A Fully Printable Hole-Transporter-Free Semi-Transparent Perovskite Solar Cell

Perovskite solar cells (PSCs) have gained tremendous attention owing to their promising photovoltaic performance, surpassing all the alternative technologies based on solution-processed materials. PSCs displaying record efficiencies contain hole transporting material (HTM) and gold back contact, which are too expensive for large-scale deployment. Although the HTM-free PSCs have been reported, a few can be used in tandem configuration, an architecture that is warranted to commercialize PSCs. This work presents, to the best of our knowledge, the first HTM-free and Au-free PSCs that are semi-transparent in the IR region (desired for tandem cells) with an efficiency of 8.3 %. We systematically investigate the effect of varying the thickness of active and charge conducting layers on the photovoltaic performance of PSCs. Besides, semitransparency, another advantage of the scaffold is its simplicity: a fully printable mesoporous structure consisting of a TiO2 layer (400 nm), Al2O3 as a separator layer (500 nm) and tin-doped indium oxide (ITO) layer (5 mu m), rendering our work highly pertinent for upscaling and large-scale applications.