Perovskite solar cells on paper and the role of substrates and electrodes on performance

The first perovskite solar cell (PSC) fabricated directly on a paper substrate is here reported delivering a maximum power conversion efficiency of 2.7%. The paper PSCs (PPSC) were developed with a lowtemperature paper/Au/SnO2/meso-TiO2/CH3NH3PbI3/Spiro-OMeTAD/MoOx/ Au/MoOxarchitecture utilizing Au/SnO2and MoOx/Au/MoOxstacks as electronand holeextracting electrodes respectively. The transparent MoOx/Au/MoOxelectrode had a favourable combination of transmittance (62.5%) and sheet resistance (9 Ω/□). By comparing performance of cells on paper with those fabricated on glass and plastic films with different electrodes, we identify avenues to guide future improvements. All deposition processes are scalable and compatible with large area printing or evaporation technologies. Paper represents a lightweight, flexible, inexpensive, ubiquitous, and environmentally friendly cellulosic material, paving the way for integrating perovskite technology with other electronic components as well as for the development of independent light-harvesting photovoltaic devices on recyclable and low-cost cellulose paper substrates.