A facile strategy to adjust SnO2/perovskite interfacial properties for high-efficiency perovskite solar cells†
Abstract
The interface between the electron transport layer (ETL) and the perovskite film plays a vital role in the performance of perovskite solar cells (PSCs). Here, (2-hydroxyethyl)amine hydroiodide (EOAI) is employed to regulate the interface properties at the SnO2/perovskite. The –NH3+ positive and I− negative ion groups in EOAI, which are anchored on the surface of SnO2 through –OH groups, can passivate the interface defects of perovskite films. Besides, the modified ETL has a smaller work function (WF) and EVB than pristine ones, which contributes to efficient charge transport and collection. Furthermore, the introduction of EOAI can also improve the crystallinity of the perovskite layer. As a result, PSCs with EOAI-modified SnO2 produce a champion power conversion efficiency (PCE) of 22.61%, and an improved environmental stability. At the same time, the 1.68 eV wide-band gap perovskite solar cell achieved a PCE close to 20% and the semitransparent device also achieved an efficiency of over 17%.