IMPROVED PERFORMANCES OF CSPBBR3 PEROVSKITE SOLAR CELLS USING HYDROXYETHYL CELLULOSE (HEC) AS PASSIVATION AGENT

• Main Author: Fitri Rusliani, Prima
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/86692
• Institution: Institut Teknologi Bandung

This study focuses on optimizing the performance of CsPbBr3 inorganic perovskite solar cells without the use of hole transport material (HTM-free) through the addition of a hydroxyethyl cellulose (HEC) polymer passivation agent. The main purpose of this study is to overcome the problem of poor morphology of the perovskite layer and the cause of low power conversion efficiency (PCE). Variations of experiments have been carried out by modifying several parameters, including: (1) The position of the passivation layer, where HEC is deposited both before and after the perovskite layer to identify the optimal position that can maximize the passivation effect, (2) HEC solvents, namely chlorobenzene and terpineol to study the effect of solvent polarity on solar cell performance, (3) HEC concentration of 0.25 mg/mL, 0.5 mg/mL, and 1.0 mg/mL to determine the optimal concentration that can improve performance without compromising the optical and electrical properties of the solar cell. The solar cell fabrication process is carried out in environmental conditions with a relative humidity of 50-60%. In-depth characterization was carried out using various techniques, such as X-Ray Diffraction (XRD), scanning electron microscope (SEM), fourier transform infrared spectroscopy (FTIR), UV-Vis spectroscopy, photoluminescence (PL), electrochemical impedance spectroscopy (EIS), and solar simulator filter AM 1.5 G 100 mW/cm2. The results of this study showed that the addition of HEC significantly increased the performance parameters of CsPbBr3 solar cells with the highest increase reaching PCE of 5.78%, Voc of 1.37 V, Jsc of 5.54 mA/cm2, and fill factor (FF) of 75.80% when compared to control cells. XRD analysis showed an increase in peak intensity, indicating an increase in the crystallinity of the perovskite layer. SEM images reveal that HEC can fill in the gaps at the perovskite grain boundary, reducing defects and improving the morphological quality of the layer. FTIR spectroscopy confirms the interaction between the hydroxyl group of HEC and the surface of perovskite. PL and EIS measurements showed a decrease in the non-radiative recombination rate and an increase in recombination resistance indicating a decrease in trap density in the perovskite layer. This study successfully showed that the addition of HEC passivation agent is an effective strategy to improve the performance of CsPbBr3 perovskite solar cells. Optimization of the position of the passivation layer, selection of solvents, and the right concentration of HEC are essential to achieve optimal results. The mechanism of improving the performance of solar cells can be explained through the morphology of the perovskite layer, the decrease in trap density, and the reduction of the recombination rate. The results of this study make a significant contribution to the development of more efficient perovskite solar cells. Further research can be carried out by testing the stability of cells over a certain period against several stability parameters and perform further characterization to validate the contribution of HEC to CsPbBr3 perovskite solar cells.