Ultraviolet Photodetectors With Narrow-Band Spectral Response Using TAPC Donor

Zhu, Lu; Wang, W. S.; Yao, Zong-jian; Zhang, X. Q.; Wang, Yue‐Sheng

doi:10.1109/ted.2012.2219864

Cited by 11 publications

(9 citation statements)

References 21 publications

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“…The higher on/off ratio at the beginning is due to the ultralow dark current density of 5.48 × 10 −11 A.cm −2 . After reaching the saturation stage, although the dark current density increases to 1.66 × 10 −10 A.cm −2 , the value is still three orders of magnitude lower than previously reported UV OPDs . With the very stable and enhanced photocurrent as shown in Figure , the stable on/off ratio of 1.7 × 10 5 has been achieved.…”

Section: Resultsmentioning

confidence: 62%

“…The on/off ratio at a given illumination intensity can be examined to compare different PDs sensitivities . In this work, the high on/off ratio of 10 5 is two orders of magnitude larger than previously reported UV OPDs operated at a large reverse bias, and emerging inorganic nanostructured UV PDs . The physical origin of such high on/off ratio of TiO 2 based OPDs will be discussed in the next section in detail.…”

Section: Resultsmentioning

confidence: 82%

“…Stability is of importance for the practical applications of UV OPDs. However, this issue has not commonly studied to date in the most of the reported UV OPDs . One report stated that UV OPDs with m‐MTDATA donor could keep 67% of the maximum photocurrent after continuous UV illumination up to roughly 1000 minutes .…”

Section: Resultsmentioning

confidence: 99%

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Photovoltaic Mode Ultraviolet Organic Photodetectors with High On/Off Ratio and Fast Response

Zhu

Choy

Sha

et al. 2014

Advanced Optical Materials

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nanoparticles have been adopted to fabricate light-detection devices, which demonstrate ultrahigh photocurrent gain, nonetheless, these devices are accompanied by high operation voltage, low on/off ratio, and slow response time. [ 9 ] Different from conventional inorganic UV PDs, UV PDs utilizing organic semiconductors with fl exible bandgap engineering, less restricted substrates, and simple fabrication offer a promising pathway for low-cost, large-area, and fl exible UV PDs. [ 10 ] The majority of previously reported UV organic PDs (OPDs) achieved high effi ciency comparable with inorganic counterparts. Although some OPDs had external quantum effi ciency (EQE) over unity, a large dark current density was obtained simultaneously. Hence, low on/off ratio near or less than 10 3 was observed when these OPDs were operated at a monochromatic light with the wavelength of 365 nm and intensity of about 1 mW.cm −2 . [ 4,[11][12][13] For example, hybrid planar-bulk-heterojunction UV OPDs consisted of 4,4′,4′′-tri-(2-methylphenyl phenylamino) triphenylaine (m-MTDATA)/m-MTDATA:aluminum (III) bis(2-methyl-8-quinolinato)4-phenylphenolate (BAlq)/BAlq were demonstrated with a high EQE of 175% at a reverse voltage of 7 V, whereas the on/off ratio was approximately 1.9 × 10 3 when the intensity of 365 nm incident light was about 1.2 mW.cm −2 . [ 11 ] Bilayer UV OPDs of poly(9,9-dihexylfl uorene-2,2-diyl) (PFH)/a silane-containing triazine derivative (NSN) with a high responsivity of 0.696 A/W (corresponding EQE is 236.5%) at a large voltage of -12 V were reported that the on/off ratio was about 5 × 10 2 when the devices were illuminated by a monochromatic light of 365 nm with an intensity of 1 mW.cm −2 . [ 13 ] These high-effi ciency UV OPDs are operated at a large reverse voltage, which can effectively increase electric fi eld within OPDs, reduce the probability of excitons recombination and raise the effi ciency of excitons dissociation, thereby boosting EQE. [ 14,15 ] Nevertheless, large dark current due to the large reverse bias will also be obtained. Electron/hole blocking layers have been proposed to suppress dark current in OPDs and nanocrystal infrared PDs, dark current still remained 10 −6 to 10 −7 A/cm 2 when these devices were operated at a large reverse bias. [ 16 ] Up to now, photovoltaic mode (i.e., self-powered or zerobias operation mode) PDs were mainly reported in inorganic PDs, [ 15,17 ] but not systematically investigated in UV OPDs. Ultraviolet (UV) organic photodetectors (OPDs) operated in the photovoltaic mode, achieving a very high on/off ratio of 10 5 and a fast response time of 20 ns (a decay time of 888 ns), are demonstrated in this work. Light-induced tuning of the barrier height at the two interfaces of the carrier-extraction layer and light-induced tuning of series resistance are proposed to obtain the high on/off ratio. Fast response of the device is demonstrated through the ultrafast trap fi lling process. The high on/off ratio and fast response are simultaneously realized by introducing TiO 2 n...

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Section: Resultsmentioning

confidence: 62%

Section: Resultsmentioning

confidence: 82%

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Photovoltaic Mode Ultraviolet Organic Photodetectors with High On/Off Ratio and Fast Response

Zhu

Choy

Sha

et al. 2014

Advanced Optical Materials

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“…Wang et al attempted to construct organic narrowband UV PDs (peaked at 330 nm) using TAPC as the donor. 22 The fabricated device showed a narrow response bandwidth of 30 nm (316–346 nm). The obtained narrowband response was ascribed to the blocking effect of ITO for shorter wavelengths and the absorption of organic materials for longer wavelengths.…”

Section: Introductionmentioning

confidence: 98%

A porous GaN/MoO₃ heterojunction for filter-free, ultra-narrowband ultraviolet photodetection

et al. 2022

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“…New generations of semiconductors such as organics, perovskites and inorganic nanocrystals with tailorable optical properties have been proposed as one solution to achieve wavelength sensitivity since the spectral nature of their optical absorptions can be manipulated and indeed designed by molecular level engineering and/or altering quantum confinement . However, achieving adequate responsivities in a particular narrow color window whilst ensuring darkness outside that window has proven challenging, if not impossible.…”

Section: Introductionmentioning

confidence: 99%

Cavity Enhanced Organic Photodiodes with Charge Collection Narrowing

Yazmaciyan

Meredith

Armin

2019

Advanced Optical Materials

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Color discrimination in photodetection is conventionally achieved using broadband‐absorbing inorganic semiconductors with passive optical filters. Organic semiconductors show promise to deliver narrowband spectral responses due to their tunable optical properties. While achieving narrow‐absorbing organic semiconductors is an ongoing endeavor in the synthetic chemistry community, charge collection narrowing is introduced as a “material‐agnostic” technique to realize narrowband spectral responses using broadband absorbers such as blends of organic semiconductors, inorganic nanocrystals, and perovskites in a photodiode architecture. Charge collection narrowing in organic semiconductors demands photoactive junction thicknesses on the order of a few micrometers causing fabrication difficulties and limitations in device metrics such as frequency bandwidth. In this work it is shown that electrical inversion can result in charge collection narrowing in organic photodiodes with active layer thicknesses on the order of hundreds of nanometers and hence much easier to achieve via high throughput solution processing techniques. Additionally, it is shown that an indium tin oxide/gold electrode with modified work function acts as a cavity mirror, further narrowing the spectral response and at the same time delivering an extremely selective cathode, suppressing the dark current dramatically. Nearly voltage independent detectivities of 1013 Jones are achieved with an active sensing area of 0.2 cm2.

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Ultraviolet Photodetectors With Narrow-Band Spectral Response Using TAPC Donor

Cited by 11 publications

References 21 publications

Photovoltaic Mode Ultraviolet Organic Photodetectors with High On/Off Ratio and Fast Response

Photovoltaic Mode Ultraviolet Organic Photodetectors with High On/Off Ratio and Fast Response

A porous GaN/MoO₃ heterojunction for filter-free, ultra-narrowband ultraviolet photodetection

Cavity Enhanced Organic Photodiodes with Charge Collection Narrowing

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Ultraviolet Photodetectors With Narrow-Band Spectral Response Using TAPC Donor

Cited by 11 publications

References 21 publications

Photovoltaic Mode Ultraviolet Organic Photodetectors with High On/Off Ratio and Fast Response

Photovoltaic Mode Ultraviolet Organic Photodetectors with High On/Off Ratio and Fast Response

A porous GaN/MoO3 heterojunction for filter-free, ultra-narrowband ultraviolet photodetection

Cavity Enhanced Organic Photodiodes with Charge Collection Narrowing

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Product

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A porous GaN/MoO₃ heterojunction for filter-free, ultra-narrowband ultraviolet photodetection