Structurally Stabilized Hydrogen-Bonded Bridging Networks for Defect-Passivated Cesium Lead Iodide Perovskite Quantum Dot Photovoltaics

초록

Lead-halide perovskite quantum dots (PQDs) are promising materials for next-generation photovoltaics (PVs). However, the fabrication of dense PQD films induces volume contraction and residual stress, generating undercoordinated surface defects that limit device performance and stability. To address these limitations, a bifunctional ligand, 4-(1H-imidazol-2-yl)benzoic acid (4-ImBA), was designed to concurrently passivate surface defects and establish a dynamic hydrogen-bonded bridging network. In contrast to conventional passivation strategies, this network is likely to alleviate internal stress accumulated during film assembly, thereby contributing to the suppression of further defect generation. The 4-ImBA-passivated device achieved a 1-sun power conversion efficiency (PCE) of 14.5% (vs. 13.0% control) and an indoor PCE of 38.4% (vs. 34.2% control) (6500 K LED, Irradiance: 0.291 mW cm-2), retaining 88% of its initial PCE under ambient conditions. Extending this strategy to luminescent solar concentrators (LSCs), the enhanced photoluminescence quantum yield produced a high external quantum efficiency of 33.56%, yielding a total LSC-PQD PV module efficiency of 7.9% under indoor LED illumination (Irradiance: 0.291 mW cm-2). These results demonstrate that hydrogen-bonded networks within a hybrid perovskite quantum dot platform represent a robust strategy for stable PQD optoelectronics.

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