Description
Perovskite solar cells (PSCs) have become increasingly prominent as a promising route within the photovoltaics field owing to their attractive combination of cost-effective, high-power conversion efficiencies and tuneable bandgaps. Among them, carbon-based perovskite solar cells (C-PSCs) are rapidly gaining recognition as a highly exciting architecture for realizing low-cost, stable, scalable photovoltaics. Nevertheless, there are some challenges in C-PSCs which can be classified into three categories : First, the conductivity of carbon electrodes is lower than that of metals; second, they present a higher density of both macroscopic and microscopic defects, which notably trap and scatter charges; and third, there is an energy level mismatch between the carbon electrodes and adjacent layers. Although various approaches have been developed to improve cell efficiency, such as compositional engineering, interface engineering, and solvent engineering, the purpose of these strategies is to reduce fundamental energy losses and enhance carrier extraction at the interface. In this work we fabricated hole transport layer (HTL)-free C-PSC and deposited passivation layer 4-Flurophenethylammonium bromide on top of perovskite. This passivation layer has been incorporated to reduce the energy level mismatch between carbon and the perovskite layer. Furthermore, we exploited the piezo-phototronic effect (PPE) by applying compressive and tensile strain to the overall device, leveraging the piezoelectric polarization charges at the perovskite interface modulate the energy barrier. That polarization charges enhancing or reducing charge carriers and supresses or increases recombination. The synergistic combination of interfacial passivation and the PPE resulted in a significant enhancement in power conversion efficiency (PCE), increasing from 10.8% to 13.1%. These findings demonstrate, for the first time in an HTL-free carbon-based architecture, that coupling surface passivation with piezo-phototronic modulation offers a novel, low-cost strategy to enhance PSC performance, opening new avenues for strain-engineered, self-powered, and mechanically tuneable photovoltaic devices.
| I am the presenting author | Yes |
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