Highly efficient perovskite solar cells for light harvesting under indoor illumination via solution processed SnO2/MgO composite electron transport layers

• Published in: Nano energy Vol. 49; pp. 290 - 299
• Main Authors: Dagar, Janardan, Castro-Hermosa, Sergio, Lucarelli, Giulia, Cacialli, Franco, Brown, Thomas M.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.07.2018
• Subjects: Electron transport layer; Indoor light illumination; Maximum power density; Planar perovskite solar cell; SnO2 layer; SnO2/MgO composite layer; SnO2/MgO composite layer; SnO2 layer; Planar perovskite solar cell; Electron transport layer; Maximum power density; Indoor light illumination
• ISSN: 2211-2855
• DOI: 10.1016/j.nanoen.2018.04.027

We present new architectures in CH3NH3PbI3 based planar perovskite solar cells incorporating solution processed SnO2/MgO composite electron transport layers that show the highest power outputs ever reported for photovoltaic cells under typical 200–400 lx indoor illumination conditions. When measured under white OSRAM LED lamp (200, 400 lx), the maximum power density values were 20.2 µW/cm2 (estimated power conversion efficiency, PCE = 25.0%) at 200 lx and 41.6 µW/cm2 (PCE = 26.9%) at 400 lx which correspond to a ∼ 20% increment compared to solar cells with a SnO2 layer only (even at standard 1 sun illumination, where the maximum PCE was 19.0%). The thin MgO overlayer leads to more uniform films, reduces interfacial carrier recombination, and leads to better stability. All layers of the cells, except for the two electrodes, are solution processed at low temperatures for low cost processing. Furthermore, ambient indoor conditions represent a milder environment compared to stringent outdoor conditions for a technology that is still looking for a commercial outlet also due to stability concerns. The unparalleled performance here demonstrated, paves the way for perovskite solar cells to contribute strongly to the powering of the indoor electronics of the future (e.g. smart autonomous indoor wireless sensor networks, internet of things etc). [Display omitted] •Perovskite solar cells incorporating new solution-processed SnO2/MgO composite ETLs.•The thin MgO overlayer enhances efficiency by ~20%, reducing charge recombination.•Maximum PCE of 19.0% under 1 sun illumination with a stabilized value of 18.1%.•Maximum power density: 20.2 µW/cm2 at 200 lx; 41.6 µW/cm2 at 400 lx (PCE = 26.9%).•Highest power outputs ever reported under typical 200–400 lx indoor illumination.