Sensitive detection of bilirubin using highly luminescent benzylamine capped CH3NH3PbBr3 perovskite quantum dots

Abstract

Luminescent organic–inorganic metal halide hybrid perovskite quantum dots (PQDs) as a new class of fluorophores are finding increasing attention towards chemical and biological sensing due to their exceptional photophysical properties. Herein, we synthesized highly fluorescent CH3NH3PbBr3 perovskite quantum dots (B-PQDs) through the ligand assisted reprecipitation method (LARP), using benzylamine as the surface capping ligand. Morphological and opto-structural properties of the as-synthesized B-PQDs were thoroughly investigated using high resolution transmission electron microscopy (HR-TEM), X-Ray diffraction (XRD), Fourier transform infra-red spectroscopy (FT-IR), UV–Vis absorption, and fluorescence spectroscopy. The as-synthesized electron-rich amine-capped B-PQDs were employed to study their sensing response towards bilirubin (BL). The aromatic amine capped B-PQDs enhance the sensory response towards BL due to the π-π interaction with BL’s conjugated system. The B-PQDs were found to be highly sensitive towards BL with a stern–volmer constant value ≈ 4.3 × 104 M−1 and limit of detection of 0.42 μM. A panel of characterizations were carried out to investigate the detailed sensing mechanism where resonance energy transfer was found to be the dominant quenching mechanism for BL detection. Our results demonstrated the potential for utilizing organic–inorganic halide perovskite quantum dots for sensing applications, through surface ligand modification tailored for detecting specific analytes.