Hybrid SnO2/g-C3N4 layers with plasma-induced modifications for enhanced charge transport in perovskite solar cells

Abstract

The design of high-performance perovskite solar cells (PSCs) for indoor applications requires precise interface engineering to optimize charge extraction, particularly under low-light intensity conditions, where excess carrier density is limited. To enhance the charge extraction properties in PSCs, various carbon-based nanomaterials with varying functional groups have been utilized as electron transport layer (ETL) additives to address the issue with limited success. Thereby, in this work, we introduce a plasma-modified graphitic carbon nitride (GCN_PT) as an ETL interface layer additive which is deposited onto the SnO₂ electron transport layer to enhance electron extraction. Plasma modification transforms randomly distributed GCN particles (200–500 nm) into uniformly sized nanoparticles (1–3 nm) while inducing partial graphitization, significantly improving conductivity and charge transport properties. These modifications enable more efficient extraction and transport of photogenerated carriers at the SnO₂/GCN_PT interface, substantially enhancing short-circuit current density (J_SC). This improvement is particularly pronounced under low-light indoor conditions, where reduced photon flux limits carrier generation within the perovskite layer. Notably, under 1000 lux indoor white LED illumination, the optimized SnO₂/GCN_PT interface achieves a power conversion efficiency of approximately 39.80%, demonstrating its potential to advance indoor photovoltaic applications through enhanced J_SC and interface optimization.