Visible-Blind Spectrally Selective Near-Infrared Photodetection with Enhanced Sensitivity

Near-infrared narrowband photodetectors (NPDs), renowned for their exceptional performance, are of great significance in applications spanning biosensing, health monitoring, and intelligent communication. In this research, we introduced a straightforward and versatile solution-processing approach for fabricating NPDs capable of near-infrared detection. This advancement is primarily driven by the integration of an independent organic optically selective layer (PM6:PTIC). Furthermore, we have incorporated a hybrid electron-blocking layer, composed of poly[(9,9-dioctylfluorenyl-2,7-diyl)-<i>alt</i>(4,4'-(<i>N</i>-(4butylphenyl)))] (TFB) and a cross-linkable small molecule, 4,4'-bis(3-vinyl-9H-carbazol-9-yl)1,1'-biphenyl (CBP-V), to facilitate selective carrier transport between the thin perovskite layer and the organic photoactive layer. By employing this strategy, we have successfully developed near-infrared NPDs with a responsivity of 0.49 A/W, a maximum external quantum efficiency reaching up to 72.41%, a full width at half-maximum (fwhm) of less than 100 nm, and an impressive specific detectivity of 6.74 × 10¹² Jones. This innovative methodology not only alleviates the fabrication complexities associated with thick-film perovskites but also paves the way for the preparation of high-performance near-infrared NPDs. Additionally, these detectors show substantial promise in photoplethysmography (PPG) applications, enabling real-time, noninvasive heart rate monitoring with enhanced accuracy and reliability.