Contribution: LPEM
Reference : Small. 2024, 2401505, https://doi.org/10.1002/smll.202401505 (Early view)
DOI : https://doi.org/10.1002/smll.202401505
Contacts : zhuoying.chen@espci.fr
Abstract :
The achievement of both efficiency and stability in perovskite solar cells (PSCs) remains a challenging and actively researched topic. In particular, among different environmental factors, ultraviolet (UV) photons play a pivotal role contributing to device degradation. In this work, by harvesting simultaneously both the optical and the structural properties of bottom-up-synthesized colloidal carbon quantum dots (CQDs), we provide a cost-effective means to circumvent the UV-induced degradation in PSCs without scarification on their power conversion efficiencies (PCEs). By exploring and optimizing the amount of CQDs and the different location/interfaces of the solar cells where CQDs are applied, we achieve a synergetic configuration where the photovoltaic performance drop due to optical loss is completely compensated by the increased perovskite crystallinity due to interfacial modification. As a result, on the optimized configurations where CQDs were applied both on the exterior front side as an optical layer and at the interface between the electron transport layer and the perovskite absorber, unencapsulated PSCs with PCEs > 20% are fabricated which can maintain up to ~ 94% of their initial PCE after 100 hours of degradation in ambient air under continuous UV illumination (5 mW cm-2).
Left : Schematic illustrating the combined exterior and interfacial application of bottom-up synthesized carbon quantum dots (CQDs) in a functional PSC structure. Right : Unencapsulated PSC stability under continuous UV illumination measured on devices without (control) and with CQDs applied under different configurations in air. This work highlights a cost-effective means based on CQDs to circumvent the UV-induced degradation in efficient perovskite solar cells (PSCs) without scarification on their power conversion efficiencies.
