Extended Data Fig. 9: Time-of-flight secondary ion mass spectrometry (TOF-SIMS) measurements.
From: Multifunctional ytterbium oxide buffer for perovskite solar cells
TOF-SIMS depth profiles of the BCP- or YbOx-based PSCs with and without ageing. a, c, Control (with the BCP buffer layer) and target device (with the YbOx buffer layer), respectively. b, d, TOF-SIMS profiles of both control and target devices after ageing at 85 °C for 200 h in the N2 atmosphere, respectively. The highlighted secondary ion distribution: 1: Cs+; 2: Rb+; 3: Cu+, 4: I+; 5: Br+.
