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15 pages, 1025 KiB

Open AccessArticle

Gram-Scale Synthesis and Optical Properties of Self-Trapped-Exciton-Emitting Two-Dimensional Tin Halide Perovskites

by Yifeng Xing, Jialin Yin, Yifei Qiao, Jie Zhao, Haiyang He, Danyang Zhao, Wanlu Zhang, Shiliang Mei and Ruiqian Guo

Nanomaterials 2025, 15(11), 818; https://doi.org/10.3390/nano15110818 (registering DOI) - 28 May 2025

Abstract

Lead halide perovskites (LHPs) have superior luminescent properties, but their toxicity hinders their commercialization, arousing interests in tin halide perovskites as environmentally friendly substitutes for LHPs. Herein, we synthesized a series of two-dimensional tin halide perovskite ODASnBr_4-xI_x (ODA denotes 1,8-octanediammonium, [...] Read more.

Lead halide perovskites (LHPs) have superior luminescent properties, but their toxicity hinders their commercialization, arousing interests in tin halide perovskites as environmentally friendly substitutes for LHPs. Herein, we synthesized a series of two-dimensional tin halide perovskite ODASnBr_4-xI_x (ODA denotes 1,8-octanediammonium, X = 0, 1, 2, 3, 4) microcrystals via an aqueous-phase method. The differences between ODASnI₄ and ODASnBr₄ in luminescent properties and morphological characteristics were systematically discussed for the first time and attributed to light-driven ligand-to-metal charge transfer. The prepared ODASnBr₄ has a PL peak at 567 nm and a PL QY of 99%, and the white light-emitting diodes fabricated with ODASnBr₄ and commercial blue phosphors realized a luminous efficacy of up to 96.27 lm/W, which demonstrated the remarkable potential of ODASnBr₄ microcrystals for high-efficiency white light-emitting diode applications. Full article

(This article belongs to the Special Issue Advanced Research on Low-Dimensional Optoelectronic Nanomaterials and Nanodevices)

12 pages, 2733 KiB

Open AccessArticle

Enhanced Resistive Switching and Conduction Mechanisms in Silk Fibroin-Based Memristors with Ag Nanoparticles for Bio-Neuromorphic Applications

by Jongyun Choi, Seung Hun Lee, Taehun Kim, Kyungtaek Min and Sung-Nam Lee

Nanomaterials 2025, 15(7), 517; https://doi.org/10.3390/nano15070517 - 29 Mar 2025

Viewed by 319

Abstract

This study explores the resistive switching (RS) behavior and conduction mechanisms of Ag/SF-Ag NP/Si memristors with varying Ag NP concentrations. I-V measurements confirm stable RS characteristics across 100 cycles, with consistent set and reset voltages. Increasing Ag NP concentration enhances conductive filament formation, [...] Read more.

This study explores the resistive switching (RS) behavior and conduction mechanisms of Ag/SF-Ag NP/Si memristors with varying Ag NP concentrations. I-V measurements confirm stable RS characteristics across 100 cycles, with consistent set and reset voltages. Increasing Ag NP concentration enhances conductive filament formation, leading to sharper switching transitions and a higher HRS/LRS ratio, w-hich increases from 43 (0 wt% Ag NP) to 4.6 × 10⁴ (10 wt% Ag NP). Log(I)-log(V) analysis reveals a conduction transition from Ohmic to Poole–Frenkel mechanisms, indicating improved charge percolation. Reliability tests show stable LRS values, while HRS exhibits greater variation at higher Ag NP concentrations. These results demonstrate that Ag NPs play a crucial role in optimizing memristor performance, improving switching characteristics, and enhancing reliability. The findings suggest that Ag/SF-Ag NP/Si memristors are promising for high-performance resistive memory and neuromorphic computing applications. Full article

(This article belongs to the Special Issue Advanced Research on Low-Dimensional Optoelectronic Nanomaterials and Nanodevices)

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9 pages, 2329 KiB

Open AccessArticle

Broadband Graphene-PbS Heterostructure Photodetector with High Responsivity

by Xinbo Mu, Jinbao Su, Wenjuan Zhou, Pengying Chang, Jun Deng, Ying Liu, Zhengtai Ma and Yiyang Xie

Nanomaterials 2025, 15(3), 207; https://doi.org/10.3390/nano15030207 - 28 Jan 2025

Cited by 1 | Viewed by 1006

Abstract

Graphene-based photodetectors exhibit relatively low spectral absorption and rapid recombination of photogenerated carriers, which can limit their response performance. On the other hand, nanostructured lead sulfide (PbS) demonstrates a wide spectral absorption range from visible to near-infrared light. High-quality and evenly distributed PbS [...] Read more.

Graphene-based photodetectors exhibit relatively low spectral absorption and rapid recombination of photogenerated carriers, which can limit their response performance. On the other hand, nanostructured lead sulfide (PbS) demonstrates a wide spectral absorption range from visible to near-infrared light. High-quality and evenly distributed PbS nanofilms were synthesized by chemical bath deposition and were applied to a graphene-PbS heterostructure photodetector. The heterostructure creates an inherent electric field that extends the lifetime of photogenerated carriers, leading to enhanced device response. We achieved a high-responsivity graphene-PbS photodetector by combining the high carrier mobility of graphene and the strong infrared absorption of PbS. The photodetector exhibits a responsivity of 72 A/W at 792 nm and 5.8 A/W at 1550 nm, with a response time of less than 20 ms. The optimized device features a broad spectral response ranging from 265 nm to 2200 nm. Full article

(This article belongs to the Special Issue Advanced Research on Low-Dimensional Optoelectronic Nanomaterials and Nanodevices)

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13 pages, 4362 KiB

Open AccessArticle

High-Performance Self-Powered Dual-Mode Ultraviolet Photodetector Based on (PEA)₂PbI₄/GaN Heterojunction

by Ang Bian, Songchao Shen, Chen Yang and Jun Dai

Nanomaterials 2024, 14(22), 1819; https://doi.org/10.3390/nano14221819 - 13 Nov 2024

Viewed by 1273

Abstract

Wide-bandgap semiconductors like GaN, known for their superior photoresponse and detection capabilities in the ultraviolet range, represent a foundational component in the design of advanced photodetectors, where the integration of materials with distinct spectral sensitivities into heterojunctions is pivotal for next-generation device innovation. [...] Read more.

Wide-bandgap semiconductors like GaN, known for their superior photoresponse and detection capabilities in the ultraviolet range, represent a foundational component in the design of advanced photodetectors, where the integration of materials with distinct spectral sensitivities into heterojunctions is pivotal for next-generation device innovation. A high-performance self-powered dual-mode ultraviolet photodetector based on a (PEA)₂PbI₄/GaN heterojunction was fabricated via spin coating. The device exhibits outstanding UV sensitivity under both positive and negative bias, achieving a responsivity of 1.39 A/W and a detectivity of 8.71 × 10¹⁰ Jones under 365 nm UV illumination. The built-in electric field at the heterojunction interface enables self-powered operation, achieving a rapid rise time of 46.9 ms and a decay time of 55.9 ms. These findings offer valuable insights into the development and application of perovskite and wide-bandgap semiconductor heterojunctions in optoelectronic devices. Full article

(This article belongs to the Special Issue Advanced Research on Low-Dimensional Optoelectronic Nanomaterials and Nanodevices)

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18 pages, 2288 KiB

Open AccessArticle

Ratiometric Fluorescent pH Sensing with Carbon Dots: Fluorescence Mapping across pH Levels for Potential Underwater Applications

by Wiktoria Karolina Szapoczka, Chiara Olla, Cristina Carucci, Adam Leo Truskewycz, Tore Skodvin, Andrea Salis, Carlo Maria Carbonaro, Bodil Holst and Peter James Thomas

Nanomaterials 2024, 14(17), 1434; https://doi.org/10.3390/nano14171434 - 2 Sep 2024

Cited by 1 | Viewed by 1825

Abstract

Ocean acidification has become a major climate change concern requiring continuous observation. Additionally, in the industry, pH surveillance is of great importance. Consequently, there is a pressing demand to develop robust and inexpensive pH sensors. Ratiometric fluorescence pH sensing stands out as a [...] Read more.

Ocean acidification has become a major climate change concern requiring continuous observation. Additionally, in the industry, pH surveillance is of great importance. Consequently, there is a pressing demand to develop robust and inexpensive pH sensors. Ratiometric fluorescence pH sensing stands out as a promising concept. The application of carbon dots in fluorescent sensing presents a compelling avenue for the advancement of pH-sensing solutions. This potential is underpinned by the affordability of carbon dots, their straightforward manufacturing process, low toxicity, and minimal susceptibility to photobleaching. Thus, investigating novel carbon dots is essential to identify optimal pH-sensitive candidates. In this study, five carbon dots were synthesized through a simple solvothermal treatment, and their fluorescence was examined as a function of pH within the range of 5–9, across an excitation range of 200–550 nm and an emission range of 250–750 nm. The resulting optical features showed that all five carbon dots exhibited pH sensitivity in both the UV and visible regions. One type of carbon dot, synthesized from m-phenylenediamine, displayed ratiometric properties at four excitation wavelengths, with the best results observed when excited in the visible spectrum at 475 nm. Indeed, these carbon dots exhibited good linearity over pH values of 6–9 in aqueous Carmody buffer solution by calculating the ratio of the green emission band at 525 nm to the orange one at 630 nm (

I_{525 nm}

/

I_{630 nm}

), demonstrating highly suitable properties for ratiometric sensing. Full article

(This article belongs to the Special Issue Advanced Research on Low-Dimensional Optoelectronic Nanomaterials and Nanodevices)

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17 pages, 5118 KiB

Open AccessArticle

Utilizing Gold Nanoparticle Decoration for Enhanced UV Photodetection in CdS Thin Films Fabricated by Pulsed Laser Deposition: Exploiting Plasmon-Induced Effects

by Walid Belaid, Serap Yiğit Gezgin, Mohamed A. Basyooni-M. Kabatas, Yasin Ramazan Eker and Hamdi Şükür Kiliç

Nanomaterials 2024, 14(5), 416; https://doi.org/10.3390/nano14050416 - 24 Feb 2024

Cited by 4 | Viewed by 1688

Abstract

UV sensors hold significant promise for various applications in both military and civilian domains. However, achieving exceptional detectivity, responsivity, and rapid rise/decay times remains a notable challenge. In this study, we address this challenge by investigating the photodetection properties of CdS thin films [...] Read more.

UV sensors hold significant promise for various applications in both military and civilian domains. However, achieving exceptional detectivity, responsivity, and rapid rise/decay times remains a notable challenge. In this study, we address this challenge by investigating the photodetection properties of CdS thin films and the influence of surface-deposited gold nanoparticles (AuNPs) on their performance. CdS thin films were produced using the pulsed laser deposition (PLD) technique on glass substrates, with CdS layers at a 100, 150, and 200 nm thickness. Extensive characterization was performed to evaluate the thin films’ structural, morphological, and optical properties. Photodetector devices based on CdS and AuNPs/CdS films were fabricated, and their performance parameters were evaluated under 365 nm light illumination. Our findings demonstrated that reducing CdS layer thickness enhanced performance concerning detectivity, responsivity, external quantum efficiency (EQE), and photocurrent gain. Furthermore, AuNP deposition on the surface of CdS films exhibited a substantial influence, especially on devices with thinner CdS layers. Among the configurations, AuNPs/CdS(100 nm) demonstrated the highest values in all evaluated parameters, including detectivity (

1.1 \times 10^{12}

Jones), responsivity (13.86 A/W), EQE (47.2%), and photocurrent gain (9.2). Full article

(This article belongs to the Special Issue Advanced Research on Low-Dimensional Optoelectronic Nanomaterials and Nanodevices)

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16 pages, 5037 KiB

Open AccessArticle

Bicarbazole-Benzophenone-Based Twisted Donor-Acceptor-Donor Derivatives as Blue Emitters for Highly Efficient Fluorescent Organic Light-Emitting Diodes

by Dovydas Blazevicius, Iram Siddiqui, Prakalp Gautam, Gintare Krucaite, Daiva Tavgeniene, Mangey Ram Nagar, Krishan Kumar, Subrata Banik, Jwo-Huei Jou and Saulius Grigalevicius

Nanomaterials 2024, 14(2), 146; https://doi.org/10.3390/nano14020146 - 9 Jan 2024

Cited by 4 | Viewed by 1864

Abstract

This paper delves into the development of a group of twisted donor-acceptor-donor (D-A-D) derivatives incorporating bicarbazole as electron donor and benzophenone as electron acceptor for potential use as blue emitters in OLEDs. The derivatives were synthesized in a reaction of 4,4′-difluorobenzophenone with various [...] Read more.

This paper delves into the development of a group of twisted donor-acceptor-donor (D-A-D) derivatives incorporating bicarbazole as electron donor and benzophenone as electron acceptor for potential use as blue emitters in OLEDs. The derivatives were synthesized in a reaction of 4,4′-difluorobenzophenone with various 9-alkyl-9′H-3,3′-bicarbazoles. The materials, namely, DB14, DB23, and DB29, were designed with different alkyl side chains to enhance their solubility and film-forming properties of layers formed using the spin-coating from solution method. The new materials demonstrate high thermal stabilities with decomposition temperatures >383 °C, glass transition temperatures in the range of 95–145 °C, high blue photoluminescence quantum yields (>52%), and short decay times, which range in nanoseconds. Due to their characteristics, the derivatives were used as blue emitters in OLED devices. Some of the OLEDs incorporating the DB23 emitter demonstrated a high external quantum efficiency (EQE_max) of 5.3%, which is very similar to the theoretical limit of the first-generation devices. Full article

(This article belongs to the Special Issue Advanced Research on Low-Dimensional Optoelectronic Nanomaterials and Nanodevices)

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Review

Jump to: Research

35 pages, 1758 KiB

Open AccessFeature PaperReview

A Review of Benzophenone-Based Derivatives for Organic Light-Emitting Diodes

by Dovydas Blazevicius and Saulius Grigalevicius

Nanomaterials 2024, 14(4), 356; https://doi.org/10.3390/nano14040356 - 14 Feb 2024

Cited by 6 | Viewed by 2931

Abstract

Organic light-emitting diodes (OLEDs) have garnered considerable attention in academic and industrial circles due to their potential applications in flat-panel displays and solid-state lighting technologies, leveraging the advantages offered by organic electroactive derivatives over their inorganic counterparts. The thin and flexible design of [...] Read more.

Organic light-emitting diodes (OLEDs) have garnered considerable attention in academic and industrial circles due to their potential applications in flat-panel displays and solid-state lighting technologies, leveraging the advantages offered by organic electroactive derivatives over their inorganic counterparts. The thin and flexible design of OLEDs enables the development of innovative lighting solutions, facilitating the creation of customizable and contoured lighting panels. Among the diverse electroactive components employed in the molecular design of OLED materials, the benzophenone core has attracted much attention as a fragment for the synthesis of organic semiconductors. On the other hand, benzophenone also functions as a classical phosphor with high intersystem crossing efficiency. This characteristic makes it a compelling candidate for effective reverse intersystem crossing, with potential in leading to the development of thermally activated delayed fluorescent (TADF) emitters. These emitting materials witnessed a pronounced interest in recent years due to their incorporation in metal-free electroactive frameworks and the capability to convert triplet excitons into emissive singlet excitons through reverse intersystem crossing (RISC), consequently achieving exceptionally high external quantum efficiencies (EQEs). This review article comprehensively overviews the synthetic pathways, thermal characteristics, electrochemical behaviour, and photophysical properties of derivatives based on benzophenone. Furthermore, we explore their applications in OLED devices, both as host materials and emitters, shedding light on the promising opportunities that benzophenone-based compounds present in advancing OLED technology. Full article

(This article belongs to the Special Issue Advanced Research on Low-Dimensional Optoelectronic Nanomaterials and Nanodevices)

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