Suppressed Degradation and Enhanced Performance of CsPbI3 Perovskite Quantum Dot Solar Cells via Engineering of Electron Transport Layers

• Published in: ACS applied materials & interfaces Vol. 13; no. 5; pp. 6119 - 6129
• Main Authors: Lim, S, Kim, J, Park, J. Y, Min, J, Yun, S, Park, T, Kim, Y, Choi, J
• Format: Journal Article
• Language: English
• Published: American Chemical Society 10-02-2021
• Subjects: Energy, Environmental, and Catalysis Applications; electron transport layers; colloidal quantum dots; solar cells; CsPbI3 perovskite quantum dots; phase stability
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.0c15484

CsPbI3 perovskite quantum dots (CsPbI3-PQDs) have recently come into focus as a light-harvesting material that can act as a platform through which to combine the material advantages of both perovskites and QDs. However, the low cubic-phase stability of CsPbI3-PQDs in ambient conditions has been recognized as a factor that inhibits device stability. TiO2 nanoparticles are the most regularly used materials as an electron transport layer (ETL) in CsPbI3-PQD photovoltaics; however, we found that TiO2 can facilitate the cubic-phase degradation of CsPbI3-PQDs due to its vigorous photocatalytic activity. To address these issues, we have developed chloride-passivated SnO2 QDs (Cl@SnO2 QDs), which have low photocatalytic activity and few surface traps, to suppress the cubic-phase degradation of CsPbI3-PQDs. Given these advantages, the CsPbI3-PQD solar cells based on Cl@SnO2 ETLs show significantly improved device operational stability (under conditions of 50% relative humidity and 1-sun illumination), compared to those based on TiO2 ETLs. In addition, the Cl@SnO2-based devices showed improved open circuit voltage and photocurrent density, resulting in enhanced power conversion efficiency (PCE) up to 14.5% compared to that of TiO2-based control devices (PCE of 13.8%).