Solution-processed image sensors on flexible substrates

Pierre, Adrien; Arias, Ana Claudia

doi:10.1088/2058-8585/1/4/043001

Cited by 46 publications

(41 citation statements)

References 110 publications

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“…[ 35,36 ] The broad LDR is particularly important for image sensors, which means that the device can operate over a broad light intensity range. [ 37 ] The spectral responsivity ( R ) and specific detectivity ( D *) are other two key figure‐of‐merit parameters of photodetectors. The R and D * are expressed as: [ 38 ]

R = \frac{J_{ph} – J_{dark}}{L_{light}}

D^{*} = \frac{{(A f)}^{0.5}}{(i_{n} / R)}

where A, f , and i n are the effective area of the device, the electrical bandwidth, and the noise current, respectively.…”

Section: Figurementioning

confidence: 99%

A Microchannel‐Confined Crystallization Strategy Enables Blade Coating of Perovskite Single Crystal Arrays for Device Integration

Deng

Jie

et al. 2020

Advanced Materials

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to millimeter scale, which is much larger than the carrier diffuse length in PSCs and thus greatly hinders their device applications. To solve this problem, a space-confined strategy was introduced into these methods to grow PSCs with thickness from several hundreds of nanometers to a few micrometers. [14,17−19] However, the lateral dimension of the resulting PSCs was limited by lack of solution supplement at the confined areas to provide enough solutes for continuous crystal growth. Moreover, the reported growth techniques for PSCs are quite time consuming and batch processes with limited throughput.Among various solution-based methods, blade coating has the advantages of high throughput, roll-to-roll compatibility, and minimal material wastage. [20−22] Although it has been widely applied to fabricate perovskite thin films for device applications, [23−26] PSCs deposited by the blade coating method generally exhibit a nonuniform morphology with low crystallinity, making them very challenging to fabricate high-performance integrated devices. The solution fluidic flow instabilities are believed to be the primary cause. [25,27] During the coating process, perovskite solutes would be turbulently transported to various locations of meniscus front, and this yields perovskite supersaturated phase containing randomly aggregated solutes, resulting in inhomogeneous nucleation and formation of the nonuniform and misaligned seed crystals. Therefore, it still remains a great challenge to achieve large-area growth of PSCs with highly uniform morphology via blade coating.Herein, we report the development, for the first time, of a microchannel-confined crystallization (MCC) strategy for the large-area growth of highly aligned PSCs with uniform morphology, which is applicable to device integration. The microchannels not only helped stabilize the transport of perovskite solutes but also reduced the density of nucleation events, ensuring the formation of uniform and continuous PSCs arrays in the channels. Both in situ experimental observation and theoretical simulation verified the vital roles of the microchannel in controlling the solution flow dynamics. The resulting PSCs possess a long carrier lifetime of 175 ns and an ultralow defect density of 2 × 10 9 cm −3 , which are comparable to the corresponding Perovskite single crystals (PSCs) possess superior optoelectronic properties compared to their corresponding polycrystalline films, but their applications of PSCs in high-performance, integrated devices are hindered by their heavy thickness and difficulty in scalable deposition. Here, a microchannel-confined crystallization (MCC) strategy to grow uniform and large-area PSC arrays for integrated device applications is reported. Benefiting from the confinement effect of the microchannels, solution flow dynamics is well controlled, and thus uniform deposition of PSC arrays with suitable thickness is achieved, meaning they are applicable for scale-up device applications. The resulting PSCs possess excellent optoelectronic proper...

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R = \frac{J_{ph} – J_{dark}}{L_{light}}

D^{*} = \frac{{(A f)}^{0.5}}{(i_{n} / R)}

where A, f , and i n are the effective area of the device, the electrical bandwidth, and the noise current, respectively.…”

Section: Figurementioning

confidence: 99%

A Microchannel‐Confined Crystallization Strategy Enables Blade Coating of Perovskite Single Crystal Arrays for Device Integration

Deng

Jie

et al. 2020

Advanced Materials

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“…Comparing pressure signals from arterial pulses and electrocardiograms (ECGs) enable extraction of pulse transit times to determine the systolic blood pressure . Alternatively, the blood flow motion during heart beats can be monitored indirectly in photoplethysmograms (PPGs) which use flexible photodetector technologies . Notably, a complete epidermal system that allows wireless, battery‐free, continuous sensing of PPGs and ECGs on neonates has been achieved with performance comparable to clinical‐grade monitoring systems (Figure b) .…”

Section: Applications Of Pressure Sensors In Monitoring Body Motionmentioning

confidence: 99%

Flexible Pressure Sensors for Objective Assessment of Motor Disorders

Amit

Chukoskie

Skalsky

et al. 2019

Adv Funct Materials

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Monitoring body motion is relevant to motor control disorders as well as assessment of fine motor skills in child development. Furthermore, motion tracking is necessary for rehabilitation monitoring and injury prevention and benefits both sick and healthy individuals. Flexible pressure sensors based on resistors, capacitors, inductors, or transistors are reviewed in the context of healthcare measurements, ranging from physiological signals to body movement characteristics such as grip and gait. To demonstrate the use of flexible pressure sensors for motor assessment, a touch sensing glove that evaluates fine motor skills in autism research is developed. The results show that autistic children perform fewer taps per minute compared to typically developing children, with larger variations in tap durations. In a second example, a force and motion sensing glove is developed to assess spasticity, a neuromuscular disorder that causes muscle stiffness/resistance and jerky movement. Analyses of force versus velocity show movement-dependent muscle resistance in a patient with spasticity. Through these flexible sensor systems, the shift from subjective scores to objective measurement will promote better diagnosis and dramatically improve the accuracy in tracking patient response to therapy.patients doing certain movements, and then clinicians rank each patient's level according to qualitative descriptions in benchmark classification scales. [12,13] The subjective scores can be inconsistent between raters and do not capture finelevel changes in a patient's progress in response to therapy. Therefore, there is a critical need to tackle the issue of imprecise assessment of motor disorders.With recent advances in flexible sensors and innovations in tactile sensing, [14][15][16][17][18][19] we have new low-cost technologies that are prime to facilitate quantitative evaluation of motor control. This progress report presents current developments in wearable sensor systems applicable to motor disorders, so that consistent, objective metrics become available to accurately track whether a treatment effectively relieves symptoms. The wearable sensors are not limited to placement on patients but can also be worn by clinicians or caregivers to assist them in taking measurements during patient interactions. [20,21] The point-of-care sensor systems will allow frequent monitoring, which is highly desirable to offer a better understanding of the patient's short and long-term response to therapies, to tailor treatment and improve outcome and quality of life for patients.Other reviews [14][15][16][17][18][19] have already extensively covered the flexible materials and devices used in tracking vital signs and electronic skin applications. In light of that, this progress report focuses on the applications in monitoring motor skills, in particular to implement pressure sensor designs for wearable systems with diverse form factors, for instance, gloves, [20,22,23] epidermal tags tags, [24,25] and shoe insoles. [26,27] We will discuss the mechanis...

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“…[1][2][3][4][5][6][7][8][9][10][11][12][13] Especially, optical imaging is important for proximity sensing, [14] sensing of activities of blood vessels, [15] body skeleton diagnosis using X-rays, [16,17] and retinal reconstruction. [16,17,[31][32][33][34][35] With advances of these transistors, organic image sensors with a large numbers of pixels (e.g., 256 × 256) have been demonstrated. [21][22][23][24][25][26][27][28][29][30] To realize a multiplexing signal readout for organic photodiodes, transistors-which are three-terminal devices-have been commonly used.…”

Section: Doi: 101002/aelm201800311mentioning

confidence: 99%

Low‐Power Monolithically Stacked Organic Photodiode‐Blocking Diode Imager by Turn‐On Voltage Engineering

Matsuhisa

Zalar

et al. 2018

Adv Elect Materials

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Multiplexing the signal readout from the organic photodetector matrix is essential for high‐resolution and large‐area imaging applications. This endeavor can be realized by pixels containing photodiodes and switching elements, such as transistors or blocking diodes. The use of blocking diodes is beneficial for simpler fabrication and fewer wires than transistors. However, imagers with blocking diodes can always require additional voltage to turn off the unselected lines, which causes high standby power and increased complexity of the readout circuit. In this study, low standby power organic imagers are realized that are suitable for wearable optical imaging applications in which resources for power and readout circuits are limited. Pixels with a vertical stack of organic photodiodes and blocking diode layers are investigated. By increasing the built‐in potential of blocking diodes, the turn‐on voltage of the monolithically stacked photodiode‐blocking diode device can be adjusted to enable its turn‐off at 0 V. This leads to a three‐orders‐of‐magnitude reduction of the current of pixels at 0 V. With these pixels, imagers based on organic photodiode‐blocking diode stack devices are demonstrated with improved image quality and substantially reduced crosstalk current, while operating at zero standby power.

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Solution-processed image sensors on flexible substrates

Abstract: Copper(I) thiocyanate (CuSCN) as a hole-transport material for large-area opto/electronics

Cited by 46 publications

References 110 publications

A Microchannel‐Confined Crystallization Strategy Enables Blade Coating of Perovskite Single Crystal Arrays for Device Integration

A Microchannel‐Confined Crystallization Strategy Enables Blade Coating of Perovskite Single Crystal Arrays for Device Integration

Flexible Pressure Sensors for Objective Assessment of Motor Disorders

Low‐Power Monolithically Stacked Organic Photodiode‐Blocking Diode Imager by Turn‐On Voltage Engineering

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