Copper (II) Phthalocyanine based Organic Field-Effect Transistors for UV Photo-detection
01 Mar 2019-
TL;DR: In this paper, the effect of UV irradiation on the electrical performance of OFETs with CuPc as active layer is demonstrated, and the devices have shown stable electrical performance under dark with avg. and max. field effect mobility of $( 1.0 \pm 0.3 ) \times 10 ^{-2}$ and $1.4 \times 6.5 cm $ 2
Abstract: Effect of UV irradiation $( \lambda _{Peak} \quad =365$ nm) on the electrical performance of the OFETs with CuPc as active layer is demonstrated. The devices have shown stable electrical performance under dark with avg. and max. field effect mobility of $( 1.0 \pm 0.3 ) \times 10 ^{-2}$ and $1.4 \times 10 ^{-2}$ cm $^{2}\, \mathrm {V}^{-1}\, \mathrm {s}^{-1}$ respectively. Under UV illumination there found a shift in threshold voltage and change in ON current along with fast response and recovery time of 0.4 s and 2 s respectively with periodic UV ON-OFF pulses.
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26 Sep 2022
TL;DR: In this article , the temporal evolution of the photogenerated charge in organic field effect transistors was investigated and the gatevoltage dependence was used to distinguish the driving force.
Abstract: The charge photogeneration phenomenon in organic semiconducting materials gains great interest due to its application in organic solar cells or photosensitive devices. Here we report the temporal evolution of the photogenerated charge in organic field-effect transistors. Since the charge transfer can be ruled by the drift or diffusion processes, the gate-voltage dependence is used to distinguish the driving force.
References
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TL;DR: In this paper, a high performance OFET with pentacene and copper phthalocyanine (CuPC) was fabricated from organic phototransistors (OPTs) based on the geometry of organic field effect transistors (OFETs); and the effect of the wavelength of the incident light source on their performance was examined.
Abstract: Organic phototransistors (OPTs) were fabricated from pentacene and copper phthalocyanine (CuPC) based on the geometry of organic field-effect transistors (OFETs); and the effect of the wavelength of the incident light source on their performance was examined High performance OFETs with pentacene and CuPC were fabricated and the characteristics of the OPTs were examined under UV and visible-light irradiations with top illumination The CuPC and pentacene OPTs show a high responsivities of 05–2 and 10–50A∕W and maximum IPh∕IDark of 3000 and 13×105, respectively, under 365nm UV light However, under visible light, at a wavelength of 650nm, the pentacene OPTs had 100 times less responsivity, 015–045A∕W, and a IPh∕IDark of 1000, even though an absorption coefficient three times larger was observed at this wavelength than at 365nm A strong correlation was found between the performance of the OPTs and the incident photon to current conversion efficiency spectra of an organic semiconductor The strong depen
194 citations
TL;DR: These bar-coated ultrathin films are capable of realizing highly sensitive multigas sensors and represent the first successful report of ethylene detection using a sensor based on organic field-effect transistors.
Abstract: A uniform ultrathin polymer film is deposited over a large area with molecularlevel precision by the simple wire-wound bar-coating method. The bar-coated ultrathin films not only exhibit high transparency of up to 90% in the visible wavelength range but also high charge carrier mobility with a high degree of percolation through the uniformly covered polymer nanofibrils. They are capable of realizing highly sensitive multigas sensors and represent the first successful report of ethylene detection using a sensor based on organic field-effect transistors.
173 citations
"Copper (II) Phthalocyanine based Or..." refers background in this paper
...Though organic semiconductor materials offer lower charge carrier mobility compared to their inorganic counterpart, OFETs have been explored for various applications such as gas sensor, chemical sensor, biological sensor, humidity sensor etc.[1, 2, 5]; because of their higher sensitivity, ease of processing, and mechanical flexibility [6]....
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...(Keywords: Photo-sensitive OFETs, CuPc, UV Irradiation) Introduction Organic field-effect transistors (OFETs) are considered as promising candidate for the next generation sensing and circuit application [1-4]....
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TL;DR: In this paper, highly photosensitive organic phototransistors (OPTs) based on a 2,5-bis-biphenyl-4-yl-thieno[3,2-b]thiophene (BPTT) were reported.
Abstract: We report highly photosensitive organic phototransistors (OPTs) based on a 2,5-bis-biphenyl-4-yl-thieno[3,2-b]thiophene (BPTT). The measured maximum sensitivity and the ratio of photocurrent to dark current (Iph∕Idark) in BPTT OPTs were 82A∕W and 2.0×105 under 380nm UV light with 1.55mW∕cm2, respectively. The prepared OPTs show a photocurrent response similar to the absorption spectrum of BPTT. The major mechanisms for photocurrent amplification in this device were verified from experimental results as photovoltaic (turn-on) and photocurrent effect (turn-off) by a fitting to theoretic equations.
169 citations
"Copper (II) Phthalocyanine based Or..." refers background in this paper
...In addition, organic semiconductor materials have been explored for various light-sensing devices such as photo-diode, light emitting diode, photo-transistors, photocontrolled switches, and electronic memory elements; because of their wider absorption spectra in the UV-Vis spectrum and higher photo-responsivity towards light stimulus [7, 8]....
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TL;DR: In this article, an optimized composition of 1.6% poly(3-hexylthiophene) (P3HT) blended with polystyrene (PS) as a semiconductor layer were fabricated.
Abstract: Ammonia (NH 3 ) gas sensors based on organic field-effect transistor (OFET) using poly(3-hexylthiophene) (P3HT) blended with polystyrene (PS) as a semiconductor layer were fabricated. An optimized composition of 1.6 wt% P3HT in PS matrix exhibited the best performance to various concentrations of NH 3 , which is comparable to that of pure P3HT (8 wt%). The results showed the percentage responses of saturation current were 52% and 16% under 50 ppm and 5 ppm NH 3 , respectively. Also, it showed that there was a remarkable shift in the field-effect mobility after exposed to NH 3 gas. By analyzing the morphologies of blend films and the electrical characteristics of OFET sensors, it was found that the film of P3HT blended with PS has more interface to interact with NH 3 , resulting in more efficient detection to NH 3 even in the range of low concentration. Besides, the PS matrix would prevent the gas from diffusing into the semiconductor/dielectric interface directly, which was beneficial to the selectivity of P3HT/PS blend OFET sensor. Moreover, the sensing property was related to the solvents and molecular weight of PS. In addition, the environmental stability of OFET sensors was measured after storing the sensors under ambient atmosphere for 40 days, and the device with the blend semiconducting layer exhibited the superior stability.
159 citations
"Copper (II) Phthalocyanine based Or..." refers background in this paper
...Though organic semiconductor materials offer lower charge carrier mobility compared to their inorganic counterpart, OFETs have been explored for various applications such as gas sensor, chemical sensor, biological sensor, humidity sensor etc.[1, 2, 5]; because of their higher sensitivity, ease of processing, and mechanical flexibility [6]....
[...]
...(Keywords: Photo-sensitive OFETs, CuPc, UV Irradiation) Introduction Organic field-effect transistors (OFETs) are considered as promising candidate for the next generation sensing and circuit application [1-4]....
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TL;DR: In this article, the optical absorption of thermally evaporated copper phthalocyanine (CuPc) was studied in the UV-VIS-NIR region and the spectral properties such as the molar extinction coefficient (e molar ), the oscillator strength ( f), the electric dipole strength ( q 2 ) and absorption half-bandwidth (Δ λ ) of the principle optical transitions were evaluated.
Abstract: The optical absorption of thermally evaporated copper phthalocyanine (CuPc) was studied in the UV-VIS-NIR region. The absorption spectra recorded in the UV-VIS region show two well-defined absorption bands of the phthalocyanine molecules, namely, the Soret ( B ) and the Q -band . The Q -band shows its characteristic splitting (Davydov splitting) of the main absorption peak in the metal phthalocyanine correlates with the relative tendencies of the metal to out-of-plane bonding. Some of the important spectral characteristics such as the molar extinction coefficient (e molar ), the oscillator strength ( f) , the electric dipole strength ( q 2 ) and absorption half-bandwidth (Δ λ ) of the principle optical transitions were evaluated. The analysis of the spectral behavior of the absorption coefficient α in the absorption region revealed two indirect allowed transitions with corresponding energies 2.95±0.03 and 1.55±0.02 eV. The spectra of the infrared absorption allow characterization of vibration modes for the powder, as-deposited material and thin films of CuPc annealed at 423 K for two hours. Discussion of the obtained results and their comparison with the previous published data are also given.
99 citations
"Copper (II) Phthalocyanine based Or..." refers background in this paper
...CuPc thin film is known to exhibit absorption in UV region (B-band) due to π-d interaction in CuPc molecule [11]....
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