“…§ is strongly dependent on optical power. || D is reported as being one of the donors also explored by Bulliard et al [120]. ¶ while the peak wavelength is out of the spectral range taken here as red, the photoresponse of this particular implementation is predominantly in the red.…”
“…These values are fully compatible with applications such as colour imaging for consumer electronic devices, as well as more demanding applications, e.g., computer vision. Particularly successful implementations have relied on dedicated molecular design strategies, e.g., D-A molecules approaching the cyanine limit (FWHM EQE ≈90-100 nm) [120,126]. Additionally, two important schemes relating to aggregation effects in the solid state have emerged as highly effective for achieving NBA-type photodetection with EQE widths well below 100 nm.…”
Section: Impact Of Narrowband Strategiesmentioning
confidence: 99%
“…Chloroboron subphthalocyanine (SubPc) is another small molecule that has delivered high phototransduction efficiency in a number of works, giving an EQE p of 62.6% in combination with DCV3T [58], and 60.1% in combination with quinacridone [58,61] (figure 7(b)). Newly synthesised small-molecule donors featuring a D-A structure approaching the cyanine limit have also yielded EQE values in the ≈50%-70% range in combination with fullerenes ( figure 7(b)) [120,126,128,129]. Finally, Li et al demonstrated the potential of a singlecomponent squaraine photoactive layer, achieving an EQE p as high as 66% [72].…”
“…A considerable number of NBA-type devices feature a FWHM EQE greater than 100 nm. A recurrent feature of many of them is the use of fullerenes, which generally broaden the spectral width and/or reduce the spectral rejection ratio (e.g., with respect to the blue, see figure 7(b)) [120,125,126,128,129]. A number of fullerene-free strategies have thus been considered to overcome this challenge and achieve FWHM EQE values around or below 100 nm.…”
The capability of detecting visible and near infrared light within a narrow wavelength range is in high demand for numerous emerging application areas, including wearable electronics, the Internet of Things, computer vision, artificial vision and biosensing. Organic and perovskite semiconductors possess a set of properties that make them particularly suitable for narrowband photodetection. This has led to rising interest in their use towards such functionality, and has driven remarkable progress in recent years. Through a comparative analysis across an extensive body of literature, this review provides an up-to-date assessment of this rapidly growing research area. The transversal approach adopted here focuses on the identification of: (a) the unifying aspects underlying organic and perovskite narrowband photodetection in the visible and in the near infrared range; and (b) the trends relevant to photoconversion efficiency and spectral width in relation to material, device and processing strategies. A cross-sectional view of organic and perovskite narrowband photodetection is thus delineated, giving fresh insight into the status and prospects of this research area.
“…§ is strongly dependent on optical power. || D is reported as being one of the donors also explored by Bulliard et al [120]. ¶ while the peak wavelength is out of the spectral range taken here as red, the photoresponse of this particular implementation is predominantly in the red.…”
“…These values are fully compatible with applications such as colour imaging for consumer electronic devices, as well as more demanding applications, e.g., computer vision. Particularly successful implementations have relied on dedicated molecular design strategies, e.g., D-A molecules approaching the cyanine limit (FWHM EQE ≈90-100 nm) [120,126]. Additionally, two important schemes relating to aggregation effects in the solid state have emerged as highly effective for achieving NBA-type photodetection with EQE widths well below 100 nm.…”
Section: Impact Of Narrowband Strategiesmentioning
confidence: 99%
“…Chloroboron subphthalocyanine (SubPc) is another small molecule that has delivered high phototransduction efficiency in a number of works, giving an EQE p of 62.6% in combination with DCV3T [58], and 60.1% in combination with quinacridone [58,61] (figure 7(b)). Newly synthesised small-molecule donors featuring a D-A structure approaching the cyanine limit have also yielded EQE values in the ≈50%-70% range in combination with fullerenes ( figure 7(b)) [120,126,128,129]. Finally, Li et al demonstrated the potential of a singlecomponent squaraine photoactive layer, achieving an EQE p as high as 66% [72].…”
“…A considerable number of NBA-type devices feature a FWHM EQE greater than 100 nm. A recurrent feature of many of them is the use of fullerenes, which generally broaden the spectral width and/or reduce the spectral rejection ratio (e.g., with respect to the blue, see figure 7(b)) [120,125,126,128,129]. A number of fullerene-free strategies have thus been considered to overcome this challenge and achieve FWHM EQE values around or below 100 nm.…”
The capability of detecting visible and near infrared light within a narrow wavelength range is in high demand for numerous emerging application areas, including wearable electronics, the Internet of Things, computer vision, artificial vision and biosensing. Organic and perovskite semiconductors possess a set of properties that make them particularly suitable for narrowband photodetection. This has led to rising interest in their use towards such functionality, and has driven remarkable progress in recent years. Through a comparative analysis across an extensive body of literature, this review provides an up-to-date assessment of this rapidly growing research area. The transversal approach adopted here focuses on the identification of: (a) the unifying aspects underlying organic and perovskite narrowband photodetection in the visible and in the near infrared range; and (b) the trends relevant to photoconversion efficiency and spectral width in relation to material, device and processing strategies. A cross-sectional view of organic and perovskite narrowband photodetection is thus delineated, giving fresh insight into the status and prospects of this research area.
“…1(b) and it have a LUMO and HOMO values as a 3.6 eV and 5.5 eV as shown in Fig. 1(c)
20 respectively.Figure 1( a ) Structure of the OPD device with and without SiOxNy buffer layer. ( b ) Chemical structure of blend organic film ( c ) HOMO and LUMO energy values of blend organic film.
…”
An advanced organic photodetector (OPD) with a butter layer of Si-rich silicon oxynitride (SiO x N y ) was fabricated. The detector structure is as follows: Indium tin oxide (ITO) coated glass substrate/ SiO x N y (10 nm)/naphthalene-based donor:C60(1:1)/ITO. Values of x and y in SiO x N y were carefully controlled and the detector performances such as dark current and thermal stability were investigated. When the values of x and y are 0.16 and 0.66, the detector illustrates low dark current as well as excellent thermal stability. In the OPD, silicon oxynitride layer works as electron barrier under reverse bias, leading to the decrease of dark current and increase of detectivity. Since the band gap of silicon oxynitride unlike conventional buffer layers can also be controlled by adjusting x and y values, it can be adapted into various photodiode applications.Organic photodetectors (OPDs) have been widely used in practical applications such as photo-sensors, chemical sensors 1-6 , X-ray detectors 7 , and image sensors [8][9][10][11] . Among the applications, image sensors, which have been considered of replacing conventional silicon-based image sensors 4, 10 , have attracted research interest from industries and there has been considerable effort to improve the device performances of them such as the spectral response, external quantum efficiency (EQE), dark current (DC), and sensitivity. Among these, the External quantum efficiency (EQE), DC, and thermal stability are the key factors to evaluate the performance of OPDs. EQE is coupled to the efficiency and signal-to-noise ratio (SNR) of the devices. Low DC stabilizes the signal of the devices, leading to high SNR. Because organic materials in OPDs are exposed to high temperature process such as post-annealing at 180 °C, passivation step, top layer planarization, and microlens forming process, they should be thermally stable without performance degradation.Decreasing DC and enhancing thermal stability have been generally improved by introducing new buffer layers 12 such as MoO x 13 , WO x 14 , and VO x 15 . However, MoO x is susceptible to the loss of oxygen during evaporation which can result in the change of stoichiometry and electronic energy levels 16 . Since various active materials are also used in fabricating OPDs, the band structure of a buffer layer should be aligned to HOMO and LUMO levels of bulk heterojuction (BHJ) films. Conventional buffer layers such as MoO x are very difficult to change their band structure, i.e. their HOMO and LUMO levels do not change without regard to neighboring active materials. Therefore, new buffer layers with thermal stability and easily adjustable band structure have been required.As one of good candidates for new buffer layers, silicon oxynitride (SiO x N y ) film has been well received because its band structure is able to be freely controlled by adjusting the x and y. Moreover, it is thermally stable at high temperature process and is also chemically inert enough to be used in electronic devices 17 such as thin-film tr...
Spectroscopic sensing combined with optical imaging is crucial with respect to today's ever‐growing demand for instant analytical techniques to be incorporated in various handheld and wearable devices. Further miniaturization and integration of such types of sensors is critical and wavelength‐selective organic photodetectors (OPDs) may provide the required technology. In this progress report, some early OPD applications and their potential are presented. Crucial device parameters such as the specific detectivity, external quantum efficiency, and dark current density of visible and near‐infrared wavelength‐selective photodetectors are compared and assayed to theoretical and semi‐empirical limits. The different organic detector approaches include the use of inherently narrow‐band absorbers as well as internally filtered and microcavity devices. Each of these strategies comes with its own specific material and device design criteria, around which material development and selection should be centered to move beyond the current state of the art. As OPD technology matures, device stability becomes important and is hence also briefly discussed. Via this perspective, it is aimed to provide the reader with critical insights into the device physics and chemistry of wavelength‐selective OPDs, hereby providing leverage for new ideas to bring this technology to the market.
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