Perovskite-inspired Cu2AgBiI6 for mesoscopic indoor photovoltaics under realistic low-light intensity conditions

• Published in: Sustainable energy & fuels Vol. 7; no. 1; pp. 66 - 73
• Main Authors: G Krishnamurthy Grandhi, Toikkonen, Sami, Al-Anesi, Basheer, Pecunia, Vincenzo, Vivo, Paola
• Format: Journal Article
• Language: English
• Published: London Royal Society of Chemistry 01.01.2023
• Subjects: Circuits; Energy conversion efficiency; Illumination; Internet of Things; Light; Light emitting diodes; Light intensity; Lighting; Luminous intensity; Open circuit voltage; Perovskites; Photovoltaic cells; Photovoltaics; Recombination; Short circuit currents; Short-circuit current; Thickness; Titanium dioxide; Toxicity; White light
• ISSN: 2398-4902
• DOI: 10.1039/d2se00995a

The considerable potential of perovskite-inspired Cu2AgBiI6 (CABI) photovoltaics under both solar and artificial lighting has been recently highlighted. However, to realistically ensure the suitability of CABI-based indoor photovoltaics (IPVs) to power the Internet of Things (IoT) ecosystem, it is necessary to study how the device performance is affected by very low-light intensity conditions (200–50 lux illumination). In this work, we find that the fine-tuning of the mesoporous TiO2 (mp-TiO2) layer thickness is crucial to maximize the performance of mesoporous CABI-based IPVs at both high and very-low artificial light intensity as it directly affects the charge extraction and non-radiative charge recombination in the devices. An optimal mp-TiO2 thickness of ∼200 nm leads to an indoor power conversion efficiency (PCE(i)) of 5.52% and a fill factor of 69%, which are the highest values for perovskite-inspired based IPVs under 1000 lux white light-emitting diode lighting. Importantly, the devices keep a high fill factor also at very low-light intensity. This guarantees a noteworthy PCE(i) value of 4.64% at 200 lux and an open-circuit voltage (VOC) of 0.38 V even at 50 lux. Our work suggests that, upon further improvements in the short-circuit current and VOC values, low-toxicity mesoscopic CABI-based IPVs may approach their theoretical PCE(i) values of 50–60% even under very low-light intensity conditions.