Solution-processed upconversion photodetectors based on quantum dots

Zhou, Wenjia; Shang, Yuequn; Arquer, F. Pelayo Garcı́a de; Xu, Kaimin; Wang, Ruili; Luo, Shaobo; Xiao, Xiongbin; Zhou, Xiaoshu; Huang, Ruimin; Sargent, Edward H.; Ning, Zhijun

doi:10.1038/s41928-020-0388-x

Cited by 181 publications

(182 citation statements)

References 48 publications

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“…Prior work on upconversion imagers utilized III–V compound semiconductors within the photo‐sensing layers, [ 9,10 ] but the fast lateral charge diffusion inherent to these materials results in poor image resolution. Solution‐processable materials such as colloidal quantum dots (CQD) [ 11,12 ] and organic semiconductors [ 13–19 ] have improved spatial resolution by virtue of their lower lateral conductivity. Consequently, this work examines solution‐processable polymers [ 20–28 ] for infrared sensing, leveraging their amorphous nature to form smooth thin films that result in high quality and uniform optical emission.…”

Section: Figurementioning

confidence: 99%

Organic Upconversion Imager with Dual Electronic and Optical Readouts for Shortwave Infrared Light Detection

Eedugurala

Leem

et al. 2021

Adv Funct Materials

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There remains a critical need for large‐area imaging technologies that operate in the shortwave infrared spectral region. Upconversion imagers that combine photo‐sensing and display in a compact structure are attractive since they avoid the costly and complex process of pixilation. However, upconversion device research is primarily focused on the optical output, while electronic signals from the imager remain underutilized. Here, an organic upconversion imager that is efficient in both optical and electronic readouts, extending the capability of human and machine vision to 1400 nm, is designed and demonstrated. The imager structure incorporates interfacial layers to suppress non‐radiative recombination and provide enhanced optical upconversion efficiency and electronic detectivity. The photoresponse is comparable to state‐of‐the‐art organic infrared photodiodes exhibiting a high external quantum efficiency of ≤35% at a low bias of ≤3 V and 3 dB bandwidth of 10 kHz. The large active area of 2 cm2 enables demonstrations such as object inspection, imaging through smog, and concurrent recording of blood vessel location and blood flow pulses. These examples showcase the potential of the authors’ dual‐readout imager to directly upconvert infrared light for human visual perception and simultaneously yield electronic signals for automated monitoring applications.

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Section: Figurementioning

confidence: 99%

Organic Upconversion Imager with Dual Electronic and Optical Readouts for Shortwave Infrared Light Detection

Eedugurala

Leem

et al. 2021

Adv Funct Materials

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Section: Phototransistorsmentioning

confidence: 99%

“…Upconversion devices can convert the invisible IR into visible light without ROICs and have made significant progress in recent years. [70,[89][90][91][92] This section will discuss the progress of scalable application of CQD based IR photodetectors in details.…”

Section: Scalable Device Structure Of Cqd Ir Photodetectorsmentioning

confidence: 99%

“…Instead of adding Ag atoms into electron blocking layer, they added a certain amount of Ag NPs into ZnO layer (electron transport layer). [ 70 ] The Ag NPs in ZnO layer would trap electrons under illumination, and induce ZnO layer energy band bending (Figure 8d,e). The holes could inject into CQD layer by tunneling effect giving rise to the increase of gain.…”

Section: Device Structure Engineeringmentioning

confidence: 99%

“…recently reported a two terminal upconversion photodetector based on CQDs that was fabricated by solution process, which would save the fabrication cost and induce low working voltage (Figure 13c). [ 70 ] PbS CQDs (300–1600 nm) were used as IR absorption layer of the photodetector and luminance CdSe/ZnS CQDs were adopted as light emitting layer. Due to the high gain of the IR detector part (The mechanism of IR photodetector is discussed in Chapter 4.2.…”

Section: Scalable Device Structure Of Cqd Ir Photodetectorsmentioning

confidence: 99%

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Integrated Structure and Device Engineering for High Performance and Scalable Quantum Dot Infrared Photodetectors

Zhou

Ning

2020

Small

Self Cite

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Colloidal quantum dots (CQDs) are emerging as promising materials for the next generation infrared (IR) photodetectors, due to their easy solution processing, low cost manufacturing, size‐tunable optoelectronic properties, and flexibility. Tremendous efforts including material engineering and device structure manipulation have been made to improve the performance of the photodetectors based on CQDs. In recent years, benefiting from the facial integration with materials such as 2D structure, perovskite and silicon, as well as device engineering, the performance of CQD IR photodetectors have been developing rapidly. On the other hand, to prompt the application of CQD IR photodetectors, scalable device structures that are compatible with commercial systems are developed. Herein, recent advances of CQD based IR photodetectors are summarized, especially material integration, device engineering, and scalable device structures.

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Self‐Powered Organic Photodetectors with High Detectivity for Near Infrared Light Detection Enabled by Dark Current Reduction

Wei

Chen

Liu

et al. 2021

Adv Funct Materials

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Organic photodetectors (OPDs) for near infrared (NIR) light detection represents cutting‐edge technology for optical communication, environmental monitoring, biomedical imaging, and sensing. Herein, a series of self‐powered OPDs with high detectivity are constructed by the sequential deposition (SD) method. The dark currents (Jd) of SD devices are effectively reduced in comparison to blend casting (BC) ones due to the vertical phase segregation structure. Impressively, the Jd values of SD devices based on D18 and Y6 system is reduced to be 2.1 × 10−11 A cm−2 at 0 V, which is two orders of magnitude lower than those of the BC devices. The D* value of the SD device is superior to that of BC device under different bias voltages (0, −0.5, −1.0, and −2.0 V) due to the reduction of dark current, which originates from the fine vertical phase separation structure of the SD device. The mechanism studies shows that the vertical phase segregation structure can effectively suppress the unfavorable charge injection, thus reducing the dark current. Also, the surface energy is proven to play a key role in the photocurrent stability. In addition, the flexible OPDs demonstrate excellent performance in photoplethysmography test.

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Solution-processed upconversion photodetectors based on quantum dots

Cited by 181 publications

References 48 publications

Organic Upconversion Imager with Dual Electronic and Optical Readouts for Shortwave Infrared Light Detection

Organic Upconversion Imager with Dual Electronic and Optical Readouts for Shortwave Infrared Light Detection

Integrated Structure and Device Engineering for High Performance and Scalable Quantum Dot Infrared Photodetectors

Self‐Powered Organic Photodetectors with High Detectivity for Near Infrared Light Detection Enabled by Dark Current Reduction

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