Ultraviolet light response of electrical and dielectric properties in zinc phthalocyanine and fullerene dispersed liquid crystal composites

2015 ◽  
Vol 93 (10) ◽  
pp. 1207-1212 ◽  
Author(s):  
O. Köysal ◽  
M. Gökçen ◽  
M. Yıldırım
Keyword(s):  
Liquid Crystal ◽  
Indium Tin Oxide ◽  
Uv Light ◽  
Light Response ◽  
Research Area ◽  
Open Circuit ◽  
Zinc Phthalocyanine ◽  
Dielectric Anisotropy ◽  
Photovoltaic Properties ◽  
Power Intensity

Liquid crystal composites form an attractive research area in liquid crystal studies. Among these composites, nematic liquid crystal composited E63 is of particular interest. In the present study, E63 coded liquid crystal composites were dispersed with zinc phthalocyanine (Zn-Pc) and fullerene (C60), and three samples were prepared as E63, E63/Zn-Pc, and E63/Zn-Pc/C60 in indium tin oxide coated cells via capillary action. Later, current and capacitance measurements of the samples were carried out in darkness and under ultraviolet (UV) illumination (365 nm) of 100 mW/cm2 power intensity. It was found that both current and capacitance in the samples are affected by UV light and dispersal of Zn-Pc and C60. Particularly, dispersal of Zn-Pc led to occurrence of photovoltaic properties, which yielded open-circuit voltage of 0.37 V for the E63/Zn-Pc sample. Furthermore, dielectric constant and dielectric anisotropy values were extracted from capacitance values, and UV light was seen to increase the transition frequency of dielectric anisotropy slightly for all samples.

scholarly journals Fabrication and Photovoltaic Properties of Organic Solar Cell Based on Zinc Phthalocyanine

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 962 ◽  
Author(s):  
Zahoor Ul Islam ◽  
Muhammad Tahir ◽  
Waqar Adil Syed ◽  
Fakhra Aziz ◽  
Fazal Wahab ◽  
...  
Keyword(s):  
Thin Films ◽  
Thick Film ◽  
Indium Tin Oxide ◽  
Hole Transport ◽  
Transport Layer ◽  
Zinc Phthalocyanine ◽  
Hole Transport Layer ◽  
Interfacial Resistance ◽  
Ito Cell ◽  
Photovoltaic Properties

Herein, we report thin films’ characterizations and photovoltaic properties of an organic semiconductor zinc phthalocyanine (ZnPc). To study the former, a 100 nm thick film of ZnPc is thermally deposited on quartz glass by using vacuum thermal evaporator at 1.5 × 10−6 mbar. Surface features of the ZnPc film are studied by using scanning electron microscope (SEM) with in situ energy dispersive x-ray spectroscopy (EDS) analysis and atomic force microscope (AFM) which reveal uniform film growth, grain sizes and shapes with slight random distribution of the grains. Ultraviolet-visible (UV-vis) and Fourier Transform Infrared (FTIR) spectroscopies are carried out of the ZnPc thin films to measure its optical bandgap (1.55 eV and 3.08 eV) as well as to study chemical composition and bond-dynamics. To explore photovoltaic properties of ZnPc, an Ag/ZnPc/PEDOT:PSS/ITO cell is fabricated by spin coating a 20 nm thick film of hole transport layer (HTL)—poly-(3,4-ethylenedioxythiophene) poly(styrene sulfonic acid) (PEDOT:PSS)—on indium tin oxide (ITO) substrate followed by thermal evaporation of a 100 nm layer of ZnPc and 50 nm silver (Ag) electrode. Current-voltage (I-V) properties of the fabricated device are measured in dark as well as under illumination at standard testing conditions (STC), i.e., 300 K, 100 mW/cm2 and 1.5 AM global by using solar simulator. The key device parameters such as ideality factor (n), barrier height ( ϕ b ), junction/interfacial resistance (Rs) and forward current rectification of the device are measured in the dark which exhibit the formation of depletion region. The Ag/ZnPc/PEDOT:PSS/ITO device demonstrates good photovoltaic characteristics by offering 0.48 fill factor (FF) and 1.28 ± 0.05% power conversion efficiency (PCE), η.

Photovoltaic properties of ITO/p-Si heterojunction prepared by pulsed laser deposition

2020 ◽  
Vol 34 (32) ◽  
pp. 2050321
Author(s):  
Raid A. Ismail ◽  
Omar A. Abdulrazzaq ◽  
Abdullah M. Ali
Keyword(s):  
Pulsed Laser Deposition ◽  
Indium Tin Oxide ◽  
Open Circuit Voltage ◽  
Energy Gap ◽  
Short Circuit ◽  
Pulsed Laser ◽  
Open Circuit ◽  
Laser Deposition ◽  
Optical Energy Gap ◽  
Photovoltaic Properties

In this study, indium tin oxide (ITO) was deposited onto sapphire and low resistive p-Si substrates using pulsed laser deposition (PLD) technique. The optical energy gap of ITO deposited on the sapphire substrate was 3.7 eV at room temperature. Photoluminescence (PL) of ITO shows an emission of broad peak at 524 nm. Photovoltaic (PV) characteristics of the n-ITO/p-Si heterojunction are examined and showed conversion efficiency [Formula: see text] of 1.8%. The open circuit voltage [Formula: see text] for this cell was 0.49 V while the short circuit current density [Formula: see text] was 17.4 mA/cm2. The fill factor of this cell was 22%. The ideality factor of ITO/Si heterojunction is about 3.1. The barrier height [Formula: see text] of the heterojunction was determined from I–V characteristics and was 0.83 eV. The responsivity of the heterojunction was measured and the maximum value of responsivity was 0.5 A/W without bias voltage. The minority carrier lifetime of the solar was measured using open circuit voltage decay (OCVD) method and found to be 227 [Formula: see text]s.

Orientation of Ferroelectric Liquid Crystals by Self-Assembled Bilayer Molecular Assembly

2001 ◽  
Vol 709 ◽  
Author(s):  
Sukhmal C. Jain ◽  
Vivechana Dixit ◽  
Vinod K. Tanwar ◽  
S. M. Shivaprasad
Keyword(s):  
Liquid Crystal ◽  
Indium Tin Oxide ◽  
Photoelectron Spectroscopy ◽  
Self Assembly ◽  
Uv Light ◽  
Uv Spectroscopy ◽  
Large Change ◽  
Molecular Assembly ◽  
Ferroelectric Liquid Crystal ◽  
Assembly Technique

ABSTRACTMolecular films of amino propyl triethoxy silane (APTES) attached with cinnamoyl moieties were deposited on indium tin oxide (ITO) coated glass and quartz substrates by self-assembly technique. The deposition of the monolayer films resulted in a large change in the wettability of the substrates. X-ray photoelectron spectroscopy (XPS) and UV-spectroscopy were used to study the structure and properties of the grown films. The molecular assembly was photodimerized by irradiating it with a linearly polarized UV-light. Thus created polymer-solid interface has been shown to produce good, stable planar orientation of ferroelectric liquid crystal mixtures. The electro-optical and switching properties of the ferroelectric liquid crystal cells have been investigated and found to be quite similar to those prepared in conventional manner.

scholarly journals Thickness Optimization and Photovoltaic Properties of Bulk Heterojunction Solar Cells Based on PFB–PCBM Layer

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5915
Author(s):  
Sayed Izaz Uddin ◽  
Muhammad Tahir ◽  
Fakhra Aziz ◽  
Mahidur R. Sarker ◽  
Fida Muhammad ◽  
...  
Keyword(s):  
Solar Cells ◽  
Indium Tin Oxide ◽  
Bulk Heterojunction ◽  
Acid Methyl Ester ◽  
Cost Effective ◽  
Open Circuit ◽  
Active Layer Thickness ◽  
Photovoltaic Properties ◽  
Effective Spin ◽  
Bhj Device

We report on the fabrication and study of bulk heterojunction (BHJ) solar cells based on a novel combination of a donor–acceptor poly(9,9-dioctylfluorenyl-2,7-diyl)-co-(N,N0-diphenyl)-N,N′di(p-butyl-oxy-pheyl)-1,4-diamino-benzene) (PFB) and [6, 6]-phenyl-C61-butyric acid methyl ester (PCBM) blend composed of 1:1 by volume. indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate (PEDOT:PSS)/PFB–PCBM/Ag BHJ solar cells are fabricated by a facile cost-effective spin-coating technique. The thickness of the active film (PFB–PCBM) plays an important role in the efficiency of light absorption, exciton creation, and dissociation into free charges that results in higher power conversion efficiency (PCE). In order to optimize the PCE as a function of active layer thickness, a number of solar cells are fabricated with different thicknesses of PFB–PCBM films at 120, 140, 160, 180, and 200 nm, and their photovoltaic characteristics are investigated. It is observed that the device with a 180 nm thick film demonstrates a maximum PCE of 2.9% with a fill factor (FF) of 53% under standard testing conditions (STC) (25 °C, 1.5 AM global, and 100 mW/cm2). The current–voltage (I-V) properties of the ITO/PEDOT:PSS/PFB–PCBM/Ag BHJ devices are also measured in dark conditions to measure and understand different parameters of the heterojunction. Atomic force microscopy (AFM) and ultraviolet-visible (UV-vis) absorption spectroscopy for the PFB–PCBM film of optimal thickness (180 nm) are carried out to understand the effect of surface morphology on the PCE and bandgap of the blend, respectively. The AFM micrographs show a slightly non-uniform and rough surface with an average surface roughness (Ra) of 29.2 nm. The UV-vis measurements of the PFB–PCBM blend exhibit a reduced optical bandgap of ≈2.34 eV as compared to that of pristine PFB (2.88 eV), which results in an improved absorption of light and excitons generation. The obtained results for the ITO/PEDOT:PSS/PFB–PCBM (180 nm)/Ag BHJ device are compared with the ones previously reported for the P3HT–PCBM blend with the same film thickness. It is observed that the PFB–PCBM-based BHJ device has shown two times higher open circuit voltage (Voc) and, hence, enhanced the efficiency.

Photovoltaic Properties of Semiconductor (ZnSe)/Polymer (PEO - Chitosan Blend) Junction for Solar Cells Applications

2006 ◽  
Vol 517 ◽  
pp. 287-289 ◽  
Author(s):  
S.A. Mohamad ◽  
M.H. Ali ◽  
Z.A. Ibrahim ◽  
A.K. Arof
Keyword(s):  
Polymer Film ◽  
Indium Tin Oxide ◽  
Open Circuit Voltage ◽  
Open Circuit ◽  
Photoelectrochemical Cell ◽  
Photoelectrochemical Cells ◽  
Photovoltaic Properties ◽  
Ito Glass ◽  
Solution Cast ◽  
Cast Technique

The properties of ZnSe/PEO junction photoelectrochemical cells have been studied under dark and illuminated conditions. ZnSe was electrodeposited onto an indium tin oxide (ITO) glass and the polymer film of PEO-chitosan: NH4I (+I2) was placed over it followed by another ITO glass. The polymer film was prepared by the solution cast technique. The open circuit voltage (Voc) of the fabricated cells was between 300 mV to 400 mV. In the dark the device operates as a diode while under illumination it operates as a photoelectrochemical cell.

scholarly journals Signal Amplification in an Optical and Dielectric Biosensor Employing Liquid Crystal-Photopolymer Composite as the Sensing Medium

Biosensors ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 81
Author(s):  
Hassanein Shaban ◽  
Shih-Chun Yen ◽  
Mon-Juan Lee ◽  
Wei Lee
Keyword(s):  
Dielectric Constant ◽  
Liquid Crystal ◽  
Uv Irradiation ◽  
Signal Amplification ◽  
Limit Of Detection ◽  
Optical Signal ◽  
Uv Exposure ◽  
Dielectric Anisotropy ◽  
Optical Texture ◽  
Potential Development

An optical and dielectric biosensor based on a liquid crystal (LC)–photopolymer composite was established in this study for the detection and quantitation of bovine serum albumin (BSA). When the nematic LC E7 was doped with 4-wt.% NOA65, a photo-curable prepolymer, and photopolymerized by UV irradiation at 20 mW/cm2 for 300 s, the limit of detection determined by image analysis of the LC optical texture and dielectric spectroscopic measurements was 3400 and 88 pg/mL for BSA, respectively, which were lower than those detected with E7 alone (10 μg/mL BSA). The photopolymerized NOA65, but not the prepolymer prior to UV exposure, contributed to the enhanced optical signal, and UV irradiation of pristine E7 in the absence of NOA65 had no effect on the optical texture. The effective tilt angle θ, calculated from the real-part dielectric constant ε’, decreased with increasing BSA concentration, providing strong evidence for the correlation of photopolymerized NOA65 to the intensified disruption in the vertically oriented LC molecules to enhance the optical and dielectric signals of BSA. The optical and dielectric anisotropy of LCs and the photo-curable dopant facilitate novel quantitative and signal amplification approaches to potential development of LC-based biosensors.

Constructing PbS quantum dot sensitized ZnO nanorod array photoelectrodes for highly efficient photovoltaic devices

2016 ◽  
Vol 94 (7) ◽  
pp. 687-692
Author(s):  
Masood Mehrabian ◽  
Naser Ghasemian
Keyword(s):  
Quantum Dot ◽  
Short Circuit ◽  
Zno Nanorods ◽  
Growth Period ◽  
Short Circuit Current ◽  
Nanorod Array ◽  
Open Circuit ◽  
Zno Film ◽  
Photovoltaic Properties ◽  
Pbs Quantum Dot

Solar cells with ZnO film/ZnO nanorods (NRs)/PbS quantum dot (QD) photoelectrodes were constructed and various properties were studied. The ZnO NRs were grown for different periods varying from 0 (ZnO film) to 30 min (ZnO NR30) and the effect of growth period on the photovoltaic properties was investigated. The cell with ZnO film/PbS QD as photoelectrode showed the open circuit voltage VOC of 0.59 V, short circuit current density JSC of 10.06 mAcm−2, and the power conversion efficiency of 3.29% under one sun illumination (air mass 1.5 global illumination at 100 mWcm−2). In a device containing of ZnO film/ZnO NR10/PbS QD (as photoelectrode), mentioned photovoltaic parameters increased to 0.61 V, 10.47 mAcm−2 and 3.81%, respectively.

Interfacial Energy Alignment at the ITO/Ultra-Thin Electron Selective Dielectric Layer Interface and Its Effect on the Efficiency of Bulk-Heterojunction Organic Solar Cells

2016 ◽  
Vol 16 (4) ◽  
pp. 3248-3253 ◽  
Author(s):  
Eiji Itoh ◽  
Yoshinori Goto ◽  
Yusuke Saka ◽  
Katsutoshi Fukuda
Keyword(s):  
Contact Resistance ◽  
Active Layer ◽  
Surface Potential ◽  
Organic Solar Cells ◽  
Indium Tin Oxide ◽  
Bulk Heterojunction ◽  
Electronic Charge ◽  
Photovoltaic Properties ◽  
Potential Measurement ◽  
Layer Interface

We have investigated the photovoltaic properties of an inverted bulk heterojunction (BHJ) cell in a device with an indium-tin-oxide (ITO)/electron selective layer (ESL)/P3HT:PCBM active layer/MoOx/Ag multilayered structure. The insertion of only single layer of poly(diallyl-dimethylammonium chloride) (PDDA) cationic polymer film (or poly(ethyleneimine) (PEI) polymeric interfacial dipole layer) and titanium oxide nanosheet (TN) films as an ESL effectively improved cell performance. Abnormal S-shaped curves were observed in the inverted BHJ cells owing to the contact resistance across the ITO/active layer interface and the ITO/PDDA/TN/active layer interface. The series resistance across the ITO/ESL interface in the inverted BHJ cell was successfully reduced using an interfacial layer with a positively charged surface potential with respect to ITO base electrode. The positive dipole in PEI and the electronic charge phenomena at the electrophoretic deposited TN (ED-TN) films on ITO contributed to the reduction of the contact resistance at the electrode interface. The surface potential measurement revealed that the energy alignment by the transfer of electronic charges from the ED-TN to the base electrodes. The insertion of the ESL with a large positive surface potential reduced the potential barrier for the electron injection at ITO/TN interface and it improved the photovoltaic properties of the inverted cell with an ITO/TN/active layer/MoOx/Ag structure.

NIR–Vis–UV Light-Responsive Actuator Films of Polymer-Dispersed Liquid Crystal/Graphene Oxide Nanocomposites

2015 ◽  
Vol 7 (49) ◽  
pp. 27494-27501 ◽  
Author(s):  
Zhangxiang Cheng ◽  
Tianjie Wang ◽  
Xiao Li ◽  
Yihe Zhang ◽  
Haifeng Yu
Keyword(s):  
Graphene Oxide ◽  
Liquid Crystal ◽  
Uv Light ◽  
Polymer Dispersed Liquid Crystal ◽  
Polymer Dispersed

scholarly journals Effect of Doping ofCd1−xZnxS/ZnS Core/Shell Quantum Dots in Negative Dielectric Anisotropy Nematic Liquid Crystal p-Methoxybenzylidene p-Decylaniline

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 605
Author(s):  
Ayushi Rastogi ◽  
Fanindra Pandey ◽  
Rajiv Manohar ◽  
Shri Singh
Keyword(s):  
Quantum Dots ◽  
Liquid Crystal ◽  
Dielectric Permittivity ◽  
Nematic Liquid Crystal ◽  
Phase Shifters ◽  
Ion Trapping ◽  
Dielectric Anisotropy ◽  
Core Shell ◽  
Optical Parameters ◽  
Dielectric Parameters

We report the effect of the doping of Cd1−xZnxS/ZnS core/shell quantum dots (CSQDs) in nematic liquid crystal p-methoxybenzylidenep-decylaniline (MBDA) at 0.05 wt/wt%, 0.1 wt/wt%, 0.15 wt/wt%, 0.2 wt/wt%, 0.25 wt/wt%, and 0.3 wt/wt% concentrations of CSQDs in MBDA. Dielectric parameters with and without bias with respect to frequency have been investigated. The change in electro-optical parameters with temperature has also been demonstrated. The increase in the mean dielectric permittivity was found due to the large dipole moment of CSQDs, which impose stronger interactions with the liquid crystal molecules. The dielectric anisotropy changes sign on doping CSQDs in MBDA liquid crystal. It was concluded that the CSQD doping noticeably increased the dielectric permittivity of nematic MBDA in the presence of an electric field. The doping of CSQDs in nematic MBDA liquid crystal reduced the ion screening effect effectively. This phenomenon is attributed to the competition between the generated ionic impurities during the assembling process and the ion trapping effect of the CSQDs. The rotational viscosity of nematic liquid crystal decreased with increasing concentration of the CSQDs, with a faster response time observed for the 0.05 wt/wt% concentration. The birefringence of the doped system increased with the inclusion of CSQDs in MBDA. These results find application in the field of display devices, phase shifters, LC – gratings, TIR waveguide, industries, and projectors.

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