Inverted perovskite solar cells based on NiO and CoO as hole transport layers

• Grant number: 25/03681-6
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: June 01, 2025
• End date: May 31, 2027
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Carlos Frederico de Oliveira Graeff
• Grantee: Sajid
• Host Institution: Faculdade de Ciências (FC). Universidade Estadual Paulista (UNESP). Campus de Bauru. Bauru , SP, Brazil
• Associated research grant: 20/12356-8 - Stability optimization of perovskite solar cells, AP.TEM

Abstract

Perovskite solar cells (CSPs) based on organic-inorganic hybrids compounds such as CH3NH3PbI3 have become one of the most promising photovoltaic technologies, as they have shown high photoconversion efficiency (PCE), greater than 25%, and low cost. However, its low stability, mainly in the presence of humidity is a barrier to its commercialization. So, the searcher for materials with superior stability is in constant evolution. The focus of this project is the development of inorganic hole transport materials (HTL) replacing organic materials such as poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). Inorganic HTL such as NiO and CoO have high stability, which increases the stability of the devices. PCE of CSPs using NiO as HTL and hybrid organic-inorganic perovskite absorber showed up to 22.1 % of efficiency, and 15% combining NiO and inorganic-based perovskite absorber. In addition, NiO large-scale fabrication process has been demonstrated to be advanced in the last years. These considerations, added to the excellent reported stability, show clearly that NiO is an excellent inorganic hole transport layer for CSPs, which is the focus of this project. Recently, the stability of the NiO/perovskite interface is showed to be problematic. NiO surface react with perovskite film, especially under thermal and electrical stress. So, the interface mechanism degradation process must be understood, and interface engineering strategies must be adopted for long-term stability. In addition to NiO, the introduction of CoO is proposed. CoO is an excellent candidate for HTL in CSPs that was not yet explored, with the potential to minimize the effects of interface degradation.