Interfacial engineering for organic and perovskite solar cells using molecular materials

Abstract

Organic and perovskite solar cells have recently emerged as promising candidates for next-generation solar energy technologies due to their low-cost solution-based fabrication over large areas even on flexible substrates, while offering the possibility of on-chip integration and patterning for custom-designed applications. A key concern over these emerging technologies is their poor operational stability. In a typical device architecture, the organic or perovskite absorber is usually inserted between an electron and a hole transport (extraction) layer in order to match the energetic differences present at the heterointerfaces with the respective contacts. As these layers considerably influence the device performance and operational stability, they have witnessed intense research efforts in recent years resulting in the development of novel materials. Conductive or insulating polymers, non-polymer molecular materials and transition metal oxides are among the most studied classes of interfacial materials. In this review article, we focus on the application of molecular materials, but excluding polymers, either organic or inorganic, to engineer the interfaces in these devices due to their ease of synthesis and facile functionalization of their structure to meet the requirements for successful device modification. We also include ionic compounds of well-defined stoichiometry such as CuSCN, ionic liquids and compounds of molecular anions as the polyoxometalates. We provide a comprehensive account of various molecular interlayers for organic and perovskite solar cell devices. We highlight the origin of enhanced performance and device lifetime and provide a detailed outlook for a focused future development of these materials.

Downconversion Materials for Perovskite Solar Cells

“…[ 176–178 ] The properties can be altered by doing small changes to the molecular structure by varying the shape and size of molecules, and these molecules being solution processable and having low‐cost deposition. [ 179 ] There are several organic molecules that have been reported previously as ETL and HTL in PSCs. [ 180–182 ] Recently, Bella et al [ 183 ] coated photopolymer on the front side of the device, as a UV‐curable fluoropolymer layer.…”