Sensitive photodetection below silicon bandgap using quinoid-capped organic semiconductors.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 36989368.
- Also identified by DOI 10.1126/sciadv.adf6152 and PMC identifier 10058242.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
High-sensitivity organic photodetectors (OPDs) with strong near-infrared (NIR) photoresponse have attracted enormous attention due to potential applications in emerging technologies. However, few organic semiconductors have been reported with photoelectric response beyond ~1.1 μm, the detection limit of silicon detectors. Here, we extend the absorption of organic small-molecule semiconductors to below silicon bandgap, and even to 0.77 eV, through introducing the newly designed quinoid-terminals with high Mulliken-electronegativity (5.62 eV). The fabricated photodiode-type NIR OPDs exhibit detectivity (<i>D</i><sup>*</sup>) over 10<sup>12</sup> Jones in 0.41 to 1.2 μm under zero bias with a maximum of 2.9 × 10<sup>12</sup> Jones at 1.02 μm, which is the highest <i>D</i><sup>*</sup> for reported OPDs in photovoltaic-mode with response spectra beyond 1.1 μm. The high <i>D</i><sup>*</sup> in 0.9 to 1.2 μm is comparable to those of commercial InGaAs photodetectors, despite the detection limit of our OPDs is shorter than InGaAs (~1.7 μm). A spectrometer prototype with a wide measurable region (0.4 to 1.25 μm) and NIR imaging under 1.2-μm illumination are demonstrated successfully in OPDs.