Elucidating the photovoltaic performance of iodide-capped lead sulfide colloidal quantum dots as an active layer for next-generation solar cells

Lead sulfide (PbS) colloidal quantum dots (CQDs) are contemplated as a glaring contender for solution-processable photovoltaic (PV) technology. Exceptional power conversion efficiency (PCE) for colloidal quantum dots solar cells (CQDSCs) has been reported for the last decade. CQDSCs acquire alluring properties such as low-temperature processing and exhibit maximum absorption of the solar spectrum. The long-term stability of CQDSCs, however, impedes their industrial application, specifically when they are exposed to sun-like radiance in ambient conditions. Here, the study was conducted on the iodide-capped lead sulfide (PbS-I) quantum dots (QDs) based solar cell to explore the air stability and photo-induced degradation of the device using one sun-simulated illumination. X-ray diffraction (XRD) reveals the structural properties of the PbS-I, and optical properties were studied utilizing UV–Vis, and photoluminescence (PL) spectroscopies. To confirm whether the energy levels of the electron transport layer (ETL) and active layer (PbS-I) for the fabrication of the device are suitable, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) tests were embraced. Further, the photovoltaic (PV) execution of fabricated devices was investigated by the current–voltage (J-V) characteristics and impedance spectroscopic (IS) study. The device yielded PCE up to 10.7 % with a short circuit current density (JSC) of 24.2 mA.cm−2 and maintained its performance more than 80 % after 336 hrs.