Ambient processing of methylammonium lead iodide perovskite solar cells via magnetic field-assisted electrodeposition of the precursor film

One of the key strategies to develop halide perovskite solar cells involves the preparation of good quality perovskite layer. Although tackling the issues of perovskite crystallinity and morphology is central to ensuring high photovoltaic performance of the device, the feasibility of large-scale fabrication of perovskite is equally important. In this study, we argue that such aims can be achieved by using a new, scalable fabrication technique based on electrodeposition assisted by an external magnetic field to effectively prepare the high-quality PbI2 precursor and perovskite films. The magnetic field-assisted electrodeposition technique required only 10 min of preparation of the precursor layer, which was subsequently converted to improved perovskite films, as supported by the results from scanning electron microscopy, X-ray diffraction, UV-vis absorption, and photoluminescence. All preparation processes were carried out under ambient conditions with high humidity (50-75% relative humidity). Interestingly, using a simple hole transport layer-free device structure with a carbon back contact, the perovskite film prepared using the magnetic field-assisted electrodeposition method showed 4.2% power conversion efficiency, as well as 0.62 V in open-circuit voltage and 16.65 mA/cm(2) in photocurrent at AM 1.5 solar light of 100 mW/cm(2). Moreover, the unencapsulated perovskite device prepared using electrodeposition under the external magnetic field also demonstrated high stability under ambient conditions, revealing essentially unchanged power conversion efficiency after 14 days of fabrication. Taken together, this work provides an evidence in support of a relatively unexplored electrodeposition-based strategy as a rapid, facile, scalable, and potentially low-cost preparation of perovskite films for solar cells.