In-situ defect passivation assisted three-step printing of efficient and stable formamidine-lead bromide solar cells

Perovskite solar cells (PSCs) emerge as the most promising photovoltaics (PV) for their high performance and potential convenient cost-effective production routes comparing to the sophomore PV technologies. The printed PSCs with simplified device architecture and fabrication procedures could further enhance the competitive strength of PSC technology. In this work, we present an in-situ defect passivation (ISDP) assisted full-printing of high performance formamidine-lead bromide (FAPbBr3) PSCs. Only three rapid printing steps are involved for electron transporting layer (ETL), perovskite and carbon to form a complete solar cell on the low-cost fluorine-doped tin oxide (FTO) substrate. Long-chain polymer monomethyl ether polyethylene glycol is particularly utilized as the ISDP passivator, leading to conformal coating on the rough FTO and defect passivation for both ETL and perovskite during printing. A high efficiency of 10.85% (certified 10.14%) and a high Voc up to 1.57 V are achieved for the printed device. The unencapsulated PSCs maintain above 90% of the initial efficiency after continuously heating at 85 °C for 1000 h and over 80% of the efficiency after the maximum power point tracking for 3500 h. The fully printed semitransparent PSCs with carbon grids (CGs) shows average visible light transmittance over 33% and an efficiency of 8.81%.