| 초록 |
Large area scaling of hybrid perovskite is essential to bring the technology into commercialization. Various large-scale printing techniques have been successfully employed to fabricate high performance perovskite solar cell. In particular, solution shearing is a versatile technique in which many processing parameters can be tuned in order to produce films with desired structure and morphology. In this study, we have examined the impacts of substrate temperature and coating speed, two of the most influential process parameters, on morphology of the resultant perovskite films. Four distinct phases are identified and a morphology-phase map is constructed with the aforementioned parameters. Formation of these phases was attributed to a delicate balance between supersaturation rate and supply of solution to the meniscus, which dictated the nucleation and the crystal growth process. Through optical analysis, an optimal phase window is chosen and the device performance with the chosen condition exhibits power conversion efficiency over 15%, which is comparable to a reference device prepared by the conventional spin-coating process. A uniform perovskite film of an area ＞ 55 cm2 is prepared with solution shearing. Several small-area devices from different locations of the large-area films shows uniform efficiencies with deviation coefficient of 4.2%, illustrating the good uniformity achievable with our solution shearing techniques. |
