CsPbI3-perovskite quantum dot solar cells: unlocking their potential through improved absorber layer characteristics and reduced defects

Abstract

Perovskite quantum dots (CsPbI3-PQDs), a translucent material, have gained great interest in the PV industries owing to their unified virtues of perovskites and quantum dots. However, researchers have found that perovskite solar cells (PSCs) suffer from issues like low stability at high relative humidity, energy states imbalance, severe hysteresis, and an easy decomposition under ultraviolet (UV) radiation that severely restrict their industrialization. Quantum dots (QDs) are excellent materials with numerous admirable traits that have been extensively employed in PSCs to overcome the aforementioned problems. To achieve high performance of the examined device, the CsPbI3-PQDs has been stacked between two charge transport layers, i.e., Cl@SnO2 (to facilitate electrons towards cathode) and P3HT (to facilitate holes towards anode). In this context, study of variations in different parameters such as thickness and acceptor density of the CsPbI3-PQDs absorber layer has been done. After varying the thickness and acceptor density of the CsPbI3-PQDs layer, the cell’s performance is optimized at thickness of 400 nm and acceptor density of 1 × 1017/cm3 delivering higher PV parameters power conversion efficiency (PCE):16.17%, open circuit voltage (VOC):1.02 V, short circuit density (JSC):18.06 mA cm−2 and fill factor (FF): 87.06% respectively. Thereafter, the effects of bulk defects in CsPbI3-PQDs and the interface between CsPbI3-PQDs and Cl@SnO2 have been explored in this work. For the cell to work at its best, the bulk defect density and interface defect density, respectively, should not be more than 1 × 1014 /cm3 and 1 × 1013 /cm2. Afterwards, a comprehensive study has been done by varying the front electrode transparency (from 40% to 95%) to improve the device performance. With 95% of front electrode transparency, the performance of device is improved due to increase in the photon coupling.