Pei-En Fang¹, Ying-Hung Chen¹, Hsieh-Chih Chen², Ping-Yen Hsieh¹, Ju-Liang He^1
1Feng Chia University, Taichung City, Taiwan
²Fu Jen Catholic University, Taiwan
Perovskite solar cells (PSCs) have garnered significant attention due to their straightforward fabrication process, cost-effectiveness, and exceptional power conversion efficiency (PCE). Furthermore, the intrinsic mechanical flexibility and low-temperature solution processing of perovskite materials enable the production of flexible perovskite solar cells (f-PSCs). Numerous applications of f-PSCs are currently being explored, including their deployment on aircraft, vehicles, tents, and a variety of irregular or curved surfaces such as cylindrical pipes, where they can efficiently supply power. Also, the lightweight nature and ease of encapsulation of f-PSCs reduce transportation and installation costs, supporting the large-scale manufacturing and commercialization of f-PSC modules for widespread use.
Titanium dioxide (TiO₂) is the most widely studied electron transport layer (ETL) in PSCs due to its low cost, environmental friendliness, non-toxicity, excellent optical properties and chemical stability. However, the traditional TiO₂ fabrication process requires high-temperature sintering to achieve good crystallinity for the mesoporous and compact layers, which ensures proper energy level alignment and electron transport with the perovskite layer. This requirement limits its application in f-PSCs. In this regard, high-power impulse magnetron sputtering (HiPIMS) was employed to fabricate dense and compact TiO₂ as ETL under low deposition temperature condition. Experimental results show that the TiO₂ thin film can be successfully grown on the PET substrate without causing damage, exhibiting dense and crystallinic structure as validated by SEM and XRD analyses. Furthermore, a f-PSCs based on this HiPIMS-TiO_₂ ETL was prepared and evaluated its internal quantum efficiency (IQE), external quantum efficiency (EQE), and the overall PCE of the device. Additionally, the enhanced long-term stability of the f-PSC device based on the HiPIMS-TiO₂ ETL was recorded.