您现在的位置: 首 页 > 新闻通知 > 通知公告

关于举行佐治亚理工学院 Zhiqun Lin教授学术报告的通知

时间:2017-07-17 11:59      发布人:何秋云      阅读:103

报告题目:Engineering Light Absorption and Controlling Crystal Morphology for High-Efficiency Perovskite Solar Cells

报 告 人:Prof. Zhiqun Lin(School of Materials Science and Engineering, Georgia Institute of Technology)

邀 请 人:黄飞 教授
报告时间:7月20日上午10:00
报告地点:发光材料与器件国家重点实验室502会议室

 

Abstract

 

Advances of metal halide perovskites in solar cells have been widely recognized. The power conversion efficiency (PCE) of perovskite solar cells has leaped from approximately 3 % to over 22 %. The photovoltaic performance of perovskite solar cells is highly correlated with chemical composition and film crystallization of perovskite photoactive layer. The chemical composition determines the spectral absorption range and the film crystallization influences the charge recombination. In this context, extending the spectral absorption of metal halide perovskite solar cells from visible into near-infrared (NIR) range renders the minimization of non-absorption loss of solar photons. Moreover, controlling the crystallization of perovskite films enables the reduction of the trap-assisted non-radiative charge recombination. Herein, we report two strategies for improving the photovoltaic performance of perovskite solar cells through engineering light absorption and film crystallization: (1) Monodisperse NaYF4:Yb/Er upconversion nanoparticles (UCNPs) were empolyed as the mesoporous electrode, enabling perovskite solar cells to operate under extended light absorption to NIR range. Uniform NaYF4:Yb/Er UCNPs permanently tethered with hydrophilic polymer as surface ligands were rationally crafted by capitalizing on double hydrophilic star-like poly(acrylic acid)-block-poly(ethylene oxide) (PAA-b-PEO) diblock copolymer as nanoreactor, in which the outer PEO blocks not only imparted the solubility of UCNPs but also rendered the tunability of film porosity during the manufacturing process. The incorporation of NaYF4:Yb/Er UCNPs as the mesoporous electrode led to a high efficiency of 17.8 %, which was further increased to 18.1 % upon the NIR irradiation. (2) Control over the crystallization of metal halide perovskite films is also crucial to pursuing high efficiency. We developed a robust strategy to manufacture large-grained FA0.85MA0.15PbI2.55Br0.45 perovskite film with good crystallization and preferred orientation by meniscus-assisted solution printing (MASP). Central to this strategy is the solvent evaporation-triggered outward convective flow that transported the perovskite solutes to the edge of the meniscus, promoting the formation of micrometer-scale perovskite grains with preferred crystal orientations. The kinetics of grain growth was elucidated by in-situ optical microscopy tracking for further understanding the crystallization mechanism of perovskites during MASP, from which a two-stage, namely, quadratic followed by linear growth of perovskite crystallization was identified. The FA0.85MA0.15PbI2.55Br0.45 perovskite films prepared by the MASP exerted excellent optoelectronic properties such as long carrier lifetimes, low trap-state densities, and eventually high efficiencies approaching 20 % in planar solar cells. As such, these two strategies may open up avenues for the future development of perovskites for optoelectronic applications.

Biography: Dr. Zhiqun Lin is currently Professor of Materials Science and Engineering at the Georgia Institute of Technology. He received the B.S. degree in Materials Chemistry from Xiamen University, Fujian, China in 1995, the Master degree in Macromolecular Science from Fudan University, Shanghai, China in 1998, and the PhD degree in Polymer Science and Engineering from UMass, Amherst in 2002. He did his postdoctoral research at UIUC. He joined the Department of Materials Science and Engineering at the Iowa State University as an Assistant Professor in 2004 and was promoted to Associate Professor in 2010. He moved to Georgia Institute of Technology in 2011, and become a Professor in 2014. His research interests include polymer-based nanocomposites, block copolymers, polymer blends, conjugated polymers, quantum dots (rods, tetrapods and wires), functional nanocrystals (metallic, magnetic, semiconducting, ferroelectric, multiferroic, upconversion and thermoelectric) of different architectures (plain, core/shell, hollow and Janus), solar cells (perovskite solar cells, organic-inorganic hybrid solar cells and dye sensitized solar cells), lithium ion batteries, hydrogen generation, hierarchically structured and assembled materials, and surface and interfacial properties. He has published more than 200 peer reviewed journal articles (with an h-index of 58), 10 book chapters, and 4 books. Currently, he serves as an Associate Editor for Journal of Materials Chemistry A, and an editorial advisory board member for Nanoscale. He is a recipient of Frank J. Padden Jr. Award in Polymer Physics from American Physical Society, an NSF Career Award, a 3 M Non-Tenured Faculty Award, and an invited participant at the National Academy of Engineering’s 2010 US Frontiers of Engineering Symposium. He became a Fellow of Royal Society of Chemistry in 2014 and a Japan Society for Promotion of Science (JSPS) Fellow in 2015. More information on his research can be found at http://nanofm.mse.gatech.edu/.