Flocculating‐Regulated TiO<sub>2</sub> Deposition Enables the Synergistic Effect of Doping for Perovskite Solar Cells with Efficiency Exceeding 25.8%
Huilin Yan, Xing Zhao, Hao Huang, Danxia Wu, Pengkun Zhu, Danni Li, Bingbing Fan, Yujie Qiu, Yuqing Yang, Qi Geng, Peng Cui, Yingying Yang, Zhineng Lan, Meicheng Li
Abstract
Abstract The planar perovskite solar cells (PSCs) using TiO 2 as the electron transport layer (ETL) are undergoing a stagnated efficiency improvement, which the inferior TiO 2 ETL mainly limits. Herein, a flocculating‐regulated TiO 2 deposition using SnCl 2 ·2H 2 O is reported as the flocculate to control the nanoparticle size finely for optimizing TiO 2 deposition and to achieve a synergistic Sn doping. The SnCl 2 ·2H 2 O incorporated into bath precursor can bridge‐link the suspended nanoparticles, which promotes the precipitation of large‐sized nanoparticles and leaves the smaller‐sized nanoparticles for deposition, leading to a compact TiO 2 film with marked reduced surface roughness. Meanwhile, along with flocculating‐regulated TiO 2 deposition, it can also be achieved the Sn‐doping of TiO 2 , which increases the conductivity of TiO 2 thin films by ≈2.5 times. As a consequence, attributing to the optimized interface contact and accelerated interfacial electron transport, the planar PSCs achieved a certification efficiency of 25.85%, the highest value among the TiO 2 ‐based planar PSCs to date. In addition, the PSCs can maintain 99% of their initial efficiency after more than 4500 h of storage in ambient air, showing excellent stability.