Oriented Growth for Efficient and Scalable Perovskite Solar Cells by Vapor-Solid Reaction

The precise control and understanding of crystal orientation in perovskite polycrystalline films are crucial for the development of efficient and stable devices. However, achieving this control remains a significant challenge. Herein, a PbI2 oriented growth strategy is developed, combined with in situ vapor-solid reaction transformations, to achieve oriented growth of full-vacuum perovskite films. Grazing-incidence wide-angle X-ray scattering (GIWAXS) analysis revealed the general pattern of PbI2 oriented vapor growth and in situ vapor-solid reaction transformation in this two-step process. The resulting preferred orientation has effectively reduced trap state density, optimizing the carrier dynamics. As a result, champion efficiencies of 22.11% (0.148 cm2), 20.60% (1 cm2), and 19.41% (5 x 5 cm2 mini-modules) are achieved, which are the highest value for perovskite based on vapor-solid reaction. Additionally, the oriented growth method is applicable to a variety of guide layers and is extended to 30 x 30 cm2 film, demonstrating the universality and scalability of the method. Crystal orientation is reported to affect the optoelectronic properties of perovskite films. Here, the orientation control of vapor-deposited perovskites is achieved by the oriented growth of the PbI2 precursor, and the mechanism is investigated by the Grazing-incidence wide-angle X-ray scattering (GIWAXS) technique. Further, as a full vapor-phase process, this method has been successfully extended to the fabrication of large-area perovskite films and devices. image