Minimizing Energy Loss via Perovskite Heterostructure Fabricated by Transfer Printing Technique for Efficient Perovskite Solar Cells

Despite the efficiency of perovskite solar cells (PSCs) has been increased rapidly from 3.9% in 2009 to 25.7% in 2022, the conversion of solar energy into electricity is still not efficient enough due to the energy loss originates from the non-absorption of low-energy photons and thermalization losses of high-energy photons ascribed to the Shockley-Queisser limit. As a result, stacked perovskite architectures including tandem, heterostructure, and prismatic configurations have been proposed to minimize non-absorption and thermalization losses. However, fabricated multi-layer heterostructure through solution process suffers from the dissolution problem in which bottom layer will be destroyed by subsequently deposited perovskite layers. In this work, a grafting-assisted PDMS transfer process was demonstrated for constructing heterostructure perovskite layers for solar cell devices. As a proof of concept, an layer MAPbSnI₃was stacked on top of an MAPbBrI₂ layer to fabricate a cascaded heterostructure-based cell. The MAPbBrI₂/MAPbSnI₃ heterostructure showed power enhancement of ∼15% as compared to single-layer films MAPbBrI2 (∼13%) and MAPbSnI₃ (∼10%), presumably because of minimized thermodynamic and non-absorption losses. Such printed heterostructures suggest a new pathway for minimizing thermalization and non-absorption losses in PSCs and resolving the bottleneck of solution-processable perovskite heterostructures for the realization of efficient perovskite optoelectronics.