(color online) Gaussian decomposition of the RIA spectrum of Sample-1 (blue line) with the Si-related defects from the literature and OH⁻ defects. The OA bands of different defects are shown as follows: PSC-STH-2 (pink line), PSC-STH-3 (green line), Si-NBOHC (black line), OH⁻ defect centered around 0.89 eV (purple line), and OH⁻ defect centered around 1.0 eV (cyan line). The contributions of other defects are negligible and not indicated.