Hybrid Phototransistors Research Articles

High Performance Hybrid‐Phototransistor Based on ZnON/perovskite Heterostructure Through Multi‐Functional Passivation

AbstractOrganic–inorganic halide perovskites are widely investigated for various optoelectronics devices such as photodetectors and solar cells. However, Pb‐based perovskite photodetectors perform poorly because of insufficient mobility and absence of an effective photoconductive gain mechanism. Herein, ZnON/perovskite heterostructures are demonstrated to realize the fabrication of high‐performance hybrid phototransistors. Additionally, a guanidinium iodide (GuI), alternating‐cation‐interlayer (ACI)‐type organic spacers, are utilized as an interface passivation layer. It is shown that the GuI interface layer reduces the defect density of the ZnON surface as well as the bulk perovskite film and promotes the separation and transport of photo‐generated charge carriers. Devices fabricated with the GuI interface passivation layer have a response speed of 0.1 s, excellent responsivity of 5.97 × 106 A W−1, and ultra‐high specific detectivity of 1.28 × 1018 Jones, the highest value among previously reported perovskite‐based hybrid phototransistors. This work provides valuable insights into the design and fabrication of high‐performance metal oxide/perovskite heterostructures with promising applications in future optoelectronic devices.

Photoresponse mediated by exciton-plasmon coupling in two-dimensional hybrid phototransistors

Photoresponse mediated by exciton-plasmon coupling in two-dimensional hybrid phototransistors

InP Quantum Dots Tailored Oxide Thin Film Phototransistor for Bioinspired Visual Adaptation

AbstractThe exploration of bionic neuromorphic chips, capable of processing sensory data in a human‐like manner, is both a trend and a challenge. There is a strong demand for phototransistors that offer broadband in‐sensor adaptability. This study introduces a bioinspired vision sensor based on InP quantum dots (QDs)/InSnZnO hybrid phototransistors. This novel design combines the excellent electrical transportation features of oxide semiconductors with the superior optoelectronic response of InP QDs. The resulting hybrid devices exhibit exceptional gate controllability and a robust visible‐light response. These characteristics enable the emulation of multiple functions of the human visual system and the accommodation of varying light intensity environments. Furthermore, the phototransistor array successfully replicates the scotopic and photopic adaptation recognition behaviors of the human retina. Notably, the device demonstrates faultless competency in image processing, achieving an impressive 93% accuracy for digit recognition. These findings contribute to the advancement of bionic neuromorphic chips and offer promising opportunities for future developments in the bioinspired visual system.

Solution-Processed Organic–Inorganic Semiconductor Heterostructures for Advanced Hybrid Phototransistors

Organic/inorganic hybrid phototransistors are an emerging class of advanced optoelectronic devices. The separated organic high absorption layer and inorganic carrier transport layer endow hybrid phototransistors with remarkable sensing performance in a broad spectrum. The flexibility, ambient stability, and process compatibility of organic and metal oxide semiconductors also render them promising for large-area matrix integration and wearable applications. Moreover, extraordinary photoelectric behaviors, such as bidirectional photoresponses and the versatility of in-sensor computing functions, including feature extraction and image enhancement, can be obtained by rational customization of the hybrid heterojunctions. In this Spotlight on Applications, we review the recent progress of organic/inorganic hybrid phototransistors and their applications in photodetection, sensor arrays, flexible electronics, and in-sensor computing.

Interface Defects Tuning in Polymer‐Perovskite Phototransistors for Visual Synapse and Adaptation Functions

AbstractArtificial sensory nerves can simulate the functions of visual perception and information processing of the human brain, which is indispensable for the immediate visualization of the environment and awareness requisite to avoid the potential harm. However, it still remains a long‐standing challenge to integrate recognition learning with real‐time processing function in a single device. Herein, an interface defects‐tuning strategy is proposed for developing a novel bi‐functional phototransistor. Benefiting from the tuned polymer‐perovskite layer‐heterointerface defects, the photogenerated charge trapping and de‐trapping capacities are significantly improved, thereby facilitating the photogenerated carrier separation and injection. The prepared organic‐inorganic hybrid phototransistors can perfectly mimic the human visual synaptic behaviors with a quick response speed (<35 ms, far below that of human eyes to incident light (225 ms)). More importantly, the phototransistor exhibited obvious visual adaptation toward wide‐ranging light stimuli, and realized unique desensitization to simulate the self‐protection behavior of the human visual systems. Specifically, the adaptation timescales of the device under dim and high light conditions are superior to bio‐systems (<2 min). Consequently, the reported strategy for the preparation of bi‐functional phototransistors provides a brand‐new perspective for next‐generation artificial nervous systems.

Analysis of Carrier Transport in Quantum Dot/Metal‐Oxide Phototransistors via Light‐Mediated Interfacial Modeling

AbstractQuantum dot (QD) hybrid phototransistors based on high‐mobility channel semiconductors have attracted great interest due to their outstanding photonic characteristics with diverse and broadband optoelectronic functionalities. However, difficulties for precise control of electronic coupling between QD particles and lack of QD/semiconductor interface analysis have limited the use of these platforms into practical optoelectronic applications. Here, the authors report a new strategy to high‐performance phototransistors based on CdSe QD/amorphous oxide semiconductor heterostructures using trap‐reduced chelating chalcometallate surface ligands by optimizing the QD layer thickness and interface engineering to enhance photogenerated charge transfer properties. Furthermore, based on performance parameters extracted from experimental structure and electrical characteristics, Technology Computer‐Aided Design (TCAD) modeling reveals carrier flow between the QDs in the semiconductor layer in agreement with various spectroscopic data. These modeling results indicate that interface engineering of QD with chalcometallate ligand results in very efficient photo‐induced charge transfer characteristics. Thus, high‐performance chalcometallate ligand QD‐based phototransistors are successfully realized with enhanced responsivity (2.12 × 104 A W−1) and photodetectivity (2.74 × 1016 Jones) compared with conventional monodentate ligand functionalized (SCN−) QD‐based devices (8.79 × 103 A W−1 and 8.8 × 1010 Jones, respectively). This is the demonstration of systematic analysis of QD‐based hetero‐structured phototransistors with light‐mediated interfacial physical modeling and electrochemical measurement.

Schottky-Contact Hybrid Phototransistors With Bidirectional Photoresponses for Ultraviolet and Infrared Light Differentiating

Bidirectional photoresponses (BPR) are significant, yet rare in conventional optoelectronic systems. In this letter, we achieve BPR in the inorganic-organic semiconductors hybrid phototransistors (HPTs) by introducing Schottky contact at metal-semiconductor interfaces. The Schottky contact enables the HPTs with distinguishable positive and negative photoresponses to ultraviolet and near-infrared light, respectively, capable of differentiating incident light wavelengths. Our results provide an efficient solution to achieve BPR, promising for wavelength differentiating and advanced optoelectronic sensors.

Enhanced performance and stability in InGaZnO NIR phototransistors with alumina-infilled quantum dot solid

The optimized ALD infilling process for depositing Al2O3 in the vertical direction of PbS QDs enhances the photoresponsivity, relaxation rate and the air stability of PbS QDs hybrid IGZO NIR phototransistors. Infilled Al2O3, which is gradually deposited from the top of PbS QDs to the PbS/IGZO interface (1) passivates the trap sites up to the interface of PbS/IGZO without disturbing charge transfer and (2) prevents QDs deterioration caused by outside air. Therefore, an Al2O3 infilled PbS QD/IGZO hybrid phototransistor (AI-PTs) exhibited enhanced photoresponsivity from 96.4 A/W to 1.65 × 102 A/W and a relaxation time decrease from 0.52 to 0.03 s under NIR light (880 nm) compared to hybrid phototransistors without Al2O3 (RF-PTs). In addition, AI-PTs also showed improved shelf stability over 4 months compared to RF-PTs. Finally, all devices we manufactured have the potential to be manufactured in an array, and this ALD technique is a means of fabricating robust QDs/metal oxide hybrids for optoelectronic devices.

Inorganic-Organic Hybrid Phototransistor Array with Enhanced Photogating Effect for Dynamic Near-Infrared Light Sensing and Image Preprocessing.

Narrow-band-gap organic semiconductors have emerged as appealing near-infrared (NIR) sensing materials by virtue of their unique optoelectronic properties. However, their limited carrier mobility impedes the implementation of large-area, dynamic NIR sensor arrays. In this work, high-performance inorganic-organic hybrid phototransistor arrays are achieved for NIR sensing, by taking advantage of the high electron mobility of In2O3 and the strong NIR absorption of a BTPV-4F:PTB7-Th bulk heterojunction (BHJ) with an enhanced photogating effect. As a result, the hybrid phototransistors reach a high responsivity of 1393.0 A W-1, a high specific detectivity of 4.8 × 1012 jones, and a fast response of 0.72 ms to NIR light (900 nm). Meanwhile, an integrated 16 × 16 phototransistor array with a one-transistor-one-phototransistor (1T1PT) architecture is achieved. On the basis of the enhanced photogating effect, the phototransistor array can not only achieve real-time, dynamic NIR light mapping but also implement image preprocessing, which is promising for advanced NIR image sensors.

Skin-conformable photoplethysmogram sensors for energy-efficient always-on cardiovascular monitoring systems

Skin-conformable photoplethysmogram (PPG) sensors enable continuous and accurate monitoring of physiological states to efficiently prevent cardiovascular-related diseases. Herein, novel PPG sensors consisting of polymer/oxide hybrid phototransistors, mini-light-emitting diodes, and a framework conformable to epidermis are developed. The key element, a heterojunction phototransistor for efficient energy usage, is composed of an indium gallium zinc oxide (IGZO)-based active layer for low-power consumption and a specific diketopyrrolopyrrole (DPP) polymer layer affording high near-infrared (NIR) light absorbability and hydrophobicity. Therefore, the phototransistors with NIR detectivity of 1.00 × 1013 Jones, rapid photoresponse within the human heart rate range, high reliability against perspiration and mechanical stress, and low operating voltages (< 5 V) are achieved. Using the developed PPG sensors, the heart rate and oxygen saturation of human subjects are successfully detected, which is comparable to the commercial PPG sensors. Furthermore, controlling potential barrier energy at the interface between heterojunction layers, PPG sensors that operate separately at low and high heart rates are implemented for continuous monitoring. Consequently, a distinguished configuration of skin-conformable PPG sensors and a novel concept of an always-on cardiovascular monitoring system while consuming less power are suggested. The study contributes to the development of PPG sensors and may become a potential solution for Healthcare 4.0 applications.

Flexible and Air‐Stable Near‐Infrared Sensors Based on Solution‐Processed Inorganic–Organic Hybrid Phototransistors

AbstractFlexible and air‐stable phototransistors are highly demanded for wearable near‐infrared (NIR) image sensors. However, advanced NIR sensors via low‐cost, solution‐based processes remained a challenge. Herein, high‐performance inorganic–organic hybrid phototransistors are achieved based on solution processed n‐type metal oxide/polymer semiconductor heterostructures of In2O3/poly{5,5′‐bis[3,5‐bis(thienyl)phenyl]‐2,2′‐bithiophene‐3‐ethylesterthiophene]} (PTPBT‐ET). The In2O3/PTPBT‐ET hybrid phototransistor combines the advantages of both fast electron transport in In2O3 and high photoresponse in PTPBT‐ET, showing high saturation mobility of 7.1 cm2 V−1 s−1 and large current on/off ratio of &gt;107. As a result, the phototransistor exhibits high performance towards NIR light sensing with a responsivity of 200 A W−1, a specific detectivity of 1.2 × 1013 Jones, and fast photoresponse with rise/fall time of 5/120 ms. Remarkably, the hybrid phototransistor, without any passivation, demonstrates excellent electrical stability without performance degradation even after 160 days in air. A 10 × 10 phototransistor array is also enabled by virtue of the high device uniformity. Lastly, flexible In2O3/PTPBT‐ET phototransistor on polyimide substrate is attained, exhibiting outstanding mechanical flexibility up to 1000 bending/releasing cycles at a bending radius of 5 mm. These achievements pave the way for constructing air‐stable hybrid phototransistors for flexible NIR image sensor applications.

Optical modulation frequency mediated tunable response time and responsivity in graphene-PbS QD based hybrid photodetectors

Graphene/lead sulfide (PbS) quantum dot (QD) hybrid infrared photodetectors have gained a lot of attention in recent times due to their high resolution and cost effective fabrication process. In spite of exhibiting remarkably high responsivity, such hybrid detectors are slow as a result of their internal gain mechanism process. In this work, we present a convenient strategy to modulate the correlation between their responsivity and response time giving access to high resolution fast photodetectors in the broadband wavelength range for imaging purpose. Using a layer-by-layer deposition technique including simultaneous ligand exchange and surface passivation at each layer, homogeneous PbS QD films on chemical vapour deposition grown single layer graphene could be achieved. The obtained hybrid phototransistors exhibit a high responsivity of 108 A W−1 and sensitivity down to 0.1 pW incident light power in the near-infrared wavelength range. By modulating the incident light at a modulation frequency up to 50 kHz, we achieve a response time as low as 5 μs while preserving a much higher responsivity (144 A W−1) compared to existing commercial room temperature infrared photodetectors.

Weak Light-Stimulated Synaptic Hybrid Phototransistors Based on Islandlike Perovskite Films Prepared by Spin Coating.

An artificial synaptic device that can provide color discrimination, image storage, and image recognition is highly required to mimic the human vision for biological robots. All-inorganic halide perovskites have attracted extensive attention for the reason of their high stability and favorable photoelectric properties. In this study, a light-stimulated synaptic phototransistor based on a CsPbBr3/organic semiconductor hybrid film is reported. The fabricated CsPbBr3 film exhibits an island structure, which reduces the hysteresis effectively and at the same time achieves a high specific detectivity of up to 2 × 1015 Jones. The decay of the photocurrent can be delayed by changing the gate bias, which is essential for achieving high-performance light-stimulated synaptic devices. Due to the outstanding detectivity of the device, the obvious synaptic functions can be observed when triggered by a light signal with a power of 1.6 nW that is much weaker than previous most perovskite-based hybrid synaptic phototransistors under a low operating voltage of -1 V. The electrical power consumption of the device could be as low as 0.076 pJ when the power of light spike was 7.36 nW. Taking into account this characterization, with changing of light intensity or wavelength, the contrast of the image was enlarged, which can further promote the image recognition accuracy. More significantly, this CsPbBr3/TIPS hybrid film can be fabricated by facile and low-cost solution processes. This study indicates the great potential of solution-processed perovskite-based light-stimulated synapses for future artificial visual systems.

Correlation Between Surface Functionalization and Optoelectronic Properties in Quantum Dot Phototransistors

Quantum dot (QD)-based optoelectronics have attracted significant interest for extensive applications due to their unique photo-functionalities such as excellent optical absorption coefficient, size-dependent bandgap tunability, and facile solution processability. However, the charge transfer correlation between surface functionalization and optoelectronic properties is still not clear. Here, we report highly photosensitive CdSe QDs/solution-processed amorphous oxide semiconductor hybrid phototransistors with highly efficient photo-induced charge carrier transport using molecular metal chalcogenide (MCC) ligands surface functionalization. Furthermore, we comprehensively investigated the photo-induced electron transfer characteristics with respect to various MCC ligands such as Sn <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4-</sup> , Sn <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Se <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4-</sup> , and In <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Se <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2-</sup> . In particular, the interplay among photosensitive chelating MCC ligands of the QDs and trap-free optoelectronic performance of phototransistors was investigated. Compared to a-IGZO thin-film transistors and oleic acid-based CdSe QDs/ a-IGZO phototransistors, Sn <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> 6</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> 4-</sup> , Sn <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Se <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> 6</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> 4-</sup> , and In <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Se <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> 4</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> 2-</sup> -based CdSe QD/ a-IGZO phototransistors exhibited ultrahigh photosensitivity of 8.3×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> 3</sup> AW <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> , 3.1×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> 2</sup> AW <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> , and 1.3×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> 4</sup> AW <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> , respectively, in a broad range of incident light power (0.34 mW cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> -11.8 mW cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> ).

Inclined Ultrathin Bi2O2Se Films: A Building Block for Functional van der Waals Heterostructures.

As an emerging ultrathin semiconductor material, Bi2O2Se exhibits prominent performances in electronics, optoelectronics, ultrafast optics, etc. However, until now, the in-plane growth of Bi2O2Se thin films is mostly fulfilled on atomically flat mica substrates with interfacial electrostatic forces setting obstacles for Bi2O2Se transfer to fabricate functional van der Waals heterostructures. In this work, controlled growth of inclined Bi2O2Se ultrathin films is realized with apparently reduced interfacial contact areas upon mica flakes. Consequently, the transfer of Bi2O2Se could be facile by overcoming weaker electrostatic interactions. From cross-sectional characterizations at the Bi2O2Se/mica interfaces, it is found that there are no oxide buffer layers in existence for both in-plane and inclined growths, while the un-neutralized charge density is apparently decreased for inclined films. By mechanical pressing, inclined Bi2O2Se could be transferred onto SiO2/Si substrates, and back-gated Bi2O2Se field effect transistors are fabricated, outperforming previously reported in-plane Bi2O2Se devices transferred with the assistance of corrosive acids and adhesive polymers. Furthermore, Bi2O2Se/graphene heterostructures are fulfilled by a probe tip to fabricate hybrid phototransistors with pristine interfaces, exhibiting highly efficient photoresponses. The results in this work demonstrate the potential of inclined Bi2O2Se to act as a building block for prospective van der Waals heterostructures.

High‐Performance Quasi‐2D Perovskite/Single‐Walled Carbon Nanotube Phototransistors for Low‐Cost and Sensitive Broadband Photodetection

Quasi‐2D Ruddlesden–Popper perovskites (RPPs) have emerged as promising functional materials for optoelectronics due to the highly tunable optoelectronic properties and have been considered as alternative candidates for semiconductors in photodetectors. However, RPPs normally show low carrier mobilities, which is unfavorable for the performance of photodetectors. Herein, a solution‐processed hybrid phototransistor based on RPP/single‐walled carbon nanotube (SWCNT) heterostructure is reported. A vertical composition gradient is formed upon RPP film preparation, which leads to a gradient type‐II heterojunction in the film. More importantly, the high carrier mobility of SWCNTs can result in ultrahigh responsivity and detectivity of 2 × 106 A W−1 and 7 × 1014 Jones, respectively. In addition, high on/off ratio of ≈103 can be achieved in the phototransistors. Herein, the high potential of RPP/SWCNT hybrid phototransistors as next‐generation photodetectors with superior sensitivity is demonstrated.

38‐1: Invited Paper: High‐Performance Metal‐Oxide Semiconductor based Optoelectronics

We investigated high‐performance amorphous metal‐oxide semiconductor based optoelectronics using low‐temperature and solution process technologies. In particular, metal‐oxide and quantum dots hybrid phototransistors exhibited ultra‐high photodetectivity up to 4×1017Jones in a broad range of detection wavelength from ultraviolet to infrared ranges. In addition, we employed artificial visual perception circuit based on metal‐oxide synaptic transistors with metal chalcogenide semiconductors for optoelectronic neuromorphic devices. We also demonstrated large‐scaled ultra‐flexible and stretchable device showing promising next‐generation wearable optoelectronics.

High-Response, Ultrafast-Speed, and Self-Powered Photodetection Achieved in InP@ZnS-MoS2 Phototransistors with Interdigitated Pt Electrodes

Various hybrid zero-dimensional/two-dimensional (0D/2D) systems have been developed to fabricate phototransistors with better performance compared to two-dimensional (2D) layered materials as well as broaden potential applications. Herein, we integrated environment-friendly InP@ZnS core-shell QDs with high efficiency of light absorption and light-emitting properties with bilayer MoS2 for the realization of 0D/2D mixed-dimensional phototransistors. Interdigitated (IDT) electrodes with Pt-patterned arrays, acting as light collectors as well as plasmonic resonators, can further enhance light harvesting from the InP@ZnS-MoS2 hybrid phototransistors, contributing to achieving a photoresponsivity as high as 1374 A·W-1. Moreover, thanks to the asymmetric Pt/MoS2 Schottky junction at the source/drain contact, a self-powered characteristic with an ultrafast speed of 21.5 μs was achieved, which is among the best performances for 2D layered material-based phototransistors. In terms of these features, we demonstrated the artificial synapse network with short-time plasticity based on the self-powered photodetection device. Our work reveals the great potential of 0D/2D hybrid phototransistors for high-response, ultrafast-speed, and self-powered photodetectors coupled with artificial neuromorphic function.

Highly Efficient Photo-Induced Charge Separation Enabled by Metal-Chalcogenide Interfaces in Quantum-Dot/Metal-Oxide Hybrid Phototransistors.

Quantum dot (QD)-based optoelectronics have received great interest for versatile applications because of their excellent photosensitivity, facile solution processability, and the wide range of band gap tunability. In addition, QD-based hybrid devices, which are combined with various high-mobility semiconductors, have been actively researched to enhance the optoelectronic characteristics and maximize the zero-dimensional structural advantages, such as tunable band gap and high light absorption. However, the difficulty of highly efficient charge transfer between QDs and the semiconductors and the lack of systematic analysis for the interfaces have impeded the fidelity of this platform, resulting in complex device architectures and unsatisfactory device performance. Here, we report ultrahigh detective phototransistors with highly efficient photo-induced charge separation using a Sn2S64--capped CdSe QD/amorphous oxide semiconductor (AOS) hybrid structure. The photo-induced electron transfer characteristics at the interface of the two materials were comprehensively investigated with an array of electrochemical and spectroscopic analyses. In particular, photocurrent imaging microscopy revealed that interface engineering in QD/AOS with chelating chalcometallate ligands causes efficient charge transfer, resulting in photovoltaic-dominated responses over the whole channel area. On the other hand, monodentate ligand-incorporated QD/AOS-based devices typically exhibit limited charge transfer with atomic vibration, showing photo-thermoelectric-dominated responses in the drain electrode area.

Substantially Improving Device Performance of All-Inorganic Perovskite-Based Phototransistors via Indium Tin Oxide Nanowire Incorporation.

All-inorganic halide perovskites (IHPs) have attracted enormous attention due to their intrinsically high optical absorption coefficient and superior ambient stabilities. However, the photosensitivity of IHP-based photodetectors is still restricted by their poor conductivities. Here, a facile design of hybrid phototransistors based on the CsPbBr3 thin film and indium tin oxide (ITO) nanowires (NWs) integrated into a InGaZnO channel in order to achieve both high photoresponsivity and fast response is reported. The metallic ITO NWs are employed as electron pumps and expressways to efficiently extract photocarriers from CsPbBr3 and inject electrons into InGaZnO. The obtained device exhibits the outstanding responsivity of 4.9 × 106 A W-1 , which is about 100-fold better than the previous best results of CsPbBr3 -based photodetectors, together with the fast response (0.45/0.55 s), long-term stability (200 h in ambient), and excellent mechanical flexibility. By operating the phototransistor in the depletion regime, an ultrahigh specific detectivity up to 7.6 × 1013 Jones is achieved. More importantly, the optimized spin-coating manufacturing process is highly beneficial for achieving uniform InGaZnO-ITO/perovskite hybrid films for high-performance flexible detector arrays. All these results can not only indicate the potential of these hybrid phototransistors but also provide a valuable insight into the design of hybrid material systems for high-performance photodetection.