Strategies to improve P-I-N perovskite solar cell performance

This thesis comprises of an introduction aiming to introduce the reader to the world of halide perovskite solar cells. The following three chapters focus on the optimization of perovskite solar cell (PSC) systems with p-i-n architecture to enhance its efficiency and stability. Conclusion is presented in the last chapter. After the introductory first chapter, the second chapter presents a comprehensive screening method to optimize a p-i-n architecture with Poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) as a hole-transport layer. Concentration-dependent screening and molecular weight analysis of PTAA revealed optimal conditions resulting in a promising power conversion efficiency (PCE) of 17.06%. Overcoming challenges related to perovskite deposition on the hydrophobic surface of PTAA, innovative approaches, including PTAA treatment and the introduction of PFN-Br, led to improved wettability and enhanced photovoltaic parameters. The third chapter explored optimal perovskite designs for improved photovoltaic devices, employing PTAA and Poly[(9,9-bis(3'-((N,N)). -)) in. dimethyl).)-N-ethylammonium)-propyl)2,7- fluorene) -alt-2,7-(9,9-dioctylfluorene)]dibromide (PFN-Br). The use of ionic liquid (BMIMBF4), Oleylamine (OAm), and benzylhydrazine hydrochloride (BHC) additives in the perovskite solution positively impacted various photovoltaic parameters, suggesting a promising avenue for enhancing the efficiency and stability of inverted perovskite solar cells. It is then continued with comparisons between self-assembled monolayers (SAMs) and PTAA in the p-i-n configuration set the stage for a more detailed analysis in the next chapter, exploring the possibility of using SAMs and introducing small organic interlayers. The fourth chapter introduces a highly effective approach to interfacial engineering for more efficient and stable perovskite solar cells. By strategically introducing the small organic molecule C10-BTBT as an interlayer, a significant enhancement in charge extraction was observed, resulting in a remarkable increase in the fill factor and power conversion efficiency. Importantly, this enhancement was achieved without inducing changes to the layers involved in PSC fabrication, emphasizing the primary impact on charge extraction. Experimental results and density functional theory (DFT) calculations support this novel interlayer insertion technique as a practical and versatile technology compatible with various PSC architectures, holding great potential for further advancements in perovskite photovoltaics.