| 초록 |
While a number of synthesis methods have been reported to prepare perovskite solar cells with good device performance, it has not been well studied how they affect the properties of perovskite layers and devices. Here we report on various device characterizations of perovksite solar cells prepared by different synthesis methods. Solar cells with perovkiste absorbers with compact thin film-like morphology are prepared by both one-step and two-step processes, which exhibit comparable efficiencies at room temperature. However, temperature-dependence of device parameters is markedly different between the devices prepared by one-step and two-step processes. The two-step processed sample exhibits the significant collapse of efficiency as temperature is reduced below 300K because of diverging series resistance of the device, but the efficiency recovers as temperature is raised back to 300K. Once the device is heated to 340K, the device suffers from irreversible degradation. By contrast, the one-step processed sample shows a much milder degradation of efficiency at low temperatures and does not experience the irreversible damage at ~340K. We will discuss possible reasons behind the different temperature-dependence of the perovskite devices. Additionally, comparison of different device architectures—standard vs. inverted—focusing on electrical characterization is studied and it reveals that transport of electrons, but not holes, is what limits a total collected photocurrent. Details of the comparison will be presented. |
