Improved extraction performance of SnO2 ETL for perovskite solar cells by a combined hydrolysis oxidation and sol-gel method
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摘要: SnO2由于其高电子迁移率、优良的传导性和低温制备特性,在钙钛矿太阳能电池(PSCs)中得到广泛的应用。目前,制备SnO2最常用的两种方法是SnCl2水解氧化法和SnO2溶胶-凝胶法。然而,SnCl2水解氧化虽然可以产生结晶良好的SnO2,但其可控性较差,使得器件性能的重复性较低。另一方面,溶胶-凝胶法制备的基于SnO2电子输运层的器件具有良好的重复性,但结晶度较差,导致电子输运性能下降。在本文中,采用水解氧化和溶胶-凝胶相结合的方法制备了SnO2电子传输层。研究结果表明:采用SnCl2水解氧化法制备高质量的SnO2结晶层可以作为预生长模板,提高溶胶-凝胶法制备SnO2的结晶质量。此外,用溶胶-凝胶法制备的SnO2结晶层覆盖水解氧化SnO2层可以提高器件制备的重复性。由此方法制备的电子传递层可以有效地提高薄膜晶体的生长质量和电荷的提取能力,最终有助于提高器件的效率及稳定性并减少迟滞。
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关键词:
- SnO2 /
- 复合电子传输层 /
- 水解氧化 /
- 溶胶-凝胶法 /
- 杂化钙钛矿太阳能电池
Abstract: SnO2 is widely used in perovskite solar cells (PSCs) due to its high electron mobility, suitable conduction band and low-temperature preparation characteristics. Currently, the two most commonly used methods for preparing SnO2 are SnCl2 hydrolysis oxidation or SnO2 sol-gel preparation. However, although SnCl2 hydrolysis oxidation can produce well-crystallized SnO2, its controllability is poor, resulting in low device performance repeatability. On the other hand, the devices based on SnO2 electronic transport layer prepared by the sol-gel method have good repeatability, but usually have poor crystallinity, leading to a decrease in electron transport performance. In this study, a combination of hydrolysis oxidation and sol-gel methods was used to prepare SnO2 electronic transport layers. The results of the study demonstrate that using SnCl2 hydrolysis oxidation to prepare high-quality SnO2 crystalline layers can serve as a pre-growth template to improve the crystalline quality of sol-gel generated SnO2. Additionally, covering the hydrolysis oxidation-based SnO2 layer with sol-gel prepared SnO2 crystalline layer can improves the repeatability of device preparation. The electron transport layers prepared by this method can effectively enhance the quality of thin film crystal growth and charge extraction capability, ultimately contributing to improving the efficiency, stability, and reducing hysteresis of the devices.-
Key words:
- SnO2 /
- composite electron transport layer /
- hydrolysis oxidation /
- sol-gel method /
- hybrid PSCs
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图 6 (FAPbI3)0.83(MAPbBr3)0.17在ITO/SnCl2/SnO2、ITO/SnCl2和ITO/SnO2 3种衬底上制备的器件:(a) 归一化开电压衰减曲线;(b)基于开电压衰减计算的电子寿命
Figure 6. (FAPbI3)0.83(MAPbBr3)0.17 devices prepared on three ITO/SnCl2/SnO2, ITO/SnCl2, and ITO/SnO2 substrates: (a) Normalized open voltage decay curves; (b) Electron lifetime calculated by open voltage decay
图 7 (a) 3种方法制备的ETL构建的(FAPbI3)0.83(MAPbBr3)0.17太阳能电池的J-V曲线;(b)基于3种方法制备的ETL的20个器件(FAPbI3)0.83(MAPbBr3)0.17器件的效率箱形图
Figure 7. (a) J-V curves of (FAPbI3)0.83(MAPbBr3)0.17 solar cells fabricated with ETLs prepared by using the three methods; (b) Box plot of efficiencies of 20 devices for (FAPbI3)0.83(MAPbBr3)0.17 devices based on different ETLs
表 1 不同衬底(FAPbI3)0.83(MAPbBr3)0.17薄膜的瞬态荧光光谱(TRPL)拟合参数
Table 1. Transient photoluminescence spectroscopy (TRPL) fitting parameters of (FAPbI3)0.83(MAPbBr3)0.17 films prepared on different substrates
Sample τ1,Value/ns τ1,Rel./% τ2,Value/ns τ2,Rel./% τave,Value/ns Glass 5.52 68.48 38.16 31.52 30.36 SnCl2/SnO2 2.09 35.87 20.63 64.13 19.64 SnCl2 4.32 55.79 25.56 44.21 21.83 SnO2 4.04 58.24 29.91 41.76 25.81 Notes: τ1,Value and τ2,Value—Fast decay life and slow decay life; τ1,Rel. and τ2,Rel.—Proportion of fast decay lifespan and the proportion of slow decay lifespan; τave,Value—Fluorescence lifetime of perovskite charge carriers. 表 2 不同制备方法制备的(FAPbI3)0.83(MAPbBr3)0.17器件作为电子传输层的光电参数
Table 2. Optoelectronic parameters of (FAPbI3)0.83(MAPbBr3)0.17 devices prepared using different preparation methods as electron transport layers
ETLs Voc/V Jsc/(mA·cm−2) FF/% PCE/% SnCl2-revese 0.99 21.31 62.90 13.30 SnCl2-forward 0.90 21.25 45.95 8.78 SnO2-reverse 0.89 21.92 63.43 12.38 SnO2-forward 0.87 21.44 59.74 11.16 SnCl2/SnO2-reverse 1.08 20.81 72.56 16.32 SnCl2/SnO2-forward 1.07 20.75 70.51 15.64 Notes: Voc—Open circuit voltage; Jsc—Short-circuit current; FF—Fill factor; PCE—Photoelectric conversion efficiency of perovskite solar cells. -
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