Flexible Perovskite Solar Cells and Supercapacitors Integrated in a Photocapacitor— A Route Towards Self-Powered Portable and Wearable Electronics

The conceptual idea of the integration of energy photovoltaic (PV) generation and storage systems in a single unit simultaneously is a powerful means to use energy more efficiently specially under discontinuous illumination, improving the system performance, reducing device size and weight. Lightweight, bendable integrated PV devices and storage systems can be used in various applications, such as transportable electronic chargers, flexible displays, biomedical devices, conformable sensors, and wearable electronic textiles, attracting significant attention both from the scientific and industrial community.<br/>In this context, the emerging technology of flexible perovskite solar cells (f-PSCs) plays a fundamental role with a record power conversion efficiency above 25 %^[1] under 1 sun illumination and furthermore, they reached remarkable efficiency of 32.5% under indoor illumination at 1000 Lux ^[2].<br/>Flexible supercapacitors (f-SCs), on the other hand, are the best candidates for the storage in low power, portable electronics, as they offer several advantages over conventional Li-ion batteries (LiBs), such as lightweight, smaller size, longer life time (f-SC &gt; 30,000 h vs battery &gt; 500 h), and higher power density ^[3,5]. Their compactness not only facilitates portability and convenience for the end-user but also allows for better integration into diverse electronic ecosystems without imposing spatial constraints.<br/>In this presentation, the fabrication of f-PSCs will be reported showing our latest results on the scaling up process from solar cells to modules using sustainable printing techniques ^[6-8]. We will also report on our latest results on f-SC fabricated on flexible paper substrates using sustainable materials and printing techniques ^[9].<br/>Finally, the integration of the two devices will be shown in a in a hybrid photosupercapacitor. In this device, the supercapacitor showcases remarkable stability and a coulombic efficiency of 100%. Through a hybrid bifurcated structure designed to enhance their applicability, the supercapacitors were connected in series, and neatly layered on a paper substrate with the solar module strategically placed on top. The device quickly reached saturated voltage value with exposure to various light intensities such as 1 sun, 1000 lx, 500 lx and 200 lx and displayed a self-discharge beaviour which lasted more than two minutes. With peak overall and storage efficiencies determined to be 2.8% and 23% respectively. with an extensive potential window of 3.8 <i>V</i>, making it an prominent choice for real time application in electronic systems^[10].<br/><br/>References<br/>[1] N. Ren et al. <b> </b>iEnergy, Volume: 3, Issue: 1, March 2024<br/>[2] Z. Skafi et al, Solar RRL, Volume7, Issue20, October 2023<br/>[3] A. Patra, et.al. J. Mater. Chem. A 2021, 9, 25852<br/>[4] W.Raza et al., Nano Energy 2018, 52, 441-473. https://doi.org/10.1016/j.nanoen.2018.08.013<br/>[5] C. V.V.Muralee Gopi et al. Journal of Energy Storage, (2020),Vol. 27, 101035<br/>[6] B.Taheri et al. (2021) ACS Applied Energy Materials, doi.org/10.1021/acsaem.1c00140<br/>[7] F. De Rossi et al. Journal of Power Sources, (2021) Volume 494, 229735.<br/>[8] F. Jafarzadeh et al., Sust. En. & Fuels, 2023, 7(9), 2219-2228. https://doi.org/10.1039/D2SE01678H.<br/>[9] G. Polino et al. (2020) Energy Technology, doi.org/10.1002/ente.201901233<br/>[10] H.J. Lomeri et al., submitted manuscript