Browsing by Author "Li, G."
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Item Managing Excess Lead Iodide with Functionalized Oxo-Graphene Nanosheets for Stable Perovskite Solar Cells(Angewandte Chemie International Edition, 2023) Li, G.; Li, M.; Agyei-Tuffour, B.; et al.Stability issues could prevent lead halide perovskite solar cells (PSCs) from commercialization despite it having a comparable power conversion efficiency (PCE) to silicon solar cells. Overcoming drawbacks affecting their long-term stability is gaining incremental importance. Excess lead iodide (PbI2) causes perovskite degradation, although it aids in crystal growth and defect passivation. Herein, we synthesized functionalized oxo-graphene nanosheets (Dec-oxoG NSs) to effectively manage the excess PbI2. Dec-oxoG NSs provide anchoring sites to bind the excess PbI2 and passivate perovskite grain boundaries, thereby reducing charge recombination loss and significantly boosting the extraction of free electrons. The inclusion of Dec-oxoG NSs leads to a PCE of 23.7% in inverted (p-i-n) PSCs. The devices retain 93.8% of their initial efficiency after 1,000 hours of tracking at maximum power points under continuous one-sun illumination and exhibit high stability under thermal and ambient conditions. [*] Dr. G. Li,+ Prof. Dr. M. Li, Y. Tang, Z. Zhang Key Lab for Special Functional Materials of Ministry of Education, National & Local Joint Engineering Research Center for High efficiency Display and Lighting Technology, School of Materials Science and Engineering, Collaborative Innovation Center of Nano Functional Materials and Applications, Henan University Kaifeng 475004 (China) E-mail: mengli@henu.edu.cn Dr. G. Li,+ Prof. Dr. M. Li, Dr. A. Musiienko, F. Akhundova, J. Li, K. Prashanthan, Dr. F. Yang, S. Trofimov, S. Zuo, L. Wu, L. Wang, Dr. Y. Yang, Dr. B. Agyei-Tuffour, Dr. R. W. MacQueen, Dr. B. Naydenov, Dr. T. Unold, Prof. Dr. E. Unger, Prof. Dr. A. Abate Helmholtz-Zentrum Berlin für Materialien und Energie GmbH Hahn-Meitner-Platz 1, 14109 Berlin (Germany) E-mail: antonio.abate@helmholtz-berlin.de Dr. G. Li,+ Prof. Dr. A. Abate Department of Chemistry, Bielefeld University Universitätsstraße 25, 33615 Bielefeld (Germany) Dr. G. Li+ Present address: Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne (Switzerland) Dr. Y. Hu,+ Q. Cao, Prof. Dr. S. Eigler Institute of Chemistry and Biochemistry, Freie Universität Berlin Altensteinstraße 23a, 14195 Berlin (Germany) E-mail: siegfried.eigler@fu-berlin.de Dr. Y. Hu+ CNRS, Immunology, Immunopathology and Therapeutic Chemistry, UPR3572, University of Strasbourg, ISIS 67000 Strasbourg (France) K. Prashanthan Department of Physics, University of JaffnItem Nanomaterials in 2-dimensions for flexible solar cell applications – a review(Cogent Engineering, 2022) Agyei-Tuffour, B.; Mensah-Darkwa, K.; Ampong, D.N.; Addae, E.A.; Gbadam, G.S.; Darko, C.N.S.; Akyaw, A.O.; Adjah, J.; Asare, J.; Li, G.; Goosen, N.J.This review presents the progress, challenges and prospects of ultrathin flexible photovoltaic devices based on 2-dimensional (2D) nanomaterials. These devices have shown very high performance in bending stabilities for up to ~90% of their power conversion efficiencies (PCEs) after multiple bending deformations. They are thin film PVs with lightweight and mechanically robust structures that allow use in the continual advancing solar cell applications. In this paper, comprehensive assessments of 2D nanomaterials, their syntheses methods, performance, degradation, mechanical and opto-electronic characterization in flexible photovoltaic (PV) cells are highlighted. Semi-conductor materials such as conjugated donor and acceptor polymers, small donor/acceptor molecules and organometal halide perovskites for use as active layers in such flexible solar cell structures are reviewed. The challenges and prospects associated with the adoption of 2D nanomaterials in flexible solar cells are presented. The review highlights the need to transition laboratory results on 2D nanomaterials based flexible solar cells into scale up and commercialized products despite the existing and also opens research areas for researchers to explore and achieve robust and high-efficient solar devicesItem Variation in rice cadmium related to human exposure(Environmental Science and Technology, 2013-05) Meharg, A.A.; Norton, G.; Deacon, C.; Williams, P.; Adomako, E.E.; Price, A.; Zhu, Y.; Li, G.; Zhao, F.J.; McGrath, S.; Villada, A.; Sommella, A.; De Silva, P.M.C.S.; Brammer, H.; Dasgupta, T.; Islam, M.R.Cereal grains are the dominant source of cadmium in the human diet, with rice being to the fore. Here we explore the effect of geographic, genetic, and processing (milling) factors on rice grain cadmium and rice consumption rates that lead to dietary variance in cadmium intake. From a survey of 12 countries on four continents, cadmium levels in rice grain were the highest in Bangladesh and Sri Lanka, with both these countries also having high per capita rice intakes. For Bangladesh and Sri Lanka, there was high weekly intake of cadmium from rice, leading to intakes deemed unsafe by international and national regulators. While genetic variance, and to a lesser extent milling, provide strategies for reducing cadmium in rice, caution has to be used, as there is environmental regulation as well as genetic regulation of cadmium accumulation within rice grains. For countries that import rice, grain cadmium can be controlled by where that rice is sourced, but for countries with subsistence rice economies that have high levels of cadmium in rice grain, agronomic and breeding strategies are required to lower grain cadmium. © 2013 American Chemical Society.