Vapor-Phase Amine Intercalation for the Rational Design of Photonic Nanosheet Sensors

The development of vapor sensors with tunable sensitivity and selectivity is highly desirable because of the manifold applications ranging from air quality monitoring to food control. The design of such sensors remains, however, a great challenge. Here, we address this challenge by intercalating primary and tertiary alkylamines with varying alkyl chain lengths into H₃Sb₃P₂O₁₄ nanosheet-based Fabry-Pérot interference sensors. As the sensors are photonic in nature, the different amines can be distinguished based on their intercalation time and optical shift. Since the amines are protonated during intercalation and therefore trapped, this allows us to use amine modification as the basis for creating optical sensors. Intercalation of different amines gradually and widely tunes the sensor’s sensitivity and selectivity to various analytes. This adjustment of sensing properties allows us to construct a sensor array on a single chip, which can distinguish different volatile organic compounds. The color change of this sensor array upon exposure to solvent vapors can be tracked with the naked eye, making this system a promising platform for the high-fidelity identification of volatile compounds. The sensor design protocol presented herein is straightforward and robust and can be transferred to other nanosheet-based devices for the rational tuning of their vapor-sensing properties and beyond

Vapor-Phase Amine Intercalation for the Rational Design of Photonic Nanosheet Sensors

The development of vapor sensors with tunable sensitivity and selectivity is highly desirable because of the manifold applications ranging from air quality monitoring to food control. The design of such sensors remains, however, a great challenge. Here, we address this challenge by intercalating primary and tertiary alkylamines with varying alkyl chain lengths into H₃Sb₃P₂O₁₄ nanosheet-based Fabry-Pérot interference sensors. As the sensors are photonic in nature, the different amines can be distinguished based on their intercalation time and optical shift. Since the amines are protonated during intercalation and therefore trapped, this allows us to use amine modification as the basis for creating optical sensors. Intercalation of different amines gradually and widely tunes the sensor’s sensitivity and selectivity to various analytes. This adjustment of sensing properties allows us to construct a sensor array on a single chip, which can distinguish different volatile organic compounds. The color change of this sensor array upon exposure to solvent vapors can be tracked with the naked eye, making this system a promising platform for the high-fidelity identification of volatile compounds. The sensor design protocol presented herein is straightforward and robust and can be transferred to other nanosheet-based devices for the rational tuning of their vapor-sensing properties and beyond

Analyte Detection with Cu-BTC Metal–Organic Framework Thin Films by Means of Mass-Sensitive and Work-Function-Based Readout

Metal–organic frameworks (MOFs) constitute a new generation of porous crystalline materials, which have recently come into focus as analyte-specific active elements in thin-film sensor devices. Cu-BTCalso known as HKUST-1is one of the most theoretically and experimentally investigated members of the MOF family. Its capability to selectively adsorb different gas molecules renders this material a promising candidate for applications in chemical gas and vapor sensing. Here, we explore details of the host–guest interactions between HKUST-1 and various analytes under different environmental conditions and study the vapor adsorption mechanism by mass-sensitive and work-function-based readouts. These complementary transduction mechanisms were successfully applied for the detection of low ppm (2 to 50 ppm) concentrations of different alcohols (methanol, ethanol, 1-propanol, and 2-propanol) adsorbed into Cu-BTC thin films. Evaluation of the results allows for the comparison of the amounts of adsorbed vapors and the contribution of each vapor to the changes of the electronic properties of Cu-BTC. The influence of the length of the alcohol chain (C1–C3) and geometry (1-propanol, 2-propanol) as well as their polarity on the sensing performance was investigated, revealing that in dry air, short chain alcohols are more likely adsorbed than long chain alcohols, whereas in humid air, this preference is changed, and the sensitivity toward alcohols is generally decreased. The adsorption mechanism is revealed to differ for dry and humid atmospheres, changing from a site-specific binding of alcohols to the open metal sites under dry conditions to weak physisorption of the analytes dissolved in surface-adsorbed water reservoirs in humid air, with the signal strength being governed by their relative concentration

Vapor-Phase Amine Intercalation for the Rational Design of Photonic Nanosheet Sensors

The development of vapor sensors with tunable sensitivity and selectivity is highly desirable because of the manifold applications ranging from air quality monitoring to food control. The design of such sensors remains, however, a great challenge. Here, we address this challenge by intercalating primary and tertiary alkylamines with varying alkyl chain lengths into H₃Sb₃P₂O₁₄ nanosheet-based Fabry-Pérot interference sensors. As the sensors are photonic in nature, the different amines can be distinguished based on their intercalation time and optical shift. Since the amines are protonated during intercalation and therefore trapped, this allows us to use amine modification as the basis for creating optical sensors. Intercalation of different amines gradually and widely tunes the sensor’s sensitivity and selectivity to various analytes. This adjustment of sensing properties allows us to construct a sensor array on a single chip, which can distinguish different volatile organic compounds. The color change of this sensor array upon exposure to solvent vapors can be tracked with the naked eye, making this system a promising platform for the high-fidelity identification of volatile compounds. The sensor design protocol presented herein is straightforward and robust and can be transferred to other nanosheet-based devices for the rational tuning of their vapor-sensing properties and beyond

Vapor-Phase Amine Intercalation for the Rational Design of Photonic Nanosheet Sensors

The development of vapor sensors with tunable sensitivity and selectivity is highly desirable because of the manifold applications ranging from air quality monitoring to food control. The design of such sensors remains, however, a great challenge. Here, we address this challenge by intercalating primary and tertiary alkylamines with varying alkyl chain lengths into H₃Sb₃P₂O₁₄ nanosheet-based Fabry-Pérot interference sensors. As the sensors are photonic in nature, the different amines can be distinguished based on their intercalation time and optical shift. Since the amines are protonated during intercalation and therefore trapped, this allows us to use amine modification as the basis for creating optical sensors. Intercalation of different amines gradually and widely tunes the sensor’s sensitivity and selectivity to various analytes. This adjustment of sensing properties allows us to construct a sensor array on a single chip, which can distinguish different volatile organic compounds. The color change of this sensor array upon exposure to solvent vapors can be tracked with the naked eye, making this system a promising platform for the high-fidelity identification of volatile compounds. The sensor design protocol presented herein is straightforward and robust and can be transferred to other nanosheet-based devices for the rational tuning of their vapor-sensing properties and beyond

Vapor-Phase Amine Intercalation for the Rational Design of Photonic Nanosheet Sensors

The development of vapor sensors with tunable sensitivity and selectivity is highly desirable because of the manifold applications ranging from air quality monitoring to food control. The design of such sensors remains, however, a great challenge. Here, we address this challenge by intercalating primary and tertiary alkylamines with varying alkyl chain lengths into H₃Sb₃P₂O₁₄ nanosheet-based Fabry-Pérot interference sensors. As the sensors are photonic in nature, the different amines can be distinguished based on their intercalation time and optical shift. Since the amines are protonated during intercalation and therefore trapped, this allows us to use amine modification as the basis for creating optical sensors. Intercalation of different amines gradually and widely tunes the sensor’s sensitivity and selectivity to various analytes. This adjustment of sensing properties allows us to construct a sensor array on a single chip, which can distinguish different volatile organic compounds. The color change of this sensor array upon exposure to solvent vapors can be tracked with the naked eye, making this system a promising platform for the high-fidelity identification of volatile compounds. The sensor design protocol presented herein is straightforward and robust and can be transferred to other nanosheet-based devices for the rational tuning of their vapor-sensing properties and beyond

Vapor-Phase Amine Intercalation for the Rational Design of Photonic Nanosheet Sensors

The development of vapor sensors with tunable sensitivity and selectivity is highly desirable because of the manifold applications ranging from air quality monitoring to food control. The design of such sensors remains, however, a great challenge. Here, we address this challenge by intercalating primary and tertiary alkylamines with varying alkyl chain lengths into H₃Sb₃P₂O₁₄ nanosheet-based Fabry-Pérot interference sensors. As the sensors are photonic in nature, the different amines can be distinguished based on their intercalation time and optical shift. Since the amines are protonated during intercalation and therefore trapped, this allows us to use amine modification as the basis for creating optical sensors. Intercalation of different amines gradually and widely tunes the sensor’s sensitivity and selectivity to various analytes. This adjustment of sensing properties allows us to construct a sensor array on a single chip, which can distinguish different volatile organic compounds. The color change of this sensor array upon exposure to solvent vapors can be tracked with the naked eye, making this system a promising platform for the high-fidelity identification of volatile compounds. The sensor design protocol presented herein is straightforward and robust and can be transferred to other nanosheet-based devices for the rational tuning of their vapor-sensing properties and beyond

Vapor-Phase Amine Intercalation for the Rational Design of Photonic Nanosheet Sensors

The development of vapor sensors with tunable sensitivity and selectivity is highly desirable because of the manifold applications ranging from air quality monitoring to food control. The design of such sensors remains, however, a great challenge. Here, we address this challenge by intercalating primary and tertiary alkylamines with varying alkyl chain lengths into H₃Sb₃P₂O₁₄ nanosheet-based Fabry-Pérot interference sensors. As the sensors are photonic in nature, the different amines can be distinguished based on their intercalation time and optical shift. Since the amines are protonated during intercalation and therefore trapped, this allows us to use amine modification as the basis for creating optical sensors. Intercalation of different amines gradually and widely tunes the sensor’s sensitivity and selectivity to various analytes. This adjustment of sensing properties allows us to construct a sensor array on a single chip, which can distinguish different volatile organic compounds. The color change of this sensor array upon exposure to solvent vapors can be tracked with the naked eye, making this system a promising platform for the high-fidelity identification of volatile compounds. The sensor design protocol presented herein is straightforward and robust and can be transferred to other nanosheet-based devices for the rational tuning of their vapor-sensing properties and beyond

Tandem MOF-Based Photonic Crystals for Enhanced Analyte-Specific Optical Detection

Owing to their structural variability, metal–organic frameworks (MOFs) lend themselves well as chemical sensing materials by providing both high sensitivity and selectivity. Here, we integrate different types of MOFs (ZIF-8, HKUST-1, CAU-1-NH₂) into photonic multilayers referred to as Bragg stacks (BSs), which report on adsorption events through changes in their effective refractive index (RI). The fabrication of photonic multilayers is accomplished by spin-coating colloidal suspensions of MOF nanoparticles and/or the high RI-material TiO₂. While their incorporation in BSs allows for the label-free readout of host–guest interactions, the choice of particular types of MOFs determines the sensing properties of the BS. Here, we present MOF-based BSs with enhanced specificity toward molecular analytes by combining two different MOFs in a single platform. The sensing performance of our BSs is demonstrated by a combined spectroscopic and principal component analysis of their vapor response. Time-dependent measurements reveal fast response times and good recoverability of the multilayers. Moreover, we demonstrate that combinatorial sensing is feasible by arranging different MOF BSs in a basic color pattern, which highlights the potential of MOF-based multilayers in arrayed sensor devices

Facile Fabrication of Ultrathin Metal–Organic Framework-Coated Monolayer Colloidal Crystals for Highly Efficient Vapor Sensing

The sorption properties and structural versatility of metal–organic frameworks (MOFs) make them superior chemical sensing materials with both high sensitivity and selectivity, but the fabrication of MOF sensors with optimized performances still remains a major challenge. Herein, we propose a simple yet powerful optical sensing motif based on ultrathin MOF-coated monolayer colloidal crystals (MCCs), which allows for high efficiency in vapor sensing through changes in their effective refractive index (RI). Two optical modes exist in this sensor, namely, photonic eigenmodes and Fabry–Pérot oscillations, both of which can be used as the signal transducer. Selective response to a series of alcohols, water, and acetonitrile was exhibited, reflecting well the characteristic sorption properties of the integrated MOF, with which colorimetric reporting was readily achieved. Linear response to a broad dynamic range of vapor concentration was realized. The sensitivity was found to depend closely on the thickness of the MOF coating and can be further enhanced accordingly. Ultrafast response time (<5 s) and excellent recyclability were also demonstrated. These substantial improvements in performance are attributed to the efficacy of signal transduction and the enhanced pore accessibility and diffusion efficiency, which are intrinsically endowed by the optical motif design. Our findings should provide new insights into the design and fabrication of MOF sensors toward real-world applications