In Situ Impurity Phase Repair Strategy Enables Highly‐Efficient Perovskite Solar Cells with Periodic Photovoltaic Performance
The α-FAPbI3 perovskite, ideal for high-efficiency solar cells, suffers from impurity phases causing defects and instability. Using FAI/MASCN vapors repairs impurities into α-FAPbI3, enhancing charge transport and morphology. This achieves 26.05% efficiency, with large-area devices (24.52% for 1 cm2, 22.35% for 17.1 cm2). Cyclic repair retains 94.3% efficiency after two cycles, significantly boosting device durability.
Abstract
The photoactive α-phase of formamidinium lead iodide perovskite (α-FAPbI3) is regarded as one of the ideal materials for high-efficiency perovskite solar cells (PSCs) due to its superior optoelectronic properties. However, during the deposition of α-FAPbI3 perovskite films, the presence of impurity phases, such as PbI2 and δ-FAPbI3, can cause the formation of inherent defects, which leads to suboptimal charge transport and extraction properties, as well as inadequate long-term stability in the film's morphology and structure. To address these issues, an impurity phase repair strategy is employed using FAI/MASCN mixed vapors to convert the impurity phases into light-absorbing α-FAPbI3. Meanwhile, this recrystallization process also facilitates the recovery of its characteristic morphology, thereby improving efficiency and enhancing the durability of PSCs. This approach promotes the PSCs to obtain an efficiency of 26.05% (with a certified efficiency of 25.67%, and steady-state PCE of 25.41%). Additionally, this approach is suitable for the fabrication of large-area devices, obtaining a 1 cm2 device with a PCE of 24.52% and a mini-module (with an area of 17.1 cm2) with a PCE of 22.35%. Furthermore, it is found that this strategy enables cyclic repair of aged perovskite films, with the perovskite solar cells retaining ≈ 94.3% of their initial efficiency after two cycles of repair, significantly enhancing the lifetime of the perovskite solar cells.
Constructing Controlled Vertical Gradient Morphology in Pseudo‐Planar Heterojunction Organic Photovoltaics via Self‐Assembled Interface Orthogonal Strategy
A self-assembled interface orthogonal strategy is first applied to construct pseudo-planar heterojunction organic photovoltaics with controllable vertical gradient distribution morphology. Introducing low surface-energy N2200 to self-assemble molecular layer on PM6 surface overcomes erosion effect and modulates phase morphology, thus achieving the highest efficiency of 19.86% via air-printing process.
Abstract
Precisely regulating vertically distributed morphology by blade-coating process is crucial to realize high-performance large-scale pseudo-planar heterojunction organic photovoltaics (OPVs). However, the thermodynamic motion and random diffusion of donor/acceptor (D/A) generated from the differences in surface energy and concentration during sequentially blade-coating process will cause great challenges for obtaining ideal active layer morphology. Herein, this study have proposed a self-assembled interface orthogonal strategy by introducing low surface energy guest (N2200) to form protective layer on PM6 surface, which counteracts erosion from orthogonal solution of acceptor to enhance continuity of D/A phases, thus promoting directional carrier migration and effectively suppressing energetic disorder. Finally, N2200-modified device achieves the highest power conversion efficiency (PCE) of 19.86%, and large-area module (16.94 cm2) exhibits exceptional PCE (16.43%). This investigation presents innovative insights into morphology issue triggered by molecular motion and provides an effective method for air-printing large-scale OPVs with precisely controlled morphology based on non-halogenated solvent.
Accurate Thermal Resection of Atomically Precise Copper Clusters to Achieve Near‐IR Light‐Driven CO2 Reduction
A novel copper-sulfur-nitrogen cluster Cu8SN is synthesized by using a strong anchoring ability protective ligand (2-mercaptopyrimidine) and a relatively weak monodentate tert-butyl mercaptan ligand. Then, a precise thermal-resection strategy is applied to only peel the targeted weak ligands off, which induces a structural transformation of the initial Cu8SN cluster into a new and more stable Cu–S–N cluster (Cu8SN–T). Cu8SN–T exhibits greatly enhanced light-harvesting abilities and full-spectrum responsive overall CO2 photoreduction with ≈100% CO2-to-CO selectivity.
Abstract
Atomically precise copper clusters are desirable as catalysts for elaborating the structure–activity relationships. The challenge, however, lies in their tendency to sinter when protective ligands are removed, resulting in the destruction of the structural integrity of the model system. Herein, a copper-sulfur-nitrogen cluster [Cu8(StBu)4(PymS)4] (denoted as Cu8SN) is synthesized by using a mixed ligand approach with strong chelating 2-mercaptopyrimidine (PymSH) ligands and relatively weak monodentate tert-butyl mercaptan ligands. A precise thermal-resection strategy is applied to selectively peel only the targeted weak ligands off, which induces a structural transformation of the initial Cu8 cluster into a new and more stable Cu–S–N cluster [Cu8(S)2(PymS)4] (denoted as Cu8SN-T). The residual bridging S2− within the metal core forms asymmetric Cu-S species with a near-infrared (NIR) response, which endows Cu8SN-T with the capability for full-spectrum responsive CO2 photoreduction, achieving a ≈100% CO2-to-CO selectivity. Especially for NIR-driven CO2 reduction, it has a CO evolution of 42.5 µmol g−1 under λ > 780 nm. Importantly, this work represents the first NIR light-responsive copper cluster for efficient CO2 photoreduction and opens an avenue for the precise manipulation of metal cluster structures via a novel thermolysis strategy to develop unprecedented functionalized metal cluster materials.
Thu 15 May 17:00: Completeness Theorems for Variations of Higher-Order Logic
Mike Gordon’s Higher-Order Logic (HOL) is one of the most important logical foundations for interactive theorem proving. The standard semantics of HOL , due to Andrew Pitts, employs a downward closed universe of sets, and interprets HOL ’s Hilbert choice operator via a global choice function on the universe.
In this talk, I introduce a natural Henkin-style notion of general model corresponding to the standard models. By following the Henkin route of proving completeness, I discover an enrichment of HOL deduction that is sound and complete w.r.t. these general models. Variations of my proof also yield completeness results for weaker deduction systems located between standard and (fully) enriched HOL deduction, relative to less constrained models.
=== Hybrid talk ===
Join Zoom Meeting https://cam-ac-uk.zoom.us/j/87143365195?pwd=SELTNkOcfVrIE1IppYCsbooOVqenzI.1
Meeting ID: 871 4336 5195
Passcode: 541180
- Speaker: Andrei Popescu (University of Sheffield)
- Thursday 15 May 2025, 17:00-18:00
- Venue: MR14 Centre for Mathematical Sciences.
- Series: Formalisation of mathematics with interactive theorem provers ; organiser: Anand Rao Tadipatri.
Tue 15 Apr 15:00: In-Context Learning
TBC
- Speaker: Yashar Ahmadian; Nandini Shiralkar
- Tuesday 15 April 2025, 15:00-16:30
- Venue: CBL Seminar Room, Engineering Department, 4th floor Baker building.
- Series: Computational Neuroscience; organiser: .
Mon 12 May 17:00: bla bla
bla bla
- Speaker: Lukas pertl
- Monday 12 May 2025, 17:00-17:45
- Venue: Lecture Theatre 2, Computer Laboratory, William Gates Building.
- Series: Foundation AI; organiser: Pietro Lio.
Tue 03 Jun 16:00: Title to be confirmed
Abstract not available
- Speaker: Rajalakshmi Nandakumar, Cornell University
- Tuesday 03 June 2025, 16:00-17:00
- Venue: Online.
- Series: Mobile and Wearable Health Seminar Series; organiser: Cecilia Mascolo.
Fri 16 May 12:00: Title to be confirmed
Abstract not available
- Speaker: Paul Röttger (Bocconi University)
- Friday 16 May 2025, 12:00-13:00
- Venue: Room FW26 with Hybrid Format. Here is the Zoom link for those that wish to join online: https://cam-ac-uk.zoom.us/j/4751389294?pwd=Z2ZOSDk0eG1wZldVWG1GVVhrTzFIZz09.
- Series: NLIP Seminar Series; organiser: Suchir Salhan.
Thu 01 May 15:00: The Case for Decentralized Scheduling in Modern Datacenters
The growing demand for data centre resources and the slower evolution of their hardware have led to clusters operating at high utilisation. In this talk, I will examine how current schedulers perform under such conditions. I will discuss how centralised schedulers struggle to scale under high load due to the significant network traffic caused by continuously transferring up-to-date node data. Conversely, distributed schedulers scale well but lack a global cluster view, leading to suboptimal task allocations. As a result, existing schedulers impose up to three times longer wait times on tail tasks, which increases job completion times.
I will then introduce our work on decentralised scheduling, focusing on performance, scalability, and load balancing. These schedulers have been largely under-explored due to their design complexity. However, we demonstrate that Murmuration, our job-aware decentralised scheduler, achieves high performance under both normal and high load despite its simple approach using approximate load information. It reduces communication overhead between nodes and schedulers while still achieving balanced cluster load distribution. By the end of this talk, I hope to convince you that decentralised schedulers with approximate knowledge strike the right balance between performance and scalability, making them a practical solution for today’s highly utilised data centres.
Bio: Smita Vijayakumar recently completed her PhD from the Department of Computer Science and Technology at the University of Cambridge, under the supervision of Evangelia Kalyvianaki. As a part of her thesis, she developed a novel decentralised scheduling framework to reduce tail task latencies in highly utilised data centres. She has over twelve years of industry experience working on networking, cloud computing, and distributed systems. She also has an MS from The Ohio State University, where her work investigated cloud resource allocation to bottleneck stages for processing streaming applications. Her research has been published in top-tier conferences, and also as a book. She has also been actively involved in mentoring, teaching, and community leadership, including founding Women Who Go, India.
- Speaker: Smita Vijayakumar, Systems Research Group, Cambridge University Computer Laboratory
- Thursday 01 May 2025, 15:00-16:00
- Venue: Computer Lab, FW11 and Online (MS Teams link below).
- Series: Computer Laboratory Systems Research Group Seminar; organiser: Richard Mortier.
High‐Efficiency Large‐Area Perovskite Solar Cells via a Multifunctional Crystallization Regulating Passivation Additive
A chlorine-substituted aromatic polycyclic compound is introduced into perovskite solar cells to regulate perovskite crystallization, passivate various defects, and enhance hole transport at the HTL/perovskite interface. This approach achieved high efficiencies of 25.04% for 1 cm2 cells and 22.81% for 12 cm2 modules, with excellent stability (maintaining 80% of initial efficiency after 2500 h of MPP tracking under ISOS-L-1 standards).
Abstract
Film morphology and surface/interface defect density play a critical role in determining the efficiency and stability of perovskite solar cells (PSCs). Here, a chlorine-substituted aromatic polycyclic derivative (BNCl) is reported, which shows strong interaction with both lead iodide and dimethyl sulfoxide, to regulate the crystallization of perovskite, along with effective passivation of grain boundaries and surface. In addition, the extruded BNCl molecule at the hole transport layer (HTL)/perovskite interface can facilitate the hole transport, leading to better charge transfer. As a result, certified power conversion efficiencies (PCEs) of 25.04% and 22.81% are achieved for PSCs and minimodules with aperture areas of 1 cm2 and 12 cm2 respectively. In addition, the device maintained 80% of its initial efficiency after 2500 h of maximum power point (MPP) tracking under ISOS-L-1 standard.
Bio-inspired hormonic electrolyte: negative feedback for ultra-stable zinc anodes
DOI: 10.1039/D5EE01058F, CommunicationFan Bu, Shaofei La, Wenbo Zhao, Yifan Deng, Yong Gao, Jizhang Jiang, Qinghe Cao, Jipeng Chen, Pei Song Chee, Salah A. Makhlouf, Cao Guan
Zn-based batteries have been considered as promising alternatives for Li-ion batteries, in terms of high safety, low cost and rich natural resources. Unfortunately, their practical application is greatly limited by...
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Bithiophene Imide-Based Polymer Donor for Alloy-like Ternary Organic Solar Cells with Over 20.5% Efficiency and Enhanced Stability
DOI: 10.1039/D5EE00812C, PaperChangjing Xu, Jie Yang, Sergio Gámez-Valenzuela, Jin-Woo Lee, Jiaxu Che, Peng Chen, Guodong Zhang, Hu Dingqin, Yufei Wang, Jichen Lv, Zhicheng Zhong, Xihan Chen, Guangye Zhang, Fuwen Zhao, Bumjoon Kim, Xugang Guo, Bin Liu
Ternary organic solar cells (TOSCs) based on dual polymer donors offer enhanced absorption and stability by broadening spectral coverage and refining phase morphology. However, the inherent chain entanglement of dual...
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Mon 12 May 19:30: Bioelectronic Medicine
Neurological conditions affect one in six people, imposing significant health, economic and societal burden. Bioelectronic medicine aims to restore or replace neurological function with the help of implantable electronic devices. Unfortunately, significant technological limitations prohibit these devices from reaching patients at scale, as implants are bulky, require invasive implantation procedures, elicit a pronounced foreign body response, and show poor treatment specificity and off-target effects. Over the past decade, novel materials and fabrication methods inspired from the microelectronics industry have been shown to overcome these limitations. Recent literature provides powerful demonstrations of thin film implants that are miniaturised, ultra-conformal, stretchable, multiplexed, integrated with different sensors and actuators, bioresorbable, and minimally invasive. This talk discuss the state-of-the-art of these new technologies and the barriers than need to be overcome to reach patients at scale.
More details here.
- Speaker: Professor George Malliaras FRS, Prince Philip Professor of Technology, Department of Engineering, Cambridge University
- Monday 12 May 2025, 19:30-21:00
- Venue: Location: Wolfson Lecture Theatre, Churchill College, and Zoom.
- Series: Cambridge Society for the Application of Research (CSAR); organiser: John Cook.
Mon 16 Jun 19:30: An Introduction to The Alan Turing Institute, the National Institute for Data Science, and Artificial Intelligence
The Alan Turing Institute was established ten years ago and, in this time, it has delivered a number of worlds firsts such as the first 3D printed stainless steel pedestrian bridge, a digital twin of the United Kingdom’s air space, digital twins of cardiac systems in patients, as well as the research vessel the Sir David Attenborough. This talk will focus on some of the achievements of the institute and describe the Grand Challenges it has defined to address contemporary societal issues we face globally namely in the Environment and Sustainability, Defence and Security, and Health and Medicine.
More details here.
- Speaker: Professor Mark Girolami, Chief Scientist, The Alan Turing Institute; RAE Research Chair in Data Centric Engineering, Cambridge University Engineering Department
- Monday 16 June 2025, 19:30-21:00
- Venue: Location: Wolfson Lecture Theatre, Churchill College, and Zoom.
- Series: Cambridge Society for the Application of Research (CSAR); organiser: John Cook.
Interfacial hydrogen bond modulation of dynamic catalysts for nitrate electroreduction to ammonia
DOI: 10.1039/D5EE00597C, PaperYuchi Wan, Yixiang Tang, Yinze Zuo, Kaian Sun, Zewen Zhuang, Yun Zheng, Wei Yan, Jiujun Zhang, Ruitao Lv
Electrocatalytic nitrate reduction (NO3−RR) shows potentials in clean NH3 synthesis and industrial effluent disposal, turning waste into treasure. However, the catalyst reconstruction mechanism is still ambiguous, and the influence of...
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A Universal Surface Fixed Charge Reconstruction Strategy to Minimize Contact Loss of Wide Bandgap Perovskite Photovoltaics
DOI: 10.1039/D4EE05855K, PaperYaxiong Guo, Fang Yao, Yunchen Zhang, Guoyi Chen, Shengjie Du, Zhixi Yu, Hai Zhou, Weijun Ke, Chun Li, Guojia Fang
It is widely accepted that non-radiative recombination losses in the wide-bandgap (WBG) subcell dominate carrier recombination processes in perovskite tandem photovoltaics. We demonstrate that healing the perovskite top-surface with an...
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Photoelectrochemical comproportionation of pre-treated PET plastics and CO2 to formate
DOI: 10.1039/D5EE00689A, Paper Open Access   This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.Yongpeng Liu, Celine Wing See Yeung, Erwin Reisner
An organic–inorganic photoelectrochemical (PEC) tandem device for converting polyethylene terephthalate (PET) plastics and carbon dioxide (CO2) to formate under simulated solar irradiation.
To cite this article before page numbers are assigned, use the DOI form of citation above.
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Fri 27 Jun 13:00: TBA
Abstract not available
- Speaker: Vicky Metzis
- Friday 27 June 2025, 13:00-14:00
- Venue: Biffen Theater- Please subscribe to mailing list for link.
- Series: Developmental Biology Seminar Series; organiser: Theresa Gross-Thebing.
Fri 20 Jun 13:00: TBA
Abstract not available
- Speaker: Tony Southall
- Friday 20 June 2025, 13:00-14:00
- Venue: Biffen Theater- Please subscribe to mailing list for link.
- Series: Developmental Biology Seminar Series; organiser: Theresa Gross-Thebing.
Fri 23 May 13:00: TBA
Abstract not available
- Speaker: Sarah Bray
- Friday 23 May 2025, 13:00-14:00
- Venue: Biffen Theater- Please subscribe to mailing list for link.
- Series: Developmental Biology Seminar Series; organiser: Theresa Gross-Thebing.