Investigating sensing properties of poly-(dioctylfluorene) based planar sensor

Rehman, Fazal; Tahir, Muḥammad; Hameed, Sardar; Wahab, Fazal; Khan, Dil Nawaz; Aziz, Fakhra; Khalid, Fazal Ahmad; Khalid, Muhammad; Ali, Wajid

doi:10.1016/j.mssp.2015.04.046

Cited by 14 publications

(4 citation statements)

References 38 publications

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“…These voids are believed to play critical role in adsorbing water vapors. 20 At higher magnication, 12k (see Fig. 5(b)), the average size of the microstructures can be easily estimated.…”

Section: Resultsmentioning

confidence: 99%

Humidity sensor based on electrospun MEH-PPV:PVP microstructured composite

et al. 2016

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Section: Resultsmentioning

confidence: 99%

Humidity sensor based on electrospun MEH-PPV:PVP microstructured composite

et al. 2016

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“…Among organic semiconductors, conducting polymers are famous for their potential use in electronics, optoelectronics, and sensors. Polyfluorenes and its derivatives belong to a class of polymeric semiconductors that demonstrate comparatively higher charge carriers mobility as well as good chemical, mechanical and thermal stability [8]. Poly(9,9dioctylfluorene) (F8) is a semiconducting polymer with the unique characteristics such as its solubility in several solvents, good π-conjugation structure with high hole mobility, large photoluminescence quantum efficiency, stability at higher humidity levels, and strongly hydrophobic behavior.…”

Section: Introductionmentioning

confidence: 99%

“…The materials showing the variations in dielectric constant, being used for capacitive-type sensors, while in the resistive type, the electrical resistance of polymers decreases with the absorbing water molecules [4]. The capacitive technique is considered as the most favorable for miniaturized humidity sensors [8,34,35].…”

Section: Introductionmentioning

confidence: 99%

Cuprous Oxide Nanoparticles: Synthesis, Characterization, and Their Application for Enhancing the Humidity-Sensing Properties of Poly(dioctylfluorene)

et al. 2022

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In this paper, we report on the synthesis—via the wet chemical precipitation route method—and thin film characteristics of inorganic semiconductor, cuprous oxide (Cu2O) nanoparticles, for their potential application in enhancing the humidity-sensing properties of semiconducting polymer poly(9,9-dioctylfluorene) (F8). For morphological analysis of the synthesized Cu2O nanoparticles, transmission electron microscope (TEM) and scanning electron microscope (SEM) micrographs are studied to investigate the texture, distribution, shape, and sizes of Cu2O crystallites. The TEM image of the Cu2O nanoparticles exhibits somewhat non-uniform distribution with almost uniform shape and size having an average particle size of ≈24 ± 2 nm. Fourier transformed infrared (FTIR) and X-ray diffraction (XRD) spectra are studied to validate the formation of Cu2O nanoparticles. Additionally, atomic force microscopy (AFM) is performed to analyze the surface morphology of polymer-inorganic (F8-Cu2O) nanocomposites thin film to see the grain sizes, mosaics, and average surface roughness. In order to study the enhancement in sensing properties of F8, a hybrid organic–inorganic (F8-Cu2O) surface-type humidity sensor Ag/F8-Cu2O/Ag is fabricated by employing F8 polymer as an active matrix layer and Cu2O nanoparticles as a dopant. The Ag/F8-Cu2O/Ag device is prepared by spin coating a 10:1 wt% solution of F8-Cu2O nanocomposite on pre-patterned silver (Ag) electrodes on glass. The inter-electrode gap (≈5 μm) between Ag is developed by photolithography. To study humidity sensing, the Ag/F8-Cu2O/Ag device is characterized by measuring its capacitance (C) as a function of relative humidity (%RH) at two different frequencies (120 Hz and 1 kHz). The device exhibits a broad humidity sensing range (27–86%RH) with shorter response time and recovery time, i.e., 9 s and 8 s, respectively. The present results show significant enhancement in the humidity-sensing properties as compared to our previously reported results of Ag/F8/Ag sensor wherein the humidity sensing range was 45–78%RH with 15 s and 7 s response and recovery times, respectively. The improvement in the humidity-sensing properties is attributed to the potential use of Cu2O nanoparticles, which change the hydrophobicity, surface to volume ratio of Cu2O nanoparticles, as well as modification in electron polarizability and polarity of the F8 matrix layer.

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“…Response time for capacitive/resistive sensor is defined as the time taken by the sensor to absorb water vapours when the relative-humidity is increased rapidly and recovery time is the time taken by the sensor to recover itself to its initial state by desorbing water vapours with rapid decrease in humidity. The time, the sensor required to reach its final value before saturation, was recorded as the response time and vice versa for recovery time [25]. (1) Figure 5 shows the band gap of the thin film by tracing the linear portion of the graph plotted between (αhυ) 2 eV 2 cm -2 and energy (hυ) eV.…”

Section: Setup For Measuring Sensing Propertiesmentioning

confidence: 99%

Capacitive and resistive response of humidity sensors based on graphene decorated by PMMA and silver nanoparticles

Rahim

Shah

Khan

et al. 2018

Sensors and Actuators B: Chemical

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In this paper, we reported comparative study of the humidity characteristics of graphene/silver nanoparticles composite (Gr-AgNps) and graphene/silver nanoparticles/PMMA composite (Gr-AgNps-PMMA) based efficient humidity sensors. Aqueous solution of Gr-AgNps and Gr-AgNps-PMMA was drop casted over interdigitated copper electrodes with 50 µm gap embedded in the substrates in dust free environment. The band gap obtained from the UV-vis spectra for Gr-AgNps and Gr-AgNps-PMMA based humidity sensors was 4.7 and 4.1 eV respectively. The capacitive and resistive humidity response was studied using LCR meter (GW Instek817). Apparent increase in capacitance was observed (100-10,000 nF) with the increase in the humidity percentage (30-95 %RH) at lower frequencies for both the sensors. Resistance of the sensors dropped to zero as the humidity level is increased from 30 to 95 %RH in the chamber. The devices were tested for real time stability and for fast response/recovery time. Both the devices showed an excellent stability and response by recording their resistance and capacitance respectively. A lagging of RH decreasing response from RH increasing response was observed at 500 Hz frequency for both the sensors depicted from the hysteresis curve. The humidity response of Gr-AgNps was comparatively better than that of the Gr-AgNps-PMMA based humidity sensors.

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Investigating sensing properties of poly-(dioctylfluorene) based planar sensor

Cited by 14 publications

References 38 publications

Humidity sensor based on electrospun MEH-PPV:PVP microstructured composite

Humidity sensor based on electrospun MEH-PPV:PVP microstructured composite

Cuprous Oxide Nanoparticles: Synthesis, Characterization, and Their Application for Enhancing the Humidity-Sensing Properties of Poly(dioctylfluorene)

Capacitive and resistive response of humidity sensors based on graphene decorated by PMMA and silver nanoparticles

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