Fig. 1. (Color online) (a) Chemical structure of PAPMS, MPTMS and IPTMS passivation layer used in this work. (b) Schematic illustration of the formation process of perovskite films based on a sequential deposition. (c) XPS spectra of Pb 4f for the perovskite films with and without siloxane treatment. (d) XRD pattern of perovskite films with and without siloxane treatment.

Fig. 2. (Color online) Photovoltaic performance distribution of PSCs with different termination groups of methoxysilane (a) PCE, (b) open-circuit voltage (V_oc), (c) short-circuit current density (J_sc), (d) fill factor (FF) for control, PAPMS, MPTMS and IPTMS devices. (e) Current density−voltage (J−V) curves of the control device and self-cross-linking devices with PAPMS, MPTMS, and IPTMS. (f) EQE spectra for the control and IPTMS devices. (g, h) Steady-state power output for the best-performing of (g) control and (h) IPTMS device.

Fig. 3. (Color online) (a) PL emission intensity mapping of control, PAPMS, MPTMS and IPTMS treated films. (b) EIS spectra of devices based on the pristine and IPTMS treatment. (c) Normalized TPC decay curves for control- and IPTMS-treated devices. (d) Dark I−V curves of devices with the structure of ITO/perovskite/Au for the control and IPTMS treated film.

Fig. 4. (Color online) Long-term thermal stability of unsealed devices based on pristine, MPTMS and IPTMS treatment (a) PCE, (b) V_oc, (c) J_sc and (d) FF.