Zhao Wenhao, Guo Pengfei, Wu Jiahao, Lin Deyou, Jia Ning, Fang Zhiyu, Liu Chong, Ye Qian, Zou Jijun, Zhou Yuanyuan, Wang Hongqiang
State Key Laboratory of Solidification Processing, Center for Nano Energy Materials, School of Materials Science and Engineering, Northwestern Polytechnical University and Shaanxi Joint Laboratory of Graphene (NPU), Xi'an, 710072, People's Republic of China.
Chongqing Innovation Center of Northwestern, Polytechnical University, Northwestern Polytechnical University, Chongqing, 401135, People's Republic of China.
Nanomicro Lett. 2024 May 3;16(1):191. doi: 10.1007/s40820-024-01407-3.
Low-temperature processed electron transport layer (ETL) of TiO that is widely used in planar perovskite solar cells (PSCs) has inherent low carrier mobility, resulting in insufficient photogenerated electron transport and thus recombination loss at buried interface. Herein, we demonstrate an effective strategy of laser embedding of p-n homojunctions in the TiO ETL to accelerate electron transport in PSCs, through localized build-in electric fields that enables boosted electron mobility by two orders of magnitude. Such embedding is found significantly helpful for not only the enhanced crystallization quality of TiO ETL, but the fabrication of perovskite films with larger-grain and the less-trap-states. The embedded p-n homojunction enables also the modulation of interfacial energy level between perovskite layers and ETLs, favoring for the reduced voltage deficit of PSCs. Benefiting from these merits, the formamidinium lead iodide (FAPbI) PSCs employing such ETLs deliver a champion efficiency of 25.50%, along with much-improved device stability under harsh conditions, i.e., maintain over 95% of their initial efficiency after operation at maximum power point under continuous heat and illumination for 500 h, as well as mixed-cation PSCs with a champion efficiency of 22.02% and over 3000 h of ambient storage under humidity stability of 40%. Present study offers new possibilities of regulating charge transport layers via p-n homojunction embedding for high performance optoelectronics.
广泛应用于平面钙钛矿太阳能电池（PSC）中的低温处理二氧化钛电子传输层（ETL）具有固有的低载流子迁移率，导致光生电子传输不足，从而在掩埋界面处产生复合损失。在此，我们展示了一种在TiO ETL中激光嵌入p-n同质结的有效策略，通过局部内建电场来加速PSC中的电子传输，该电场可使电子迁移率提高两个数量级。发现这种嵌入不仅对提高TiO ETL的结晶质量有显著帮助，而且对制备具有更大晶粒和更少陷阱态的钙钛矿薄膜也有帮助。嵌入的p-n同质结还能够调节钙钛矿层和ETL之间的界面能级，有利于降低PSC的电压损失。受益于这些优点，采用这种ETL的甲脒碘化铅（FAPbI）PSC的最高效率达到25.50%，并且在恶劣条件下具有大大提高的器件稳定性，即在连续加热和光照下最大功率点运行500小时后，仍保持其初始效率的95%以上，以及混合阳离子PSC的最高效率为22.02%，在40%湿度稳定性下可在环境中存储超过3000小时。本研究为通过p-n同质结嵌入调节电荷传输层以实现高性能光电器件提供了新的可能性。
