To address this problem, in this paper we make the first attempt to propose a relational action bank with semantic–visual attention for few-shot action recognition. Specifically, we introduce a relational action bank as the auxiliary library to assist the network in understanding the actions in novel classes. Meanwhile, the semantic–visual attention is devised to adaptively capture the connections to the foregone actions via both semantic correlation and visual similarity. We extensively evaluate our approach via two backbone models (ResNet-50 and C3D) on HMDB and Kinetics datasets, and demonstrate that the proposed model can obtain significantly better performance compared against state-of-the-art methods. Notably, our results demonstrate an average improvement of about 6.2% when compared to the second-best method on the Kinetics dataset.

The plate embedded with acoustic black hole (ABH) indentations is potential for structural vibration and noise control. This work focuses on the mid- and low-frequency performance of plates embedded with the array of ABH for energy focalization and vibration and noise suppression. Plates embedded with two-dimensional ABHs are modelled with detailed Finite Element models, and the power flow method is introduced to analyze the energy propagation characteristics arising from the ABH effect. Then, the distribution of average vibration power density along the ABH radius is studied. Next, the energy dissipation effects of the plate model embedded with the ABH array with two types of damping layers are investigated. Finally, the sound pressure levels of the ABH structure are calculated and discussed. This work is helpful to understand the characteristics of plates embedded with the ABH array in reducing vibration and noise radiation. Results show that the ABH array can realize more than 100 times energy focalization effect at some frequencies, which indicates a potential in vibration and noise control when coupled with damping materials.

Fusarium sacchari is a causal agent of sugarcane Pokkah boeng, an important fungal disease that causes a considerable reduction in yield and sugar content in susceptible varieties of sugarcane worldwide. Despite its importance, the fungal factors that regulate the virulence of this pathogen remain largely unknown. In our previous study, mapping of an insertional mutant defect in virulence resulted in the identification of a cutinase G-box binding protein gene, designated FsCGBP, that encodes a C2H2-type transcription factor (TF). FsCGBP was shown to localize in the nuclei, and the transcript level of FsCGBP was significantly upregulated during the infection process or in response to abiotic stresses. Deletion or silencing of FsCGBP resulted in a reduction in mycelial growth, conidial production, and virulence and a delay in conidial germination in the F. sacchari. Cutinase genes FsCUT2, FsCUT3, and FsCUT4 and the mitogen-activated protein kinase (MAPK) genes FsHOG1, FsMGV1, and FsGPMK1, which were significantly downregulated in ΔFsCGBP. Except for FsHOG1, all of these genes were found to be transcriptionally activated by FsCGBP using the yeast one-hybrid system in vitro. The deletion of individual cutinase genes did not result in any of the phenotypes exhibited in the ΔFsCGBP mutant, except for cutinase activity. However, disruption of the MAPK pathway upon deletion of FsMGV1 or FsGPMK1 resulted in phenotypes similar to those of the ΔFsCGBP mutant. The above results suggest that FsCGBP functions by regulating the MAPK pathway and cutinase genes, providing new insights into the mechanism of virulence regulation in F. sacchari.

Sugarcane leaf blight (SLB), a major fungal leaf disease of sugarcane (Saccharum spp.), has been attributed to Stagonospora tainanensis. In December 2020 and May 2021, signs of leaf blight were observed on sugarcane in the fields of Chongzuo City, in the Guangxi Province of China. Lesions on the leaves were characterized by yellow or dark red spots in the center. Fungal species were isolated, purified and subjected to pathogenicity evaluation on the sugarcane plants. An isolate that caused symptoms the same as those observed in the field was initially identified as S. tainanensis (Leptosphaeria taiwanensis, perfect state) based on its morphological characteristics both of asexual and sexual stages. Dark brown and nearly spherical pycnidia with conidia of long ellipsoidal, hyaline, one to four cells and 29.27 to 54.39 μm long and 9.03 to 16.12 μm wide were found on corn meal agar medium. Ascomata with asci of cylindrical to clavate, a short stipe and eight spores slightly constricted at the septum, with the size of the spore ranging from 36 to 44 μm long and 8.5 to 12 μm wide, were formed on the sugarcane-leaf-decoction saccharose agar medium. The identity of the species was further confirmed by rDNA ITS and TEF-1α sequencing. The optimal temperature for mycelial growth was 25 °C and the optimal pH was 6.0. The pathogen grew well in a medium with oats as the carbon source and yeast extract as the nitrogen source, but poorly in a medium with urea as the nitrogen source. This study is the first to identify the sugarcane leaf blight pathogen in Guangxi, and the first publication describing the biological characterization of S. tainanensis. The occurrence of sugarcane leaf blight should alert sugarcane breeders and plant pathologists to consider integrating control of this potentially important disease into the agenda of their breeding and disease control programs.

Perovskite bandgap tuning without quality loss makes perovskites unique among solar absorbers, offering promising avenues for tandem solar cells 1 , 2 . However, minimizing the voltage loss when their bandgap is increased to above 1.90 eV for triple-junction tandem use is challenging 3 – 5 . Here we present a previously unknown pseudohalide, cyanate (OCN − ), with a comparable effective ionic radius (1.97 Å) to bromide (1.95 Å) as a bromide substitute. Electron microscopy and X-ray scattering confirm OCN incorporation into the perovskite lattice. This contributes to notable lattice distortion, ranging from 90.5° to 96.6°, a uniform iodide–bromide distribution and consistent microstrain. Owing to these effects, OCN-based perovskite exhibits enhanced defect formation energy and substantially decreased non-radiative recombination. We achieved an inverted perovskite (1.93 eV) single-junction device with an open-circuit voltage ( V OC ) of 1.422 V, a V OC  × FF (fill factor) product exceeding 80% of the Shockley–Queisser limit and stable performance under maximum power point tracking, culminating in a 27.62% efficiency (27.10% certified efficiency) perovskite–perovskite–silicon triple-junction solar cell with 1 cm 2 aperture area. Triple-junction solar cells with cyanate in ultrawide-bandgap perovskites exhibit enhanced defect formation energy and substantially decreased non-radiative recombination.

Heterogeneity in transporting interfaces and perovskites poses a substantial challenge in improving the efficiency of perovskite solar cells from small to large scales, a key barrier to their commercial use. Here we find that the amorphous phases of self-assembling molecules (SAMs) can realize a more homogeneous perovskite growth. Hyperspectral analysis confirms a narrower and blueshifted photoluminescence peak distribution in perovskite/amorphous SAMs. Additionally, fluence-dependent time-resolved photoluminescence reveals a reduced trap-assisted recombination rate of 0.5 × 10 6  s −1 in amorphous-SAM-based perovskite films. This improvement translates to p–i–n structured perovskite solar cells achieving an efficiency of 25.20% (certified at 24.35%) over a one-square-centimetre area. These cells maintain nearly 100% efficiency after 600 h of 1-sun maximum power point tracking under the ISOS-L-1 protocol, and retain 90% of their initial efficiency after 1,000 h, as evaluated by the ISOS-T-2 protocol. Amorphous phases of self-assembling molecules employed as a hole-transporting layer in inverted perovskite solar cells contribute to homogeneous perovskite film growth, resulting in a power conversion efficiency of 25.20% (certified 24.35%) for one-square-centimetre area cells.

Halide perovskite solar cells (PSCs) have demonstrated exceptional potential in energy generation applications. The power conversion efficiency of lab-scale PSCs is reaching the Shockley-Queisser efficiency limit, though there are remaining challenges, such as stability and scalability issues, that await to be addressed for their commercialization. Interfaces of the PSCs play a crucial role in improving the devices’ stability. This thesis focuses on the optimization of the interfaces of the inverted p-i-n architecture perovskite solar cells, and treatments for the top and the buried interfaces of the solution processed PSCs are discussed. Nickel oxide (NiOx) is one of the most common hole transporting materials being adopted for the fabrication of inverted perovskite devices due to its outstanding intrinsic material stability and matched energy levels with the halide perovskite. However, it is notorious for its reaction with perovskite, which may eventually lead to degradation of the perovskite absorber. One key discussion of this thesis is on mitigating the redox reactions between the NiOx and the perovskite, and a few approaches have been adopted and discussed separately. The first approach is to suppress the formation of the reactive Ni3+ (nickel) species by adding Eu3+ (europium) during the synthesis of NiOx thin film. The Eu-doped NiOx is found to suppress the interfacial reactions and to reduce the defects. The second approach takes advantage of the inert nature of tin oxide (SnO2) with perovskite and incorporates Sb3+ (antimony) as a dopant, realizing a p-type Sb:SnO2 carrier transporting material. The combination of Sb:SnO2 with Me-4PACz self-assembled monolayer shows both improved device stability and power conversion efficiency as a result. For the top interface between perovskite and C60, the organic molecule methyldiammonium diiodide is introduced for interface passivation, resulting in reduced defect-assisted non-radiative recombination and improved open circuit voltage as well as device efficiency. A light management strategy with an optical filler layer is introduced to suppress optical interference and enhance the transmittance of semi-transparent devices. These interface treatments and strategies are universal and lead to efficient and stable PSCs, and the results helped progress perovskite photovoltaics and might lay guides for future endeavours of industrial entry.