Halide perovskite solar cells

• Main Author: Eng, Jia Ler
• Other Authors: Nripan Mathews
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2024
• Subjects: Engineering; Perovskite
• Online Access: https://hdl.handle.net/10356/181529
• Institution: Nanyang Technological University

Since its inception in 2009, research on Perovskite Solar Cells, a 3rd generation photovoltaic technology has matured with its noticeable increase in PCE from the first peer-reviewed published paper at 3.8% [1] to 26.0% [2] in 2024. The current focus for perovskite research has been towards realising potential to commercialize perovskite, primarily focusing on developing scalable and large area perovskite film deposition techniques and film quality performance using slot-die coating deposition technique [1,2,3] due to the performance variation between large-area commercialised, industrially produced perovskite solar cells and lab-scale, small-area spin-coated perovskite solar cells. From a material standpoint, to ensure that film quality of perovskite film maintains or improves as perovskite film formation area scales up, it is important to outline, investigate and modulate the nucleation and crystallization profile of slot-die coated, solution-processed perovskite films during wet film evolution. Solution engineering, specifically investigating its solvent system, has been a well-established approach but there are no systematic studies to assess the effects of adding varying volume ratios of different solvent precursors and how it affects the quality of perovskite films. As such, we have identified a gap in research by outlining a systematic study to investigate the effects of N-methyl-2-pyrrolidone (NMP) as a co-evaporating solvent as part of the DMF:NMP binary solvent system on slot-die coated, solution-processed perovskite films to modulate perovskite film formation in terms of its coating abilities and subsequently assess its subsequent perovskite film quality (homogeneity, crystallinity and film morphology). By quantifying and assessing the processing window of each phase transition (sol-gel and crystallization) of formamidinium caesium lead triiodide (FACsPbI3) precursor ink, coupled with the coating capabilities of the ink, we can conclude that the most suitable and robust DMF:NMP solvent system precursor ink to achieve higher quality films arises from a more volatile precursor solution, specifically at a DMF:NMP ratio at 8:1.