C60 Thin Films in Perovskite Solar Cells: Efficient or Limiting Charge Transport Layer?

Abstract

In this work, we identify the importance of C60 and compact-TiO2 (cTiO2) as electron transport layers on the device performance of coevaporated n–i–p perovskite solar cells. We found (1) a synergetic effect between both layers when extracting the charges and (2) that optimization of the C60 layer is essential for obtaining devices with enhanced device performance. In particular, we found that a C60 layer of an optimum thickness (20 nm), an additional charge transport resistance is observed by impedance analysis, indicating that devices with nonoptimized C60 thickness could limit the fabrication of highly efficient perovskite solar cells.N.K., C.M., A.O.A., and F.F.-S. thank the European Union′s Horizon 2020 research nos. 764787 and 763977. H.K. acknowledges the support of the H2020 program for Solar-ERANET funding of the BOBTANDEM (2019-2022) A.A.S. and C.I. acknowledge the Swiss National Science Foundation (SNSF) funding through Synergia Grant EPISODE (grant no. CRSII5_171000). The authors thank the project German Research Foundation (DFG) (Projekt number 424101351)–Swiss National Foundation (SNF) (200021E_186390). A.O.A. and F.F.-S. acknowledge Ministerio de Economía y Competitividad (MINECO) from Spain under the project ENE2017-85087-C3-1-R and Generalitat Valenciana under the project PROMETEO/2020/028 for financial support