Enhancing the efficiency and stability of p-i-n triple cation perovskite solar cells using benzyl cyanoacetate passivation agent

Abstract

It is extremely difficult to realize high-performance perovskite solar cells (PeSCs) due to a large number of defects of perovskite. Thus, perovskite defects should be passivated as much as possible. In this study, effective cyano (CN), benzene ring, and carbonyl (CO) functional groups were newly introduced to benzyl cyanoacetate (BCA) to prepare a multifunctional BCA passivation agent. The influence of functional group of BCA passivation molecule on perovskite and PeSCs was systemically studied using cyanoethyl acrylate (CA) with CN without benzene ring and benzyl acrylate (BA) with benzene ring without CN as reference molecules. Through various analyses, we found that the novel BCA passivation agent with both CN and benzene ring passivated perovskite defects the most efficiently. Thus, the combination of each effective functional group can synergistically passivate more perovskite defects. As a result, PeSCs created using BCA showed improved power conversion efficiency (PCE) from 18.38 % to 20.23 %. Additionally, PeSC with BCA retained 70 % of the initial PCE after ∼2034 h of air exposure test, 80 % of the initial PCE after ∼193 h of heat aging test, and 60 % of the initial PCE after ∼72 h of light-soaking test, demonstrating better stability than PeSC without BCA in air/heat/light-soaking stability.