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

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 lowtemperature 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 halfmaximum of 16 nm. Combined with a low dark current, a high specific detectivity of 8.45 × 10 12 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.

Self‐Polarized BaTiO3 for Greatly Enhanced Performance of ZnO UV Photodetector by Regulating the Distribution of Electron Concentration

“…However, the practical applications of ZnO film UV PDs have been seriously hindered from their low on/off ratio (≈10) or long decay time (≈20 s) due to the influence of adsorption and desorption of surface oxygen molecules . A variety of methods have been reported for improving the performance of ZnO devices including surface plasma modification, internal doping, heterojunction, and surface functionalization . Ouyang et al integrated ZnO film UV PDs with CdMoO 4 microplates.…”

Ultrahigh Responsivity UV Photodetector Based on Cu Nanostructure/ZnO QD Hybrid Architectures

“…Consequently, the PD2 exhibited an outstanding performance among Cu NS/ZnO QD hybrid architecture photodetectors under an identical condition, and an excellent reproducibility and stability was also witnessed with the photodetectors within 50 cycles and 7 d as shown in Figure S12 (Supporting Information). Meanwhile, many efforts have been endeavored to boost the performance of ZnO photodetectors [33][34][35][52][53][54][55][56][57][58][59][60][61] as summarized in Table 5, and obviously, the performance of the PD2 was predominantly superior to the ZnO photodetectors. Specifically, various nanocomposites were adapted to ZnO NSs based UV photodetectors: ZnO NWs/ graphene foams can guarantee a high I on of ≈1 mA, [57] and ZnS/ZnO heterostructures exhibited a relatively high R of 94.5 A W −1 .…”

“…Ultraporous ZnO NPs networks [33] 370 nm, 40 µW cm −2 5 512 ≈1.3 × 10 4 ≈250 ≈150 -Se/ZnO [55] 370 nm, 0.85 mW cm −2 0 ≈0.006 2.65 6.9 × 10 −4 0.0135 -F8T2/ZnO nanocomposites [56] 358 nm, 24.6 µW cm −2 3 ≈5 2.24 × 10 3 --782…”

Highly sensitive, sub-microsecond polymer photodetectors for blood oxygen saturation testing

“…The surface and interface in PM-PPDs can be considered as an optical switch to control current density in dark and light illumination conditions. It should be highlighted that the active layers have one type charge carrier (electron or hole) transport channels and large amounts of isolated another charge carrier traps, leading to dark current density (J d ) as low as possible [7][8][9][10][11]. Considerable achievements on PM-PPDs have been obtained in terms of tunable spectral response and optimal EQE values by employing ternary strategy, thick active layers, molecular engineering and interfacial engineering [12][13][14][15][16][17][18].…”