One-Dimensional Self-Standing TiO 2 Nanotube Array Layers Designed for Perovskite Solar Cell Applications

The ETL and its interfacewith the organometallic trihalide are key to obtaining efficientand stable cells. The ETL not only receives and transports theelectronic charges but also influences the sensitization throughvariousaspects:the perovskite layer morphologyand loading,which depend on the structure and roughnessofthe ETL, thequality of the ETL–perovskite interface and the quality of theperovskite itself, as the ETL intervenes in the full precursor con-version into perovskite.