物理化学学报 >> 2021, Vol. 37 >> Issue (4): 2009036.doi: 10.3866/PKU.WHXB202009036

所属专题: 金属卤化物钙钛矿光电材料和器件

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基于易升华添加剂辅助合成纯相富铯CH(NH2)2)xCs1−xPbI3钙钛矿

吕培梁1,2, 高彩芸1,2, 孙秀红2, 孙明亮1,*(), 邵志鹏2,*(), 逄淑平2,*()   

  1. 1 中国海洋大学材料科学与工程学院,山东 青岛 266100
    2 中国科学院青岛生物能源与过程研究所,山东 青岛 266101
  • 收稿日期:2020-09-09 录用日期:2020-10-26 发布日期:2020-11-02
  • 通讯作者: 孙明亮,邵志鹏,逄淑平 E-mail:mlsun@ouc.edu.cn;shaozp@qibebt.ac.cn;pangsp@qibebt.ac.cn
  • 基金资助:
    泰山青年学者(tsqn201812110);国家自然科学基金(51822209);国家自然科学基金(51902324)

Synthesis of Cs-Rich CH(NH2)2)xCs1−xPbI3 Perovskite Films Using Additives with Low Sublimation Temperature

Peiliang Lü1,2, Caiyun Gao1,2, Xiuhong Sun2, Mingliang Sun1,*(), Zhipeng Shao2,*(), Shuping Pang2,*()   

  1. 1 School of Materials Science and Engineering, Ocean University of China, Qingdao 266100, Shandong Province, China
    2 Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, Shandong Province, China
  • Received:2020-09-09 Accepted:2020-10-26 Published:2020-11-02
  • Contact: Mingliang Sun,Zhipeng Shao,Shuping Pang E-mail:mlsun@ouc.edu.cn;shaozp@qibebt.ac.cn;pangsp@qibebt.ac.cn
  • About author:Email: pangsp@qibebt.ac.cn. (S.P.)
    Email: shaozp@qibebt.ac.cn. (Z.P.)
    Email: mlsun@ouc.edu.cn. (M.S.)
  • Supported by:
    the Young Taishan Scholars(tsqn201812110);the National Natural Science Foundation of China(51822209);the National Natural Science Foundation of China(51902324)

摘要:

钙钛矿材料化学组分是决定钙钛矿太阳能电池效率和稳定性的关键,纯无机钙钛矿CsPbI3具有相对较好的热稳定性和光稳定性,但由于Cs+具有较小的离子半径而导致无机钙钛矿相不稳定。最近研究发现富铯FAxCs1−xPbI3钙钛矿具有相对稳定的相结构,且可以很大程度上保持无机钙钛矿材料的热稳定性和光照稳定性,是一种非常具有前景的钙钛矿材料体系。目前这种富铯的FAxCs1−xPbI3材料合成是通过引入过量有机组分FAI实现的,其中FAI一方面充当钙钛矿的掺杂剂,另一方面过量的FAI充当添加剂。由于其具有较高的升华温度,后续需要较高的温度使过量的FAI升华,实际上这在实验上很难实现对FAI升华量的精确控制。本文重点研究具有低升华温度的胺类,如碘甲胺(MAI)、碘化二甲胺(DMAI)、碘化乙胺(EAI)、碘化胺(NH4I)和醋酸甲脒(FAAC),作为添加剂制备富铯FAxCs1−xPbI3钙钛矿材料体系的可行性,这一方面可以有效降低钙钛矿薄膜的热处理温度;另一方面可拓宽的制备纯相钙钛矿成分的窗口期,这对大面积制备纯相富铯FAxCs1−xPbI3钙钛矿薄膜尤为重要。结果表明MAI和DMAI可以作为合成FAxCs1−xPbI3钙钛矿材料的有效添加剂,其与PbI2间较强的作用力可以促进Cs4PbI6的形成并有效抑制δ-CsPbI3副产物的生成。合适的升华温度可以使薄膜在保持钙钛矿相结构的同时在较低温度升华去除过量的添加剂,最终实现在相对温和的条件下制备纯相富铯FAxCs1−xPbI3钙钛矿材料。

关键词: 无机卤化物钙钛矿, 甲脒, 掺杂, 添加剂, 太阳能电池

Abstract:

Chemical components of perovskite layers play a key role in improving the efficiency and stability of perovskite solar cells. Pure inorganic perovskites exhibit good thermal and light stabilities; however, the smaller radius of Cs+ leads to a poor perovskite phase stability. In this case, the Cs-rich (CH(NH2)2)xCs1−xPbI3 ((CH(NH2)2+=FA+) perovskite seems more promising because it simultaneously offers the above-mentioned properties, while not forming an unstable perovskite phase. Thus far, the synthesis of Cs-rich FAxCs1−xPbI3 perovskite has been realized by introducing excess formamidinium iodide (FAI) as an additive. However, FAI sublimates at a high temperature and excessive FAI sublimation necessitates even greater temperatures. Therefore, it is difficult to precisely control the ratio of the sublimated FAI from the perovskite film. Herein, the precise synthesis of Cs-rich FAxCs1−xPbI3 perovskites at relatively low sublimation temperatures using amine additives, such as methylammonium iodide (MAI), dimethylamine iodide (DMAI), ethylamine iodide (EAI), ammonium iodide (NH4I), and formamidine acetate (FAAC), was studied. The reaction temperature was reduced when utilizing these additives. Moreover, the window period for the preparation has been widened, which is particularly important for the preparation of pure phase Cs-rich FAxCs1−xPbI3 perovskite films for large devices. In the experiment, perovskite FA0.15Cs0.85PbI3 was selected because of its good stability. The reaction process of the additive that assisted perovskite preparation was studied. Firstly, 0.85 mmol of MAI, DMAI, EAI, FAAC, and NH4I each were added to 1 mmol of FA0.15Cs0.85PbI3 solution. Then, the precursor solution was spin-coated and thermally annealed. The FA0.15Cs0.85PbI3 films were formed by sublimation of the additives during thermal annealing. The influence of different additives on the film formation process was traced using X-ray diffraction (XRD) measurements and UV-visible absorbance spectra (UV-Vis abs). The results showed that MAI and DMAI could be used as additives in the preparation of FA0.15Cs0.85PbI3 films. The strong intermolecular interaction between these additives and PbI2 could benefit the formation of Cs4PbI6 and prevent the formation of δ-CsPbI3. Cs+ is easier to migrate in Cs4PbI6 than in δ-CsPbI3, which provides a necessary condition for the ion exchange reaction. Simultaneously, the mild sublimation temperature of the additives ensured that the films maintain their perovskite phase. Finally, pure phase Cs-rich FAxCs1−xPbI3 perovskites were prepared using this method at a relatively lower temperature of 200 ℃. The XRD and UV-Vis absorption results confirmed the precise synthesis of FA0.15Cs0.85PbI3. The FA0.15Cs0.85 PbI3 solar cells synthesized with MAI and DMAI achieved the maximum power conversion efficiencies of 15.6% and 15.1%, respectively.

Key words: Inorganic halide perovskite, Formamidine, Doping, Additive, Solar cell

MSC2000: 

  • O646