Organic-inorganic Hybrid Photodetectors Research Articles

Fabrication of organic-inorganic hybrid device for optoelectronic applications: Charge carriers dynamics and photoresponse assessment

In this study, we introduce the fabrication of an organic-inorganic hybrid architecture for photodetection applications that is constructed from Ethyl Nile Blue (ENB) and p-type silicon. The optical absorption and emission spectra of the deposited ENB films are investigated yielding high UV–visible absorption features with a broad blue and violet emission band. The developed Ag/ENB/p-Si/Al heterojunction's microelectronic characteristics are assessed under dark conditions and at various temperatures (303−353) K. The variation of the barrier height and ideality factor with temperature are interpreted in detail. Considering the barrier height inhomogeneity, the modified Richardson constant has been estimated and found to be 30 A/cm2 K2. Analysis and discussion have been conducted about the charge carrier dynamics scenario under forward and reverse bias settings. The implemented hybrid device's photoresponse is evaluated at various light intensities (20–100 mW/cm2). In comparison to other organic-inorganic hybrid photodetectors, the manufactured hybrid device demonstrated a promising, stable, and reliable performance. The manufactured photodetector exhibited R, D* , LDR, SNR, and (tr/tf) time at power density 100 mW/cm2 of about 1.85 mA/W, 8.5 × 108 Jones, 55.9 dB, 626, and (69.7 ms/52.6 ms), respectively.

Solution Processed Photodetectors with PVK-WS2 Nanotube/Nanofullerene Organic-Inorganic Hybrid Films.

Organic-inorganic hybrid photodetectors have attracted increased interest due to their exceptional properties, such as flexibility, transparency, and low cost for many promising applications. Low-dimensional tungsten disulfide (WS2) nanostructures have outstanding electrical and optical properties, making them ideal candidates for ultrasensitive photodetector devices. In this paper, photodetectors were fabricated with hybrid thin films containing two different WS2 nanomaterials, one-dimensional (1D) WS2 nanotubes (WS2-NTs) and a zero-dimensional (0D) WS2 nanofullerene (WS2-FLs) hybrid with poly(N-vinyl carbazole) (PVK). The electrical responses of the devices under visible-light illuminations were studied. The photodetector devices with 0D WS2-FLs/PVK hybrid thin films have relatively higher sensitivity and stable voltage responses to visible light. Besides, the hybrid film shows a strong surface-enhanced Raman effect (SERS). These materials and new strategies enable the creation of a new class of processed photodetectors for practical applications.

Rare-Earth-Element-Ytterbium-Substituted Lead-Free Inorganic Perovskite Nanocrystals for Optoelectronic Applications.

Lead-(Pb-) halide perovskite nanocrystals (NCs) are interesting nanomaterials due to their excellent optical properties, such as narrow-band emission, high photoluminescence (PL) efficiency, and wide color gamut. However, these NCs have several critical problems, such as the high toxicity of Pb, its tendency to accumulate in the human body, and phase instability. Although Pb-free metal (Bi, Sn, etc.) halide perovskite NCs have recently been reported as possible alternatives, they exhibit poor optical and electrical properties as well as abundant intrinsic defect sites. For the first time, the synthesis and optical characterization of cesium ytterbium triiodide (CsYbI3 ) cubic perovskite NCs with highly uniform size distribution and high crystallinity using a simple hot-injection method are reported. Strong excitation-independent emission and high quantum yields for the prepared NCs are verified using photoluminescence measurements. Furthermore, these CsYbI3 NCs exhibit potential for use in organic-inorganic hybrid photodetectors as a photoactive layer. The as-prepared samples exhibit clear on-off switching behavior as well as high photoresponsivity (2.4 × 103 A W-1 ) and external quantum efficiency (EQE, 5.8 × 105 %) due to effective exciton dissociation and charge transport. These results suggest that CsYbI3 NCs offer tremendous opportunities in electronic and optoelectronic applications, such as chemical sensors, light emitting diodes (LEDs), and energy conversion and storage devices.

Recent Progress on Photomultiplication Type Organic Photodetectors

AbstractPhotodetectors as a significant unit of intelligent optoelectronic systems have stimulated immense attention from multidisciplinary areas. Photomultiplication (PM) is desirable for sensitive photodetectors with strong detection capability of weak light, which can further simplify the photo‐detection systems without pre‐amplifier circuit. For organic photodetectors (OPDs), PM phenomenon cannot be realized by utilizing the principle of avalanche effect or impact ionization as in inorganic materials, stemming from organic semiconductor materials with large exciton binding energy and disordered structure. In this review, the recent progress on PM type OPDs is comprehensively summarized from the perspective of device physics and material science. Charge tunneling injection induced by interfacial traps becomes the mainstream working mechanism for obtaining PM phenomenon. A series of PM type OPDs was achieved by utilizing interfacial blocking layer and introducing trap states into active layer or interfacial layer. The filter‐free PM type narrowband OPDs are realized by combining the concept of charge injection narrowing with the mechanism of PM. Meanwhile, further development on this hot topic is proposed and fully discussed, including multifunctional OPDs, organic–inorganic hybrid photodetectors, and photodetector systems.

Tuning the spectral response of ultraviolet organic-inorganic hybrid photodetectors via charge trapping and charge collection narrowing.

Organic-inorganic hybrid ultraviolet photodetectors with tunable spectral response are desirable for many different applications. In this work, we blended poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) with ZnO nanoparticles in weight ratios of 1 : 1 and 2 : 1 to create charge traps within the active layers for devices with the conventional structure ITO/PEDOT : PSS/PTAA : ZnO/BCP/Al. Thin (150-200 nm) and thick (1400-1900 nm) active layers were employed to utilize charge collection narrowing (CCN). Both thickness and composition of the active layer impacted the spectral tunability of the photoresponse. A single narrow response peak centered at 420 nm (the PTAA absorption edge) with a full width at half maximum of 12 nm was achieved from the device with a 1900 nm active layer and PTAA : ZnO weight ratio of 1 : 1. Decreasing the active layer thickness to 150 nm resulted in a broad spectral response between 320-420 nm with an external quantum efficiency (EQE) value of 295% under 350 nm illumination and a -1 V bias, exhibiting photomultiplication via charge trapping and injection even at small reverse biases. Increasing the weight ratio of PTAA : ZnO to 2 : 1 lowered both the dark current and photocurrent, eliminated photomultiplication in the thin device, and diminished the efficacy of CCN to narrow the spectral photoresponse in the thick device. Transfer matrix method (TMM) and 3-dimensional finite-difference time-domain (3D-FDTD) simulations were performed to understand the impact of thickness and composition of the active layer on the spectral response of UV photodetectors in terms of exciton generation rate and electric field distribution within the devices.

Flexible Photodetectors Based on 1D Inorganic Nanostructures.

Flexible photodetectors with excellent flexibility, high mechanical stability and good detectivity, have attracted great research interest in recent years. 1D inorganic nanostructures provide a number of opportunities and capabilities for use in flexible photodetectors as they have unique geometry, good transparency, outstanding mechanical flexibility, and excellent electronic/optoelectronic properties. This article offers a comprehensive review of several types of flexible photodetectors based on 1D nanostructures from the past ten years, including flexible ultraviolet, visible, and infrared photodetectors. High‐performance organic‐inorganic hybrid photodetectors, as well as devices with 1D nanowire (NW) arrays, are also reviewed. Finally, new concepts of flexible photodetectors including piezophototronic, stretchable and self‐powered photodetectors are examined to showcase the future research in this exciting field.

High performance organic-inorganic perovskite-optocoupler based on low-voltage and fast response perovskite compound photodetector.

Organic-inorganic hybrid photodetectors attract considerable attention because they can combine the advantages of both organic and inorganic systems. Here, a perovskite compound with a broad absorption spectrum and high power conversion efficiency is used as a photosensitive layer in an organic/inorganic hybrid heterojunction photodetector with a high and fast response. The high sensitivity exceeding 104 is obtained at bias of 0–4 V. Using a tandem organic light-emitting diode (OLED) as the light source, we fabricated an optocoupler device. The optocoupler achieved a maximum photoresponsivity of 1.0 A W−1 at 341.3 μWcm−2 at an input voltage of 6 V. The device also exhibits rapid response times of τrise ~ 20 μs and τfall ~ 17 μs; as well as a high current transfer ratio (CTR) of 28.2%. After applying an amplification circuit, the CTR of the optocoupler increases to 263.3%, which is comparable with that of commercial inorganic optocouplers. The developed hybrid optocoupler thus shows great promise for use in photonics.

Flexible organic-inorganic hybrid photodetectors with n-type phenyl-C61-butyric acid methyl ester (PCBM) and p-type pearl-like GaP nanowires

Flexible photodetectors have become a focus of current researches because they may offer some unique applications in various new areas that require flexible, lightweight, and mechanical shock-resistive sensing elements. In this work, we designed flexible organic-inorganic hybrid photodetectors on various flexible substrates, including polyethylene terephthalate (PET), common Sellotape and polydimethylsiloxane (PDMS), with n-type phenyl-C61-butyric acid methyl ester (PCBM) and p-type pearl-like GaP nanowires (NWs) as the active materials. The as-fabricated hybrid devices exhibited an optimized performance superior to the device made of pristine GaP NWs, with a fast response time (43 ms) and high on/off ratio (∼170). Under different bending conditions, the flexible hybrid photodetectors demonstrated excellent flexibility and electrical stability, which make them very promising for further large-scale, high sensitivity and high speed photodetector applications.

ZnO(N)–Spiro-MeOTAD hybrid photodiode: an efficient self-powered fast-response UV (visible) photosensor

Organic-inorganic hybrid photo-detectors with a self-sufficient mode of operation represent a research area of great current interest. In most efficient photodetectors and optoelectronic devices compound semiconductors containing toxic elements such as Cd, As, Te, S, Se etc. are used and these are also expensive. Hence there is also a rapidly growing interest in replacing these with environmentally friendly and earth-abundant materials. Herein, we report a facile solution-processed fabrication of a self-powered organic-inorganic hybrid photodetector using n-type oriented ZnO nanorods and p-type Spiro-MeOTAD semiconductor. ZnO is eco-friendly and earth-abundant, and Spiro-MeOTAD is non-hazardous. We show that the latter has far less toxicity than the toxic elements stated above. This visible blind UV photodetector shows high sensitivity (10(2)) and a UV/visible rejection ratio of 300. It also exhibits fast response times of τ(rise) ~ 200 μs and τ(fall) ~ 950 μs. Importantly, with a small modification of nitrogen incorporation in ZnO one can also realize a highly-sensitive self-powered visible light photodetector with at least 1000% (or higher) improvements in quality factors (photocurrent/sensitivity/response time) as compared to previously reported organic-inorganic hybrid photo-detectors based on metal-chalcogenides (CdS-PANI or CuInSe2-P3HT). Interestingly, the broadband sensitivity of such N:ZnO-Spiro-MeOTAD photodiode enables sensing of low intensity (~28 μW cm(-2)) ambient white light with a high photocurrent density of 120 nA cm(-2) making it an efficient ambient white light detector.

Topological Structural Transformations of Nanoparticle Self-Assemblies Mediated by Phase Transfer and Their Application as Organic–Inorganic Hybrid Photodetectors

Nanoparticle (NP) self-assemblies have attracted an increasing amount of attention in recent years because of their potential application in the construction of novel nanodevices. The controllable transformation of NP self-assemblies (NPS) between a polar and nonpolar environment is required for many specific applications because of their different properties in different environments. In this article, water-soluble luminescent CdS/CdTe NPS were synthesized using thioglycolic acid as a capping agent. The stiff and straight NPS bundles became loose after phase transfer from an aqueous to an organic phase. Subsequently, the NPS transferred to the aqueous phase. The loose structure transformed into many twisted nanoribbons. Additionally, hybrid photodetectors made using the organic-soluble NPS and P3HT polymers were fabricated, and we found that the NPS/P3HT blend may be perfect for light detection. The organic-soluble NPS are potentially useful for the fabrication of semiconductor nanojunctions.

Controlled synthesis of AgInS2 nanocrystals and their application in organic–inorganic hybrid photodetectors

High quality AgInS2 nanocrystals (NCs) are synthesized using a simple single-source precursor method, in which the size and morphology of the products can be precisely controlled from heliotrope seed-like NCs of 6 × 12 nm to heliotrope seed-like dimer NCs of 8 × 16 nm by tuning the composition of the coordinating solvents of oleic acid and 1-dodecanethiol. The results show that 1-dodecanethiol plays a dominant role in determining the morphology of AgInS2 NCs due to its strong absorption onto the {001} crystal plane of AgInS2 NCs. The photoelectric properties of the as-prepared AgInS2 NCs have been characterized using AgInS2-poly(3-hexylthiophene) hybrid nanodevices. The results illustrate that the AgInS2 NCs present very high photosensitivity and photostability to outside illumination. The high sensitivity and stability of the hybrid nanodevice indicate a broad spectrum of applications in the photoelectric nanodevices.

Facile Synthesis of Germanium Nanocrystals and Their Application in Organic–Inorganic Hybrid Photodetectors

A solution-based method is developed for the synthesis of colloidal Ge nanocrystals (NCs), which directly grow from germanium(II) bromide in an oleylamine solution with no extra reducing agents. Hybrid photodetectors based on the NCs and poly(3-hexylthiophene) (P3HT) show promise for large-area applications, as revealed by their high photoresponse ratio, high sensitivity, and high stability.