Manipulating the crystallization and interfacial charge behavior with a jellyfish-like molecular template for efficient perovskite solar cells

Abstract

The buried electron-transport layer (ETL)/perovskite interface is crucial for the performance of n-i-p-type perovskite solar cells. However, the presence of nonuniform distributed dangling bonds on the mainstream metal oxide ETL surface leads to nonradiative recombination and affects the homogenization of the perovskite film by triggering disordered nucleation. To address these challenges, we modulated the ETL/perovskite interface by introducing a jellyfish-like molecular template (JLMT), where the jellyfish foot was glycine and the jellyfish head was MoS₂, to simultaneously achieve highly oriented perovskite films and efficient interfacial charge transfer. Glycine was first anchored on the ETL through esterification. Then, sequentially layered MoS₂ was deposited on the surface. The lower reduction potential of glycine with respect to that of MoS₂ drives electron transfer from glycine to MoS₂, leading to surface charge doping and building a favorable bandgap alignment at the ETL/perovskite interface. In addition, the top surface of MoS₂, which is free from dangling bonds, could guide the orientational growth of the perovskite because of its lattice structural compatibility. An as-fabricated JLMT device achieved a champion power conversion efficiency (PCE) of 21.76% and an open-circuit voltage (V_oc) of 1.20 V. Furthermore, under room temperature conditions with a relative humidity of ∼30%, the PCE of the JLMT device retained 93% of its initial value after 30 days, whereas the control device only retained around 61% of its initial PCE.