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Narrowband Ultraviolet Photodetectors Based on Nanocomposite Thin Films With High Gain and Low Driving Voltage

Erjin Zheng, Xiaoyu Zhang, Monica R Esopi, Chen Cai, Beiying Zhou, Yi-Yu Lin, Qiuming Yu

ACS Appl Mater Interfaces. 2018 Dec 5;10(48):41552-41561.

PMID: 30383357

Abstract:

Narrowband ultraviolet (UV) photodetectors are highly desired in multiple areas. Photodetectors based on organic-inorganic nanocomposites offer high sensitivity, widely adjustable response range, light weight, and low-temperature solution processibility. However, the broad absorption range of organic and inorganic semiconductor materials makes it difficult to achieve a narrowband detection feature for nanocomposite photodetectors. In this work, nanocomposite thin films containing the wide band gap conjugated polymer poly[(9,9-dioctylfluorenyl-2,7-diyl)- alt- co-(bithiophene)] (F8T2) blended with wide band gap ZnO nanoparticles (NPs) serve as the active layers of the photodetectors. Narrowband UV photodetectors with high gain and low driving voltage are demonstrated by adopting a symmetric device structure, controlling the active layer composition and microstructure, and manipulating the light penetration depth in the active layer. The fabricated photodetector exhibits a high external quantum efficiency of 782% at 358 nm under a low forward bias of 3 V with the full-width at half-maximum of 16 nm. Combined with a low dark current, a high specific detectivity of 8.45 × 1012 Jones is achieved. The impacts of the F8T2:ZnO NPs weight ratio and the device structure on the UV-selectivity and the device performance are investigated and discussed. Our method offers a pathway to design and fabricate narrowband UV photodetectors.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
AP210347561 F8T2 F8T2 210347-56-1 Price
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