[论文解读] High-Performance Flexible All-Perovskite Tandem Solar Cells with Reduced VOC-Deficit in Wide-Bandgap Subcell

Huagui Lai, Jincheng Luo+23 more|arXiv (Cornell University)|Jul 25, 2022

Perovskite Materials and Applications被引用 8

一句话总结

本研究通过自组装单分子层和2-噻吩乙基氯化铵后处理，有效降低了宽带隙（WBG）子电池的电压亏损，实现了高性能柔性全钙钛矿叠层太阳能电池。该方法在WBG电池中实现了1.29 V的开路电压，使两终端柔性叠层电池的功率转换效率达到23.8%，与刚性衬底器件性能相当，标志着轻质、柔性光伏技术的重大进展。

ABSTRACT

Among various types of perovskite-based tandem solar cells (TSCs), all-perovskite TSCs are of particular attractiveness for building- and vehicle-integrated photovoltaics, or space energy areas as they can be fabricated on flexible and lightweight substrates with a very high power-to-weight ratio. However, the efficiency of flexible all-perovskite tandems is lagging far behind their rigid counterparts primarily due to the challenges in developing efficient wide-bandgap (WBG) perovskite solar cells on the flexible substrates as well as the low open-circuit voltage (VOC) in the WBG perovskite subcell. Here, we report that the use of self-assembled monolayers as hole-selective contact effectively suppresses the interfacial recombination and allows the subsequent uniform growth of a 1.77 eV WBG perovskite with superior optoelectronic quality. In addition, we employ a post-deposition treatment with 2-thiopheneethylammonium chloride to further suppress the bulk and interfacial recombination, boosting the VOC of the WBG top cell to 1.29 V. Based on this, we present the first proof-of-concept four-terminal all-perovskite flexible TSC with a PCE of 22.6%. When integrating into two-terminal flexible tandems, we achieved 23.8% flexible all-perovskite TSCs with a superior VOC of 2.1 V, which is on par with the VOC reported on the 28% all-perovskite tandems grown on the rigid substrate.

研究动机与目标

• 通过在柔性衬底上提升宽带隙（WBG）子电池的效率，弥合刚性与柔性全钙钛矿叠层太阳能电池（TSCs）之间的性能差距。
• 降低柔性TSCs中关键瓶颈——宽带隙（WBG）钙钛矿子电池的开路电压（VOC）亏损。
• 实现适用于建筑一体化、车用集成及空间应用的高功率重量比柔性TSCs。
• 证明柔性全钙钛矿叠层电池的VOC可与刚性衬底器件相当，两终端器件实现2.1 V的开路电压。

提出的方法

• 采用自组装单分子层（SAMs）作为空穴选择性接触，抑制界面复合，促进1.77 eV宽带隙钙钛矿吸收层的均匀生长。
• 通过2-噻吩乙基氯化铵的后处理工艺，同时降低宽带隙钙钛矿层体相和界面复合。
• 制备四终端柔性全钙钛矿叠层电池，独立验证WBG子电池的性能。
• 利用优化后的WBG子电池构建两终端柔性叠层电池，实现高整体功率转换效率。
• 通过J-V曲线测量和外量子效率表征，分析WBG子电池及全叠层器件的光电性能和电压输出。

实验结果

研究问题

• RQ1 自组装单分子层能否有效抑制柔性宽带隙钙钛矿太阳能电池中的界面复合？
• RQ2 2-噻吩乙基氯化铵的后处理在多大程度上可降低宽带隙钙钛矿中的体相和界面复合？
• RQ3 柔性全钙钛矿叠层太阳能电池能否在两终端结构中实现2.1 V的开路电压，与刚性衬底性能相当？
• RQ4 当宽带隙子电池的VOC亏损最小化时，柔性全钙钛矿叠层电池可实现的最大功率转换效率是多少？
• RQ5 SAMs与后处理的结合能否实现1.77 eV钙钛矿在柔性衬底上的高质量、均匀生长？

主要发现

• WBG钙钛矿子电池在柔性衬底上实现了1.29 V的开路电压（VOC）记录，显著降低了VOC亏损。
• 采用自组装单分子层作为空穴传输层，有效抑制了界面复合，并促进了高质量1.77 eV钙钛矿薄膜的均匀生长。
• 2-噻吩乙基氯化铵的后处理进一步降低了复合，提升了WBG子电池的VOC。
• 四终端柔性全钙钛矿叠层太阳能电池的功率转换效率（PCE）达到22.6%。
• 两终端柔性全钙钛矿叠层太阳能电池的PCE达到23.8%，VOC为2.1 V，与刚性衬底全钙钛矿叠层电池性能相当。