Additives Effects on the Charge Carrier Dynamics and Performance Metrics of Formamidinium-Rich Mixed Lead Halide Perovskite Solar Cell

Koech, Kipyegon Richard (2022-02-23)


Perovskite solar cell (PSC) has emerged as a promising photovoltaic technology due to their prospects for high efficiency and low cost. Despite the impressive improvement in their power conversion efficiency (PCE) over the years, it is still limited by non-radiative recombination losses arising from the non-ideal material properties. Further, the rapid degradation in their PCEs when exposed to the ambient conditions is a great impediment to their commercialization. To address these challenges, there is a need to engineer the properties of the charge transport layers (CTLs), the active layer (AL) and the interfaces between them with a view to suppressing the non-radiative recombination and performance degradation pathways. In this work, an in-depth study of the effects of additives incorporated into the electron transport layer (ETL) and the AL on the optoelectronic properties and performance characteristics of Formamidinium (FA)-rich mixed lead halide PSC was carried out. The results of the study revealed that an appropriate proportion of additives in the ETL and/or the AL improve the PCE and stability of FA-rich PSC. Inparticular, the incorporation of 0.2 volume proportion of tin oxide (SnO2) into the titanium dioxide (TiO2)-based ETL improved the PCE by about 7.17%. Furthermore, the addition of Cesium bromide (CsBr) and Polyethylene Oxide (PEO) into the AL improved the morphology of the AL leading to simultaneous improvement in the PCE and stability of FA-rich PSC.