Search query: Ultrasensitive solution-cast quantum dot photodetector

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abstract: Solution processed electronic and optoelectronic devices offer low cost, large device area, physical flexibility and convenient materials integration compared to conventional epitaxially grown, lattice matched, crystalline semiconductor devices. Although the electronic or optoelectronic performance of these solution processed devices is typically inferior to that of those fabricated by conventional routes, this can be tolerated for some applications in view of the other benefits. Here we report the fabrication of solution processed infrared photodetectors that are superior in their normalized detectivity (D* the figure of merit for detector sensitivity) to the best epitaxially grown devices operating at room temperature. We produced the devices in a single solution processing step, overcoating a prefabricated planar electrode array with an unpatterned layer of PbS colloidal quantum dot nanocrystals. The devices showed large photoconductive gains with responsivities greater than 103 A W 1. The best devices exhibited a normalized detectivity D* of 1.8 x 1013 jones (1 jones 1 cm Hz1/2 W 1) at 1.3 um at room temperature: today's highest performance infrared photodetectors are photovoltaic devices made from epitaxially grown InGaAs that exhibit peak D* in the 1012 jones range at room temperature, whereas the previous record for D* from a photoconductive detector lies at 1011 jones. The tailored selection of absorption onset energy through the quantum size effect, combined with deliberate engineering of the sequence of nanoparticle fusing and surface trap functionalization, underlie the superior performance achieved in this readily fabricated family of devices.
author_names: Gerasimos Konstantatos

I Howard

Armin Fischer

Sjoerd Hoogland

Jason Paul Clifford

Ethan J D Klem

Larissa Levina

Edward H Sargent
title: Ultrasensitive solution cast quantum dot photodetectors
venue: Nature
year: 2006

abstract: InGaAs based photodetectors have been generally used for detection in the short wave infrared (SWIR) region. However, the epitaxial process used to grow these materials is expensive; therefore, InGaAs based photodetectors are limited to space exploration and military applications. Many researchers have expended considerable efforts to address the problem of SWIR photodetector development using lead sulfide (PbS) quantum dots (QDs) Along with their cost efficient solution processability and flexible substrate compatibility, PbS QDs are highly interesting for the quantum size effect tunability of their bandgaps, spectral sensitivities, and wide absorption ranges. However, the performance of PbS QD based SWIR photodetectors is limited owing to inefficient carrier transfer and low photo and thermal stabilities. In this study, a simple method is proposed to overcome these problems by incorporating CdS in PbS QD shells to provide efficient carrier transfer and enhance the long term stability of SWIR photodetectors against oxidation. The SWIR photodetectors fabricated using thick shell PbS/CdS QDs exhibited a high on/off (light/dark) ratio of 11.25 and a high detectivity of 4.0 x 10 12 Jones, which represents a greater than 10 times improvement in these properties relative to those of PbS QDs. Moreover, the lifetimes of thick shell PbS/CdS QD based SWIR photodetectors were significantly improved owing to the self passivation of QD surfaces.
author_names: Jin-Beom Kwon

Sae-Wan Kim

Byoung-Ho Kang

Se-Hyuk Yeom

Wang-Hoon Lee

Dae-Hyuk Kwon

Jae-Sung Lee

Shin-Won Kang
title: Air stable and ultrasensitive solution cast SWIR photodetectors utilizing modified core/shell colloidal quantum dots
venue: Nano Convergence
year: 2020

abstract: 2D transition metal dichalcogenide (2D TMD) materials and their van der Waals heterostructures (vdWHs) have inspired worldwide efforts in the fields of electronics and optoelectronics. However, photodetectors based on 2D/2D vdWHs suffer from performance limitations due to the weak optical absorption of their atomically thin nature. In this work, taking advantage of an excellent light absorption coefficient, low temperature solution processability, and long charge carrier diffusion length, all inorganic halides perovskite CsPbI3 x Br x quantum dots are integrated with monolayer MoS2 for high performance and low cost photodetectors. A favorable energy band alignment facilitating interfacial photocarrier separation and efficient carrier injection into the MoS2 layer inside the 0D 2D mixed dimensional vdWHs are confirmed by a series of optical characterizations. Owing to the synergistic effect of the photogating mechanism and the modulation of Schottky barriers, the corresponding phototransistor exhibits a high photoresponsivity of 7.7 x 104 A W 1, a specific detectivity of 5.6 x 1011 Jones, and an external quantum efficiency exceeding 107% The demonstration of such 0D 2D mixed dimensional heterostructures proposed here would open up a wide realm of opportunities for designing low cost, flexible transparent, and high performance optoelectronics.
author_names: Hualin Wu

Haonan Si

Zihan Zhang

Zhuo Kang

Pingwei Wu

Lixin Zhou

Suicai Zhang

Zheng Zhang

Qingliang Liao

Yue Zhang
title: All Inorganic Perovskite Quantum Dot Monolayer MoS2 Mixed Dimensional van der Waals Heterostructure for Ultrasensitive Photodetector
venue: Advanced science
year: 2018

abstract: In article number 1801219, Zhuo Kang, Yue Zhang, and co workers fabricate an ultrasensitive photodetector based on an all inorganic perovskite quantum dot monolayer MoS2 mixed dimensional van der Waals heterostructure. Owing to the synergistic effect of photogating and Schottky barriers modulation, the corresponding phototransistor exhibits an ultrahigh photoresponsivity of 7.7 x 104 A W 1, a specific detectivity of 5.6 x 1011 Jones, and an external quantum efficiency exceeding 107%
author_names: Hualin Wu

Haonan Si

Zihan Zhang

Zhuo Kang

Pingwei Wu

Lixin Zhou

Suicai Zhang

Zheng Zhang

Qingliang Liao

Yue Zhang
title: Optoelectronics: All Inorganic Perovskite Quantum Dot Monolayer MoS2 Mixed Dimensional van der Waals Heterostructure for Ultrasensitive Photodetector (Adv. Sci. 12/2018)
venue: Advanced Science
year: 2018

abstract: Recently, two dimensional (2D) materials, especially transition metal dichalcogenides (TMDCs) have attracted extensive interest owing to their potential applications in optoelectronics. Here, we demonstrate a hybrid 2D zero dimensional (0D) photodetector, which consists of a single layer or few layer molybdenum disulfide (MoS2) thin film and a thin layer of core/shell zinc cadmium selenide/zinc sulfide (ZnCdSe/ZnS) colloidal quantum dots (QDs) It is worth mentioning that the photoresponsivity of the hybrid 2D 0D photodetector is 3 orders of magnitude larger than the TMDC photodetector (from 10 to 104 A W 1) The detectivity of the hybrid structure detector is up to 1012 Jones, and the gain is up to 105. Due to an effective energy transfer from the photoexcited QD sensitizing layer to MoS2 films, light absorption is enhanced and more excitons are generated. Thus, this hybrid 2D 0D photodetector takes advantage of high charge mobility in the MoS2 layer and efficient photon absorption/exciton generation in the QDs, which suggests their promising applications in the development of TMDC based optoelectronic devices.
author_names: Shukui Zhang

Xudong Wang

Yan Chen

Guangjian Wu

Yicheng Tang

Liqing Zhu

Haoliang Wang

Wei Jiang

Liaoxin Sun

Tie Lin

Hong Shen

Weida Hu

Jun Ge

Jianlu Wang

Xiangjian Meng

Jun-hao Chu
title: Ultrasensitive Hybrid MoS2 ZnCdSe Quantum Dot Photodetectors with High Gain.
venue: ACS applied materials interfaces
year: 2019

abstract: PbS colloidal quantum dots (CQDs) passivated by thiocyanate anion (SCN are developed to combine with perovskite (CH3NH3PbI3) as building blocks for UV vis NIR broadband pho todetectors. Both high electrical conductivity and appropriate energy level alignment are obtained by the in situ ligand exchange with SCN The PbS SCN/CH3NH3PbI3 composite photodetectors are sensitive to a broad wavelength range covering the UV vis NIR region (365 1550 nm) possessing an excellent responsivity of 255 AW 1 at 365 nm and 1.58 AW 1 at 940 nm, remarkably high detectivity of 4.9x1013 Jones at 365 nm and 3.0x1011 Jones at 940 nm, and a fast response time 42 ms. Furthermore, a 10x10 photodetector array is fabricated and integrated, which constitutes a high performance broadband image sensor. Our approach paves a way for the development of highly sensitive broadband photodetectors/imagers that can be easily integrated.
author_names: Jing-Yue Zhang

Jian-Long Xu

Tong Chen

Xu Gao

Sui-Dong Wang
title: Toward Broadband Imaging: Surface Engineered PbS Quantum Dot/Perovskite Composite Integrated Ultrasensitive Photodetectors.
venue: ACS applied materials interfaces
year: 2019

author_names: Jingzhou Li

Changjiu Teng

Bilu Liu

Guichuan Xing

Feiyu Kang
title: Ultrasensitive Organic Modulated CsPbBr 3 Quantum Dot Photodetectors via Fast Interfacial Charge Transfer
year: 2019

abstract: We report that spin cast colloidal quantum dot devices depend sensitively on exquisite control over surface passivation. We use these findings to quadruple infrared phovotovoltaic efficiency and build the first megahertz frequency solution cast photodiode.
author_names: D Aaron R Barkhouse

Jason Paul Clifford

Andras G Pattantyus-Abraham

Larissa Levina

Edward H Sargent
title: Engineering Quantum Dot Surfaces in Solution Processed Optoelectronics: Chemical Optimization of Photodetector and Photovoltaic Device Performance
year: 2009

abstract: Broadband photodetectors have important applications in both scientific and industrial sectors. In this study, we report room temperature operated solution processed photodetectors by PbSe quantum dots (QDs) with spectral response from 350 to 2500 nm. In order to boost both external quantum efficiency (EQE) and projected detectivity D* the hole trap assisted photomultiplication effect through the EDT PbSe QD/TABI PbSe QD double thin layer thin film, where EDT PbSe QDs are 1,2 ethanedithiol (EDT) capped PbSe QDs and TABI PbSe QDs are tetrabutylammonium (TABI) capped PbSe QDs, is applied. To further enhance D* a thin layer of the conjugated polyelectrolyte, which offers significant hole injection resistance for suppressing dark current but enhancing photocurrent under illumination due to the photoinduced self doping process, is applied for reengineering the electron extraction layer in PbSe QD based photodetectors. As a result, at room temperature, PbSe QD based photodetectors exhibit over 450% EQE and over ~1012 Jones D* in the visible region and over 120% EQE and D* ~4 x 1011 Jones in the infrared region. These results demonstrate that our studies provide a simple approach to realize room temperature operated solution processed broadband photodetectors.
author_names: Tao Zhu

Luyao Zheng

Xiang Yao

Lei Liu

Fei Huang

Yong Cao

Xiong Gong
title: Ultrasensitive Solution Processed Broadband PbSe Photodetectors through Photomultiplication Effect.
venue: ACS applied materials interfaces
year: 2019

abstract: Sensing from ultraviolet visible to infrared is critical for both scientific and industrial applications. In this work, we demonstrate solution processed ultrasensitive broad band photodetectors (PDs) utilizing organolead halide perovskite materials (CH3NH3PbI3) and PbS quantum dots (QDs) as light harvesters. Through passivating the structural defects on the surface of PbS QDs with diminutive molecular scaled CH3NH3PbI3, both trap states in the bandgap of PbS QDs for charge carrier recombination and the leakage currents occurring at the defect sites are significantly reduced. In addition, CH3NH3PbI3 itself is an excellent light harvester in photovoltaics, which contributes a great photoresponse in the ultraviolet visible region. Consequently, operated at room temperature, the resultant PDs show a spectral response from 375 nm to 1100 nm, with high responsivities over 300 mA W( 1) and 130 mA W( 1) high detectivities exceeding 10(13) Jones (1 Jones 1 cm Hz(1/2) W( 1) and 5 x 10(12) Jones in the visible and near infrared regions, respectively. These device performance parameters are comparable to those from pristine inorganic counterparts. Thus, our results offer a facile and promising route for advancing the performance of broad band PDs.
author_names: Chang Liu

Kai Wang

Pengcheng Du

Enmin Wang

Xiong Gong

Alan J Heeger
title: Ultrasensitive solution processed broad band photodetectors using CH3NH3PbI3 perovskite hybrids and PbS quantum dots as light harvesters.
venue: Nanoscale
year: 2015