“…It can undergo oxidation and degradation when exposed to air and light. 30 To overcome the stability and cost issues, researchers have been actively investigating other organic materials as potential HTLs including PEDOT: PSS, 31 PTAA, and P3HT. 30 Hence, we evaluated the PV outputs of the PSCs using spiro-OMeTAD, P3HT, and Cu 2 O as HTLs and TiO 2 , 32 which is mostly utilized as an n-type ETL in PSCs due to its ease of production, excellent charge transfer capacity, and chemical stability, being used as the lone ETL.…”