Utomo, D.S.; Svirskaite, L.M.; Prasetio, A.; Malinauskiene, V.; Dally, P.; Aydin, E.; Musiienko, A.; Getautis, V.; Malinauskas, T.; Azmi, R.; De Wolf, S.: Nonfullerene Self-Assembled Monolayers As Electron-Selective Contacts for n-i-p Perovskite Solar Cells. ACS Energy Letters 9 (2024), p. 1682-1692
10.1021/acsenergylett.4c00306
Open Access Version
Abstract:
Organic, nonfullerene semiconductors capable of self-assembly and composed of either anthraquinone (AQ) or naphthalenediimide (NDI) central fragments have been designed as electron-selective materials for n-i-p perovskite solar cells (PSCs). Both types of self-assembled monolayer (SAM) molecules contain phosphonic acid as an anchoring group, allowing covalent binding with indium tin oxide (ITO) surfaces. In particular, the NDI-based SAMs showed a more homogeneous anchoring on the ITO substrate and a stronger band bending at the ITO-SAM/perovskite interface than AQ-based SAMs. As a result, low-temperature-processed n-i-p PSCs with NDI SAMs as an electron-selective bottom contact showed a maximum power conversion efficiency (PCE) of 21.5%, representing the highest PCE among n-i-p PSCs with organic electron transporting layers (ETLs). In addition, our NDI-SAM-based devices demonstrate substantially improved long-term stability under operating temperature conditions when compared to devices using SnO2 as the ETL.