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Group V doping in CdSeTe device can improve power conversion efficiency (PCE) and device stability. Arsenic (As) incorporation into CdSeTe has been demonstrated via both in situ and ex situ techniques; however, optimizing the back contact for group V‐doped CdSeTe devices remains a critical challenge. Here, solution‐processed arsenic chalcogenides (i.e., As₂Te₃and As₂Se₃) as dual‐role materials, serving as both dopants and back‐contact materials for high‐efficiency CdSeTe devices, are investigated. During the formation of the back contact, a portion of the arsenic chalcogenides diffuses into the CdSeTe absorber, facilitating p‐type doping. The remaining materials forms a stable back‐contact layer that facilitate carrier collection and reducing recombination losses at the CdSeTe back surface. Particularly, CdSeTe device employing Te rich As₂Te₃layer as the dopant and back‐contact materials achieves a PCE of 18.34%, demonstrating the dual functionality of solution‐processed arsenic chalcogenides in simultaneously doping the absorber and optimizing charge extraction. This solution based cost‐effective As doping approach offers a promising pathway for advancing CdSeTe photovoltaic technology. 

This study compares Spiro-OMeTAD, CuSCN, and PTAA as hole transport layers in carbon-based perovskite solar cells. Spiro-OMeTAD showed best efficiency, CuSCN better stability, while PTAA underperformed, highlighting a performance-stability trade-off. 

To scale out the massive metadata access, the Ceph distributed file system (CephFS) adopts adynamic subtree partitioningmethod, splitting the hierarchical namespace and distributingsubtreesacross multiple metadata servers. However, this method suffers from a severe imbalance problem that may result in poor performance due to its inaccurate imbalance prediction, ignorance of workload characteristics, and unnecessary/invalid migration activities. To eliminate these inefficiencies, we propose Lunule, a novel CephFS metadata load balancer, which employs animbalance factor modelfor accurately determiningwhento trigger re-balance and tolerate unharmful imbalanced situations. Lunule further adopts aworkload-aware migration plannerto appropriately select subtree migration candidates. Finally, we extend Lunule to Lunule⁺, which models metadata accesses into matrices, and employs matrix-based formulas for more accurate load prediction and re-balance decision. Compared to baselines, Lunule achieves better load balance, increases the metadata throughput by up to 315.8%, and shortens the tail job completion time by up to 64.6% for five real-world workloads and their mixture, respectively. Besides, Lunule is capable of handling the metadata cluster expansion and the workload growth, and scales linearly on a 16-node cluster. Compared to Lunule, Lunule⁺achieves up to 64.96% better metadata load balance, and 13.53-86.09% higher throughput. 

Antimony selenide (Sb2Se3) is a promising material for solar energy conversion due to its low toxicity, high stability, and excellent light absorption capabilities. However, Sb2Se3 films produced via physical vapor deposition often exhibit Se-deficient surfaces, which result in a high carrier recombination and poor device performance. The conventional selenization process was used to address selenium loss in Sb2Se3 solar cells with a substrate configuration. However, this traditional selenization method is not suitable for superstrated Sb2Se3 devices with the window layer buried underneath the Sb2Se3 light absorber layer, as it can lead to significant diffusion of the window layer material into Sb2Se3 and damage the device. In this work, we have demonstrated a rapid thermal selenization (RTS) technique that can effectively selenize the Sb2Se3 absorber layer while preventing the S diffusion from the buried CdS window layer into the Sb2Se3 absorber layer. The RTS technique significantly reduces carrier recombination loss and carrier transport resistance and can achieve the highest efficiency of 8.25%. Overall, the RTS method presents a promising approach for enhancing low-dimensional chalcogenide thin films for emerging superstrate chalcogenide solar cell applications. 

Abstract Cadmium telluride (CdTe) thin film solar cells have gained significant attention in the photovoltaic industry due to their high efficiency and low cost. CdTe solar cells have achieved a high‐power conversion efficiency of 23.1%. To further boost the device's performance, it is crucial to systematically tune the doping concentration and carrier concentration, which are dominated by the doping approach and the following dopant activation processes. Both Group I elements (e.g., Cu) and Group V elements (e.g., As) doping have demonstrated high efficiency and utilizing various doping techniques. This review provides an overview of the history of the CdTe thin film technology, doping mechanisms, doping techniques, challenges, and potential solutions to further improve device performance.