物理化学学报

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溶剂工程调控钙钛矿薄膜中PbI2和PbI2(DMSO)的形成

查吴送1,2, 张连萍2, 文龙3, 康嘉晨2, 骆群2,4, 陈沁3, 杨上峰5, 马昌期2,4   

  1. 1 中国科学技术大学纳米学院,江苏 苏州 215123;
    2 中国科学院纳米技术与纳米仿生研究所,印刷电子学部,江苏 苏州 215123;
    3 暨南大学纳米光子学研究院,广州 511443;
    4 中国科学院纳米技术与纳米仿生研究所南昌研究院,南昌 330200;
    5 中国科学技术大学材料科学与工程系,量子信息与量子物理协同创新中心,合肥 230026;
  • 收稿日期:2020-03-09 修回日期:2020-04-05 发布日期:2020-04-15
  • 通讯作者: 骆群, 马昌期 E-mail:qluo2011@sinano.ac.cn;cqma2011@sinano.ac.cn
  • 基金资助:
    江苏省自然科学基金(BK20181197), 江西省自然科学基金(20181BAB206017), 中国科学院青年创新促进会(2019317)和国家自然科学基金(51773224)资助项目

Controllable Formation of PbI2 and PbI2(DMSO) Nano Domains in Perovskite Films through Precursor Solvent Engineering

Wusong Zha1,2, Lianping Zhang2, Long Wen3, Jiachen Kang2, Qun Luo2,4, Qin Chen3, Shangfeng Yang5, Chang-Qi Ma2,4   

  1. 1 Nano Science and Technology Institute, University of Science and Technology of China, Suzhou 215123, Jiangsu Province, P. R. China;
    2 Printable Electronics Research Center, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, Jiangsu Province, P. R. China;
    3 Institute of Nanophotonic, Jinan University, Guangzhou 511443, P. R. China;
    4 Suzhou Institute of Nano-Tech and Nano-Bionics Nanchang, Chinese Academy of Sciences, Nanchang 330200, P. R. China;
    5 Department of Materials Science and Engineering, Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei 230026, P. R. China
  • Received:2020-03-09 Revised:2020-04-05 Published:2020-04-15
  • Supported by:
    The project was supported by the Natural Science Foundation of Jiangsu Province, China (BK20181197), the Natural Science Foundation of Jiangxi Province, China (20181BAB206017), the Youth Innovation Promotion Association, CAS (2019317), and the National Natural Science Foundation of China (51773224).

摘要: 钙钛矿太阳能电池以其高效、低成本的特点备受关注。到目前为止,钙钛矿太阳能电池的最高光电转换效率已经超过25%,显示出良好的应用前景。钙钛矿薄膜的结晶性能是决定器件性能的关键,因此,调控钙钛矿薄膜的生长过程至关重要。本工作中,我们发现通过简单调节前驱体溶剂,即调节二甲基亚砜:1,4-丁内酯:N,N-二甲基甲酰胺(DMSO : GBL : DMF)的三种混合溶剂的比例,可实现钙钛矿薄膜中PbI2和PbI2(DMSO)含量的调节,从而调节电池的器件性能。此外,本工作系统研究了PbI2和PbI2(DMSO)的含量对器件性能的影响。结果表明,PbI2(DMSO)的形成会导致300–425 nm波长范围内电池的外量子效率(EQE)降低,从而导致器件性能下降。相反,通过在前驱体溶液中添加额外的碘化亚甲基铵(MAI),可以抑制PbI2和PbI2(DMSO)的形成。

关键词: 钙钛矿太阳能电池, PbI2, PbI2(DMSO), 钙钛矿前驱体, 外量子效率

Abstract: Perovskite solar cells (PSCs) attract much attention for their high efficiency and low processing cost. Power conversion efficiencies (PCEs) higher than 25% have been reported in literature, demonstrating the excellent application prospect of PSCs. In general, the crystallinity and the film composition of perovskite thin films are significant factors in determining device performance. Much effort has been made to control the growth process of perovskite films through the use of additives, passivation layers, special atmosphere treatments, precursor regulation etc. Among these methods, precursor solvent engineering is a simple and direct way to control the perovskite quality, but the controllability of components through solvent engineering is still difficult and has not yet been reported. Herein, we report the controlled formation of PbI2 and PbI2 with dimethyl sulfoxide (DMSO) nano domains through precursor solvent engineering. In particular, tuning the solvent content of the dimethyl sulfoxide:1,4-butyrolactone:N,N-dimethylformamide (DMSO:GBL:DMF) in the perovskite precursor solution, controlled the content of PbI2 and PbI2(DMSO) domains. Due to the lower boiling point and weaker coordination of DMF relative to DMSO, part of methylammonium iodide (MAI) would escape from the wet films during the evaporation process. Therefore, the PbI2(DMSO) can't completely convert to perovskite crystals and is retained in the final films as residual PbI2(DMSO) domains. Both UV-vis absorption spectrum and XRD spectrum confirmed the existence of PbI2 and PbI2(DMSO) domains. Importantly, the content of PbI2(DMSO) was controllable by simply changing the relative proportion of DMF. With an increase in the DMF content, the residual PbI2(DMSO) domains gradually increase. In addition, the influence of PbI2 and PbI2(DMSO) domains on the device performance was systematically investigated. The formation of PbI2(DMSO) domains caused a decrease in external quantum efficiency (EQE) of the device over 300-425 nm, and consequently decreased the device performance. That was because the PbI2(DMSO) domain has strong absorption over 300-425 nm. Therefore, the PbI2(DMSO) domains would absorb the photons over 300-425 nm prior to the perovskite, however the photons absorbed by the PbI2(DMSO) domains are not converted into the photocurrent. Thus, the perovskite solar cell containing PbI2(DMSO) showed an EQE loss over 300-425 nm in the EQE spectra. This work provides a simple method to control the components, especially the content of the PbI2(DMSO) domains, in perovskite films through regulating the precursor solvent. Additionally, this work revealed a PbI2(DMSO) domain related EQE loss phenomenon, highlighting the importance of controlling this component.

Key words: Perovskite solar cell, PbI2, PbI2(DMSO), Perovskite precursor, External quantum efficiency

MSC2000: 

  • O649