Highly efficient and thermal stable guanidinium-based two-dimensional perovskite solar cells via partial substitution with hydrophobic ammonium

• 来源期刊: 中国科学:化学（英文版）
• 年，卷（期）: 2019,（7）
• 页码范围: 859-865
• 页数: 7页
• 语种: 英文

摘要

Layered two-dimensional (2D) perovskite solar cells (PVSCs) with a chemical formula of C(NH2)3(CH3NH3)3Pb3I10 (n=3) have been fabricated through additive engineering,wherein stoichiometrically equivalent guanidinium (GA+) and methylammonium (MA+) serve as spacer cations.The crystallinity of the perovskite films is dramatically enhanced with proper amount of methylammonium thiocyanate (MASCN) added into the precursor solution.In addition,we substitute a small amount of MA+ with hydrophobic phenylethylammonium (PEA+),which can passivate trap states of the perovskite films.As a result,the open circuit voltage increases to 1.1 V and the best power conversion efficiency (PCE) of 10.12％ is yielded.Furthermore,superior thermal stability and balanced moisture stability of the PEA-substituted GA-based PVSCs are demonstrated,compared to the popular 3D MAPbI3 and 2D PEA-based PVSCs.They retain approximately 80％ of the original PCE after 30 d at 20％ relative humidity (RH),and 50％ of the original PCE after 3200 min at 85 ℃ without any encapsulation.This work suggests a new route to achieve both heat and humidity stable PVSCs by simply mixing different spacer cations.