聚乙烯吡咯烷酮链段长度依赖的钙钛矿结晶动力学和电致发光研究  

Polyvinyl Pyrrolidone Segment Length Dependent Perovskite Crystallization Kinetics and Electroluminescence Performance

作　　者：陈文轩 何敏 陈平 陈琪[1,3] CHEN Wenxuan;HE Min;CHEN Ping;CHEN Qi(School of Nano-Tech and Nano-Bionics,University of Science and Technology of China,Hefei 230026,China;Nano Science and Technology Institute,University of Science and Technology of China,Suzhou 215123,China;CAS Key Laboratory of Nanophotonic Materials and Devices,i-Lab,Suzhou Institute of Nano-Tech and Nano-Bionics,Suzhou 215123,China;Chongqing key Laboratory of Micro&Nano Structure Optoelectronics,School of Physical Science and Technology,Southwest University,Chongqing 400715,China)

机构地区：[1]中国科学技术大学纳米技术与纳米仿生学院,合肥230026 [2]中国科学技术大学纳米科学技术学院,苏州215123 [3]中国科学院苏州纳米技术与纳米仿生研究所创新实验室中科院纳米光子材料与器件重点实验室,苏州215123 [4]西南大学物理科学与技术学院微纳结构光电子学重庆市重点实验室,重庆400715

出　　处：《光子学报》2023年第8期206-213,共8页Acta Photonica Sinica

基　　金：科技部国家重点研发计划(No.2021YFA1202802);国家自然科学基金(Nos.21875280,21991150,21991153,22022205);中国科学院稳定支持基础研究领域青年团队计划(No.YSBR-054);江苏省碳达峰碳中和科技创新专项资金项目(No.BE2022026);重庆市自然科学基金(No.CSTB2022NSCQ-MSX0438)。

摘　　要：基于低温溶液工艺的钙钛矿发光二极管由于低成本,高色纯度,宽色域等优势受到广泛关注。然而,在溶液结晶成膜过程中,钙钛矿晶粒无规形核、快速生长,导致薄膜存在大量的针孔和缺陷,严重影响器件性能。本文通过原位荧光和结构表征技术证实,聚乙烯吡咯烷酮(PVP)添加剂在特定的链段长度下,能优化调控钙钛矿结晶动力学,延缓晶粒生长速度,使得钙钛矿薄膜粗糙度由1.489 nm降低到0.954 nm,缺陷密度从1.55×10^(18)cm^(-3)降低至1.05×10^(18)cm^(-3)。相应地,薄膜荧光量子产率从16.9%提升到58.9%,器件外量子效率从8.55%提高到了18.00%。本文通过原位表征技术,全方位解析了添加剂分子结构对钙钛矿结晶动力学的调控机理,为添加剂分子的优化设计提供了直观依据。Solution-processed Perovskite Light-Emitting Diodes (PeLEDs) has drawn much attention due to their low cost,narrow emission spectra and wide color gamut.However,undesirable pinholes and defects of perovskite films impair device performance,which is attributed to the atactic nucleation and rapid crystallization during solution processing.In general,the antisolvent is added to the perovskite spin coating process to quickly remove excess solvent and form an intermediate phase.Combining with annealing treatment,mesophase gradually transforms into the perovskite phase and dense perovskite film can be obtained.At the same time,the larger organic cation (PEA+,TEA+,etc.) will cut continuous lead halide octahedron into the periodic quantum well structure to form quasi-two-dimensional perovskite which has a larger exciton binding energy and rapid energy transfer.By adding the large polymers to the precursor,long segments cannot enter the perovskite lattice and act as the“framework”in the perovskite crystallization process,which can restrict nucleation sites,inhibit the rapid growth of grains and further optimize the film quality.However,the size,fluidity and solubility of the polymer change with the increase of the segment length,which significantly affects the growth of perovskite crystals.Therefore,it is crucial to systematically study the regulation law of polymer segment length on the crystallization kinetics of perovskite to improve the quality of perovskite thin films and thus promote the electroluminescence properties.Polyvinyl Pyrrolidone (PVP),a common non-ionic polymer,its structure is relatively simple and carbon segment length can be accurately controlled by molecular weight.Moreover,PVP contains a carbonyl group,which can effectively passivate the defects in perovskite.In this work,perovskite crystallization kinetics has been tuned by the incorporation of Polyvinyl Pyrrolidone (PVP) with different segment length.Based on in-situ photoluminescence and X-Ray Diffraction (XRD) spectra,it showed that perovskit

关 键 词：钙钛矿发光二极管 结晶动力学 聚合物添加剂 链段长度 原位表征 

分 类 号：TN312.8[电子电信—物理电子学]