Compositional and Interface Engineering of Hybrid Metal Halide Perovskite Thin Films for Solar Cells

Abstract: Perovskite solar cells (PSCs) are the fastest-growing photovoltaic (PV) technology in the solar cell community and have reached an efficiency close to that of commercial silicon (Si) solar cells. The organic-inorganic halide perovskite solar cell is an emerging PV technology and grabbed much attention due to its low cost, high efficiency, and ease of fabrication at lower temperatures 100-200 C by solution-processed spin coating or thermal evaporation techniques. Further, we introduce a self-assembled monolayer (SAM) based hole transport layer (HTL) in the p-i-n device architecture PSC. In this work, we used the mixing engineering strategy of SAM with a conjugated polyelectrolyte. We dealt with the hydrophobicity and tailored the work function of the mixed SAM based HTL. Therefore, the HTL/perovskite interface is engineered, and associated device physics is discussed. In addition, we observed the lowest dark current for specific mixed (9:1) HTL, which is a prerequisite in photodetector applications. Therefore, a detailed photodetection analysis is discussed to study the scalable photodetector device. This thesis thoroughly studies perovskite compositional and interface engineering via various optoelectronic measurements. An in-depth device physics is discussed to study the interfacial defects between the charge transport and the perovskite layers. This thesis will be helpful in exploring a new class of perovskite materials and interface modification engineering for fabricating reproducible, stable, and highly efficient hybrid organic-inorganic metal halide perovskite solar cells.