Gujar Tanaji P, Unger Thomas, Schönleber Andreas, Fried Martina, Panzer Fabian, van Smaalen Sander, Köhler Anna, Thelakkat Mukundan
Applied Functional Polymers, Macromolecular Chemistry I, University of Bayreuth, 95447 Bayreuth, Germany.
Phys Chem Chem Phys. 2017 Dec 20;20(1):605-614. doi: 10.1039/c7cp04749e.
We report a systematic investigation on the role of excess PbI content in CHNHPbI perovskite film properties, solar cell parameters and device storage stability. We used the CHNHI vapor assisted method for the preparation of PbI-free CHNHPbI films under a N atmosphere. These pristine CHNHPbI films were annealed at 165 °C for different time intervals in a N atmosphere to generate additional PbI in these films. From XRD measurements, the excess of PbI was quantified. Detailed characterization using scanning electron microscopy, X-ray diffraction, UV-Visible and photoluminescence for continuous aging of CHNHPbI films under ambient condition (50% humidity) is carried out for understanding the influence of different PbI contents on degradation of the CHNHPbI films. We find that the rate of degradation of CHNHPbI is accelerated due to the amount of PbI present in the film. A comparison of solar cell parameters of devices prepared using CHNHPbI samples having different PbI contents reveals a strong influence on the current density-voltage hysteresis as well as storage stability. We demonstrate that CHNHPbI devices do not require any residual PbI for a high performance. Moreover, a small amount of excess PbI, which improves the initial performance of the devices slightly, has undesirable effects on the CHNHPbI film stability as well as on device hysteresis and stability.
我们报告了一项关于过量PbI含量在CHNHPbI钙钛矿薄膜特性、太阳能电池参数及器件存储稳定性中作用的系统研究。我们采用CHNHI气相辅助法在氮气气氛下制备无PbI的CHNHPbI薄膜。这些原始的CHNHPbI薄膜在氮气气氛中于165℃下退火不同时间间隔，以在这些薄膜中生成额外的PbI。通过X射线衍射测量对过量的PbI进行了定量。使用扫描电子显微镜、X射线衍射、紫外可见光谱和光致发光对CHNHPbI薄膜在环境条件（50%湿度）下的持续老化进行了详细表征，以了解不同PbI含量对CHNHPbI薄膜降解的影响。我们发现，由于薄膜中存在的PbI量，CHNHPbI的降解速率加快。对使用具有不同PbI含量的CHNHPbI样品制备的器件的太阳能电池参数进行比较，结果表明其对电流密度-电压滞后以及存储稳定性有很大影响。我们证明，CHNHPbI器件实现高性能并不需要任何残留的PbI。此外，少量过量的PbI虽然会略微提高器件的初始性能，但对CHNHPbI薄膜稳定性以及器件滞后和稳定性有不良影响。
