Unveiling the importance of dripping temperature control of hybrid organic-inorganic perovskite precursor solution for the fabrication of fully ambient air-processed perovskite solar cells

Abstract

Given the present research momentum, the development of efficient and stable ambient air-processed perovskite solar cells (PSCs) is of the core interests of scientists dealing with perovskites for photovoltaics. Hitherto, many suitable approaches are proposed to this aim. However, according to the authors' knowledge, none of them deals with the study of the underlying mechanisms of how the temperature of perovskite precursor solution during its dripping on the substrate influences the characteristics of fully ambient air-processed PSCs. The present work demonstrates the dripping temperature control of perovskite precursor solution as a critical facile and universal approach in realizing high-humidity fabrication of PSCs. Herein, important observations regarding the effect of dripping temperature (from −20 °C to 100 °C) of MAPbI3 precursor solution on the characteristics of fully ambient air-processed perovskite layer and carbon-based hole transport material-free PSCs are unveiled and thoroughly discussed. The results indicate that the dripping temperature of perovskite precursor solution greatly affects the affinity of perovskite nuclei and substrate active sites, the hydrophilicity of solution, as well as the crystal and chemical structure, and morphology of the perovskite layer. Subsequently, the characteristics of PSCs vary, mainly regarding the charge transport and recombination rates, while their hysteretic behavior also changes. The investigation demonstrates that a significant enhancement in the PSCs performance can be achieved by the proposed approach.