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Effective host materials are required to improve the performance of phosphorescent organic light-emitting diodes (PhOLEDs). Herein, a series of triazine-dibenzofuran-based n-type host materials, DBT1–DBT4, was prepared by varying the substitution position of dibenzofuran. The photophysical, thermal, and electrochemical properties as well as the device performance of these materials were investigated to establish structure–property relationships. The results demonstrated that the substitution position of dibenzofuran significantly affects the chemical structure, resulting in differences in electrochemical and photophysical properties. All the developed materials were utilized in green top-emitting PhOLEDs as an n-type host material mixed with a p-type host (BPCz), and their electroluminescence (EL) properties were assessed by systematically analysing 18 devices. Among them, the green PhOLEDs using a mixed host of DBT4/BPCz (DBP4-III) displayed the best EL performance with a high current efficiency up to 131.98 cd A−1, an external quantum efficiency up to 30.90%, and a power efficiency up to 105.44 lm W−1 with a device lifetime (T95) of 180 h at 10 000 nits. These findings are expected to aid in the development of improved n-type host materials for highly efficient top-emitting PhOLEDs with long operational lifetimes.

We report on the fabrication of an interactive display system consisting of a stretchable array of electrochromic devices (ECDs) and temperature and strain sensors for visual display of skin temperature and wrist movement. The electrochromic device is prepared by coating poly(3-hexylthiophene) and tungsten trioxide as electrochromic materials on a flexible and transparent electrode of indium-tin-oxide-coated polyethylene terephthalate, and the subsequent assembly of the prepared electrodes using a gel-type electrolyte of Li-mixed 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide/poly(methyl methacrylate). The fabricated ECD exhibits three different colors due to the redox reactions of the electrochromic materials at the corresponding potentials: magenta, violet, and blue at −1.5 V, 0.5 V, and 1.5 V, respectively. By using patterned liquid metal Galinstan interconnections, a stretchable array of the ECDs is fabricated based on a strain relieving mechanism with an island-bridge design, resulting in mechanical stability to repeated stretching of up to 30%. A high-performance strain sensor is fabricated by embedding fragmentized graphene foams inside poly(demithylsiloxane) thin film, and a temperature sensor is prepared by embedding multi-walled carbon nanotubes/polyaniline composite in poly(vinyl alcohol) film. With the integrated system, the strain due to wrist bending and the skin temperature measured by the sensors are displayed as changes in the color pattern of the ECD array aided by an Arduino circuit. This work demonstrates the high potential of our system for application to wearable healthcare devices providing real-time visual display of varied bio-signals.

A highly-durable, highly-flexible transparent electrode (FTE) is developed by applying a composite made of a thin metal grid and a doped conducting polymer onto a colorless polyimide-coated NOA63 substrate. The proposed FTE exhibits a transparency of 90.7% at 550 nm including the substrate and a sheet resistance of 30.3 Ω/sq and can withstand both moderately high-temperature annealing (∼180 °C) and acidic solution (70 °C, pH 0.3) processes without performance degradation. The fabricated FTE yielded good mechanical stability under 10 000 cycles of bending deformations at a bending radius less than 1 mm without degradation of electrical conductivity. The high durability of the proposed FTE allows for the fabrication of flexible energy harvesting devices requiring harsh conditions, such as highly flexible perovskite solar cells (FPSCs) with a steady-state power conversion efficiency (PCE) of 12.7%. Notably, 93% of the original PCE is maintained after 2000 bending cycles at an extremely small bending radius of 1.5 mm. The FPSCs installed on curved surfaces of commercial devices drive them under various environments. The applicability of the proposed FTE is further confirmed via the fabrication of a flexible perovskite light-emitting diode. The proposed FTE demonstrates great potential for applications in the field of flexible optoelectronic devices.

Background and aims Renal dysfunction is a potent risk factor for cardiovascular diseases, including stroke. This study aimed to evaluate the impact of admission estimated glomerular filtration rate (eGFR) levels on short-term (1-month) and long-term (1-year) mortality in patients with acute ischemic stroke. Methods From the Taiwan Stroke Registry data, we classified ischemic stroke patients, identified from April 2006 to December 2015, into 5 groups by eGFR at admission: ≥ 90, 60–89, 30–59, 15–29, and Results Among 52,732 ischemic stroke patients, 1480 died within one month. The 1-month mortality rate was over 5-fold greater in patients with eGFR Conclusions After acute ischemic stroke, patients with reduced eGFR are at elevated risks of short-term and long-term deaths in a graded relationship.

In this report, high sensitivity pressure and temperature sensors are demonstrated based on a single common active material of poly(3-hexylthiophene-2,5-diyl) (P3HT)-coated elastic carbon foam (ECF) for bio-signal monitoring. A conductive microporous elastic foam is obtained via direct carbonization of a commercially available melamine foam at 700 °C and a subsequent dip coating with P3HT. The design incorporating interdigitated electrodes on the bottom of the P3HT-coated ECF is used to fabricate a high-performance pressure sensor with a high pressure sensitivity of 102.4 kPa−1 (

We investigated the impact of serum cholesterol levels on 30-day mortality after ischemic stroke in dialysis patients.From the Taiwan Stroke Registry data, we identified 46,770 ischemic stroke cases, including 1101 dialysis patients and 45,669 nondialysis patients from 2006 to 2013.Overall, the 30-day mortality was 1.46-fold greater in the dialysis group than in the nondialysis group (1.75 versus 1.20 per 1000 person-days). The mortality rates were 1.64, .62, 2.82, and 2.23 per 1000 person-days in dialysis patients with serum total cholesterol levels of 120 mg/dL, 120-159 mg/dL, 160-199 mg/dL, and ≥200 mg/dL, respectively. Compared to dialysis patients with serum total cholesterol levels of 120-159 mg/dL, the corresponding adjusted hazard ratios of mortality were 4.20 (95% confidence interval [CI] = 1.01-17.4), 8.06 (95% CI = 2.02-32.2), and 6.89 (95% CI = 1.59-29.8) for those with cholesterol levels of 120 mg/dL, 160-199 mg/dL, and ≥200 mg/dL, respectively.Dialysis patients with serum total cholesterol levels of ≥160 mg/dL or 120 mg/dL on admission are at an elevated hazard of 30-day mortality after ischemic stroke.

We report on the fabrication of a high performance flexible micro-supercapacitor (MSC) for powering a vertically integrated skin-attachable strain sensor on a gecko-inspired micro-structured adhesive. Combined utilization of the mixed manganese/vanadium (Mn/V) oxide grown on MWCNT electrode and the sulfone-based electrolyte, PC/SL/LiClO4/PMMA, enhances both the capacitance and operation voltage up to 2 V of MSC. Thus, the fabricated MSC exhibits excellent electrochemical performance with an areal capacitance of 11.8 mF cm−2 and an areal energy density of 6.58 µWh cm−2 at an areal power density of 200 µW cm−2. The MSC shows mechanical stability over 1000 repetitive bends at a bending radius of 3.7 mm. The strain sensor made of fragmentized graphene foam embedded in PDMS film provides a high gauge factor of 12.6 up to 50% strain to detect strains due to various bio-signals. Our gecko-inspired adhesive made of PDMS micropillars inked with a mixture of PDMS and Silbione to have spatula tips exhibits not only high adhesion property but also high durability over repeated cycles of attachment-detachment and negligible skin irritation. After vertical integration of the MSC, strain sensor, and the adhesive film, bio-signals such as an arterial pulse, swallowing, and frowning of the brow are successfully detected using energy stored in the MSC.

A series of double donor-acceptor organic dyes (C4 C12) have been synthesized to investigate the influence of the alkyl chain length between the two chromophores on the performance of dye sensitized solar cells (DSSCs). The chain length dependent performance was investigated further using the electrochemical impedance and stepped light induced transient measurement methods. Dye with longer alkyl chain (C6 C12) shows a broader and higher IPCE as well as photo-current density (Jsc) with an enhanced photovoltage (Voc) relative to the reference PTZ-S. In contrast, C4 with shorter alkyl chain presents a relatively low IPCE within the whole spectral region, along with low Jsc and Voc, which predominately arising from the short electron diffusion length with significant electron loss during charge transport. The higher Jsc and Voc obtained with the devices incorporating C10 and C12 dyes with long alkyl chain resulted in a higher conversion efficiencies of 4.02% and 4.03%, respectively, (3.14% for single donor-acceptor dye PTZ-S). Density functional theory simulations were also performed to examine the effect of the alkyl chain length on electrochemical and optical properties of the dyes. Adsorption studies of the dyes on TiO 2 clusters were carried out to explain the variation in Jsc with the alkyl chain length.

The effect of chenodeoxycholic acid (CDCA) used as the coadsorbent with a symmetrical squaraine (SSQ) sensitizer on TiO2-based solar cells was investigated, and it was found that the coadsorbent re...

An organic sensitizer with a multi-anchoring system is a versatile methodology for enhancing the stability and conversion efficiency of dye-sensitized solar cells (DSSCs). Triphenylamine dyes (TPA3T1A ∼ 3A) containing different numbers of anchoring groups are synthesized to determine the correlation between the number of anchoring groups and photovoltaic properties as photosensitizers for DSSCs. The adsorption properties of the dyes on TiO2 electrode were examined by ATR-FT-IR, which show that a mono-anchoring TPA3T1A system adsorbs in monodentate ester-type mode, and the three carboxylic acids in TPA3T3A adsorbs in bidentate bridging mode. The multi-anchoring dye exhibits strong electronic coupling with TiO2, providing an efficient charge injection rate. Moreover, they increased the electron lifetime significantly by suppressing the charge recombination probability. This synergistic effect enables the fabrication of efficient photovoltaic devices. Furthermore, enhanced long-term stability is also observed in the DSSCs containing a tri-anchoring system compared to the mono- and bi-anchoring systems.

CH3NH3PbX3 (MAPbX3) perovskites have attracted considerable attention as absorber materials for solar light harvesting, reaching solar to power conversion efficiencies above 20%. In spite of the rapid evolution of the efficiencies, the understanding of basic properties of these semiconductors is still ongoing. One phenomenon with so far unclear origin is the so-called hysteresis in the current–voltage characteristics of these solar cells. Here we investigate the origin of this phenomenon with a combined experimental and computational approach. Experimentally the activation energy for the hysteretic process is determined and compared with the computational results. First-principles simulations show that the timescale for MA+ rotation excludes a MA-related ferroelectric effect as possible origin for the observed hysteresis. On the other hand, the computationally determined activation energies for halide ion (vacancy) migration are in excellent agreement with the experimentally determined values, suggesting that the migration of this species causes the observed hysteretic behaviour of these solar cells., The origin of hysteresis remains an open question in lead-halide perovskite solar cells. Here, Meloni et al. investigate the causes of hysteresis using an experimental and computational approach, finding that the observed hysteresis is due to halide ion-vacancy movement in the perovskite.

We report on the fabrication of a fractal-designed transparent and stretchable (TS) microsupercapacitor (MSC) as a skin-attachable energy storage device for driving an integrated strain sensor (SS). The MSC is designed to have a fractal structure with long and narrow patterns to ensure high transparency and stretchability. MnO2/Carbon nanotubes (CNTs) and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide/poly(methyl methacrylate) ([BMIM][TFSI]/PMMA) are used as electrodes and a stretchable electrolyte for the MSC, respectively. The fabricated MSC exhibits high transparency of 79% and an areal capacitance of 12.6 mF cm−2 at a current density of 5 mA cm−2. The TS MSC shows excellent mechanical stability in that it can maintain stable electrochemical performance even after 2000 repeated stretching cycles up to 30%. The TS SS is facilely prepared via spray coating of Ag nanowires (NWs) and subsequent curing of PDMS, where the transparency and the electrical resistance are controlled by adjusting the deposited volume of Ag NWs. Wrist bending and a wrist pulse are detected by the SS driven with the stored energy of the MSC. This work demonstrates the possible application of our TS MSC to future skin-attachable electronics as an integrated energy storage device.

Here, we report on a highly conductive, stretchable, and transparent electrode of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) fabricated via modification with triblock copolymer, poly(ethylene glycol)–block–poly(propylene glycol)–block–poly(ethylene glycol) (PEO20–PPO70–PEO20, Pluronic P123), and post-treatment with sulfuric acid. The fabricated electrode exhibits high transparency (89%), high electrical conductivity (∼1700 S/cm), and minimal change in resistance (∼4%) under repetitive stretch–release cycles at 40% tensile strain after stabilization. P123 acts as a secondary dopant and plasticizer, resulting in enhanced electrical conductivity and stretchability of PEDOT:PSS. Furthermore, after sulfuric acid post-treatment, P123 helps the electrode to maintain its stretchability. A successful demonstration of the stretchable interconnection was shown by stretching the P123-modified PEDOT:PSS electrodes, which were connected with light-emitting diodes (LEDs) in series. Finally, a st...

Hybrid organic–inorganic metal perovskites have emerged as highly promising materials for solar energy conversion. However, key questions regarding the working principles of perovskite solar cells remain to be answered in order to improve the design of such devices. In the present study, we have investigated the influence of excess excitation energy on the initial photo-products generated from FTO/meso-TiO2/CH3NH3PbI3 samples. We find that upon resonant excitation at the band edge, part of the formation of free charges passes via an excitonic state that dissociates on the sub-picosecond time scale. An exciton binding energy of

A stretchable polyaniline nanofiber temperature sensor array with an active matrix consisting of single-walled carbon nanotube thin-film transistors is demonstrated. The integrated temperature sensor array gives mechanical stability under biaxial stretching of 30%, and the resultant spatial temperature mapping does not show any mechanical or electrical degradation.

Organometal halide perovskites have emerged as promising next-generation solar cell technologies presenting outstanding efficiencies. However, many questions concerning their working principles remain to be answered. Here, we present a detailed study of hole transfer dynamics into polymeric hole transporting materials (HTMs), poly(triarylamine) (PTAA), poly(3-hexylthiophee-2,5-diyl (P3HT), and poly[2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b']dithiophene)-alt-4,7-(2,1,3-benzothiadiazole) (PCPDTBT). The hole transfer dynamics are shown to occur on a time scale of thousands of picoseconds, being orders of magnitude slower compared to hole transfer involving commonly used Spiro-OMeTAD as HTM.

The effect of the presence of unreacted PbI2 on the perovskite solar cells efficiency is reported. N,N-Dimethylformamide vapor treatment is introduced to study the influence of complete conversion to a power conversion efficiency of the device. It is discovered that the optimized morphology of the PbI2 under layer is essential to form a dense perovskite layer preventing recombination by direct contact between TiO2 and a hole transporting layer, and to increase the charge collection efficiency. The present findings provide an insight into the morphology and growth mechanism of perovskite layer, the correlation between the device performance, and the film deposition process.

A pn-tandem dye-sensitised solar cell (pn-DSSC) employing a set of sensitisers with complementary absorption spectra and a less-corrosive cobalt-based electrolyte is presented. We applied three organic sensitisers (denoted C343, DCBZ, and SQ) featuring different absorption wavelengths for the p-DSSC, while keeping the n-DSSC sensitiser (denoted DCA10CN2) constant. Characterisation of the Co+2/+3-based DSSC devices revealed that SQ dye, with a longer absorption wavelength, showed broader spectra and increased photocurrent activity in the visible and near-infrared region compared to the other two devices with C343 and DCBZ in the pn-DSSCs. As a result, the short-circuit current density increased significantly to 4.00 mA cm−2, and the devices displayed overall power conversion efficiencies of as high as 1.41%, which is comparable to that of the best pn-DSSCs in the literature. Our results demonstrate that complementary absorption between the two photoelectrodes is important for enhancing the photovoltaic performance of pn-DSSCs.

We investigated the effect of Ta doping on the dielectric and piezoelectric properties of lead-free (K0.5Na0.5)NbO3 ceramics prepared using a conventional ceramic processing. X-ray diffraction analysis revealed that Ta was perfectly substituted into Nb-sites in the range of 0 to 20 at%. As Ta content in the KNN increased, the sinterability of KNN ceramics was significantly degraded while the Ta doping enhanced the piezoelectric constant d33, planar mode piezoelectric coupling coefficient (kp), and electromechanical quality factor (Qm). The highest values for d33, kp, and Qm was found to be 156 pC/N, 0.37, and 155, respectively.

A flexible liquid metal loudspeaker (LML) is demonstrated consisting of a gallium-based eutectic liquid metal (Galinstan) and basic aqueous electrolyte (NaOH(aq) ). The LML is driven by liquid metal motion induced by the electrochemically controlled interfacial tension of the Galinstan in NaOH(aq) electrolyte under an applied alternating current (AC) voltage. The fabricated LML produces sound waves in the human audible frequency band with a sound pressure level of ≈40-50 dB at 1 cm from the device and exhibits mechanical stability under bending deformation with a bending radius of 3 mm. Various sounds can be generated with the LML from a single tone to piano notes and human voices. To understand the underlying mechanism of sound generation by the LML, motion analyses, sound measurements, and electrical characterization are conducted at various frequencies. For the first time, this work suggests a new type of liquid metal-based electrochemically driven sound generator in the field of flexible acoustic devices that can be applied to future wearable electronics.

We investigate two different types of TiO2 blocking layer (BL) deposition techniques commonly used in solid-state methylammonium lead triiodide perovskite (MaPbI(3))-based solar cells. Although these BLs lead to similar photovoltaic device performance, their structure and blocking capability is actually very different. In one case, the "blocking" layer is porous, allowing an intimate contact of the perovskite with the fluorine-doped tin-dioxide (FTO)-covered glass substrate serving as transparent electron collector. This interface between the perovskite and the FTO shows rectifying behavior. Reverse biasing of such a solar cell allows the determination of the valence-band position of the MaPbI(3) and the theoretical maximum attainable photovoltage. We show that under reverse bias strong photocurrent amplification is observed, permitting the cell to work as a high-gain photodetector at low voltage. Without BL, the solar-cell performance decreased, but the photocurrent amplification increased. At 1 V reverse bias, the photocurrent amplification is above a factor of 10 for AM 1.5 solar light and over 100 for lower light intensities.

The photovoltaic performance of Sb2 Se3 -sensitized heterojunction solar cells, which were fabricated by a simple deposition of Sb2 Se3 on mesoporous TiO2 by an approach that features multiple cycles of spin coating with a single-source precursor solution and thermal decomposition, is reported. Poly[2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b']dithiophene)-alt-4,7(2,1,3-benzothioadiazole)] was used as the hole-transporting material. The most efficient cell exhibited a short-circuit current density of 22.3 mA cm(-2) , an open-circuit voltage of 304.5 mV, and a fill factor of 47.2 %, yielding a power conversion efficiency of 3.21 % under standard test conditions (irradiation of 1000 W m(-2) , air mass=1.5 G). The results of this study imply that the developed approach has a high potential as a simple and effective route for the fabrication of efficient and inexpensive solar cells.

A vertically aligned TiO2 photoelectrode with sufficient space between TiO2 nanorods was synthesized by sacrificial templating of ZnO nanorods grown on a dense TiO2 layer/FTO film. The more expanded pore space in the TiO2 nanorod film than conventional mesoscopic TiO2 film greatly reduces the mass transport problem of cobalt electrolyte in the vicinity of the Sb2S3 sensitizer in Sb2S3-sensitized photoelectrochemical solar cells. Therefore, the nonlinearity of the power conversion efficiency (PCE) under illumination intensity was greatly relieved to 5.0% (0.1 sun), 4.7% (0.5 sun), and 3.7% (1 sun) in a TiO2-nanorod-based Sb2S3-sensitized solar cell, whereas the efficiency of a mesoscopic-TiO2-based solar cell was significantly degraded to 5.3% (0.1 sun), 3.8% (0.5 sun), and 2.3% (1 sun).

Thin-film photovoltaics play an important role in the quest for clean renewable energy. Recently, methylammonium lead halide perovskites were identified as promising absorbers for solar cells(1). In the three years since, the performance of perovskite-based solar cells has improved rapidly to reach efficiencies as high as 15%(1-10). To date, all high-efficiency perovskite solar cells reported make use of a (mesoscopic) metal oxide, such as Al2O3, TiO2, or ZrO2, which requires a high-temperature sintering process. Here, we show that methylammonium lead iodide perovskite layers, when sandwiched between two thin organic charge-transporting layers, also lead to solar cells with high power-conversion efficiencies (12%). To ensure a high purity, the perovskite layers were prepared by sublimation in a high-vacuum chamber. This simple planar device structure and the room-temperature deposition processes are suitable for many conducting substrates, including plastic and textiles.

Urchinlike nanostructure of well-defined Sb(2)S(3) crystals of 3-4 μm in length and 30-150 nm in diameter oriented along [001] direction have been produced at a mild reaction temperature of 90 °C from SbCl(3) and S-methyl 3-phenyldithiocarbazate [C(6)H(5)NHNHC(S)SMe] in ethylene glycol medium. During the reaction, the amorphous Sb(2)S(3) spheres of 1.4 μm in diameter were formed at early reaction stage and then crystalline nanorods were continuously grown at the surface of Sb(2)S(3) spheres while transforming their morphology into urchinlike structure. The urchinlike Sb(2)S(3) was composed of single-crystalline Sb(2)S(3) nanorods, belong to the orthorhombic phase with cell parameters a = 11.307 Å, b = 11.278 Å, c = 3.847 Å and absorbed the light up to 750 nm-wavelength region. The urchinlike Sb(2)S(3) architecture was applied to the photoelectrochemical cell.

CdSe-sensitized heterojunction solar cells composed of mesoscopic TiO2/CdSe/P3HT (poly-3-hexylthiophene) were constructed, and the negative molecular dipole of 4-methoxybenzenethiol (MBT) and the ZnS passivation layer were used as interface modifiers to improve device performance. Through the interface modification between TiO2/CdSe and P3HT using MBT and by ZnS surface passivation, the power conversion efficiency of the modified solar cell was greatly enhanced from 1.02% to 1.62% under 1 sun illumination.

Iodide redox (3I−/I3−), polysulfide redox (S2−/Sx2−), organic redox [TMTU/TMFDS2+: tetramethylthiourea/tetramethylformaminium-bis(trifluoromethanesulfonyl)imide], ferrocene redox (Fc/Fc+), nickel redox [Ni(II)/Ni(III)], and cobalt redox [Co(II)/Co(III)] hole conducting electrolytes were systematically investigated to determine their suitability for use in Sb2S3-sensitized photoelectrochemical solar cells. A long-term stability test and UV-visible spectral analyses revealed that Sb2S3-sensitized photoelectrochemical solar cells worked stably with Co(II)(o-phen)3(TFSI)2/Co(III)(o-phen)3(TFSI)3 [TFSI: bis(trifluoromethanesulfonyl)imide] as the redox mediator.

Nanoporous metal oxide electrodes provide a high internal area for dye anchoring in dye-sensitized solar cells, but the thickness required to extinguish the solar photons also enhances recombination at the TiO(2)/electrolyte interface. The high extinction coefficient of inorganic semiconductor absorber should allow the reduction of the film thickness, improving the photovoltage. Here we study all-solid semiconductor sensitized solar cells, in the promising TiO(2)/Sb(2)S(3)/P3HT configuration. Flat and nanostructured cells have been prepared and analyzed, developing a cell performance model, based on impedance spectroscopy results, that allows us to determine the impact of the reduction of metal oxide film thickness on the operation of the solar cell. Decreasing the effective surface area toward the limit of flat samples produces a reduction in the recombination rate, increasing the open circuit potential, V(oc), while providing a significant photocurrent. However, charge compensation problems as a consequence of inefficient charge screening in flat cells increase the hole transport resistance, lowering severely the cell fill factor. The use of novel structures balancing recombination and hole transport will enhance solid sensitized cell performance.

The mesoscopic Sb 2 S 3 -sensitized photoelectrochemical solar cells using cobalt redox electrolyteexhibit nonlinear behavior of power conversion efficiency with illuminated sun intensity. From themeasurement of bulk diffusion and electrochemical impedance spectroscopy studies, we suggestthat the nonlinearity of device performance with illuminated sun intensity is attributed not to theslow bulk diffusion problem of cobalt electrolyte but to the limited mass transport in narrowed porevolume in mesoscopic TiO 2 electrode.Keywords : Sb 2 S 3 , Photoelectrochemical solar cell, TiO 2 , Cobalt electrolyte Received September 15, 2011: Accepted September 29, 2011 1. Introduction Since Gratzel et al. 1) reported a mesoscopic dye-sensitized photoelectrochemical solar cell with highpower conversion efficiency over 11% at 1 sun illumination,the sensitized photoelectrochemical solar cells have beenintensively studied due to their distinguished device structurefrom conventional p-n heterojunction solar cells. The sensi-tized solar cells are comprised to mesoscopic photoanode,sensitizer, and redox electrolyte which has correspondingrole of electron conductor, light absorber, and hole con-ductor, respectively. This unique device architecture enablesthe sensitized solar cells to hold cost-effectiveness.Recently inorganic semiconductors have been con-sidered as a promising alternative of conventional dyesbecause of their peculiar properties such as easy chargeseparation by higher dipole moment, ~10 fold higherextinction coefficient than Ru/organic dyes, convenientbandgap tunability by size control, and multiple excitongeneration.

We fabricated CdSe-sensitized photoelectrochemical solar cell by depositing CdSe nanoparticles on nanoporous (np-) via spray pyrolysis deposition method. By adjusting the amount of CdSe-sensitizer deposited on np-, we can fabricate an efficient CdSe-sensitized solar cell ( = 3.0% under 1 sun irradiation) in polysulfide liquid electrolyte.

In inorganic semiconductor (such as CdS)-sensitized solar cells, isolated nanoparticles (including quantum dots) or Porous semiconducting layers are particularly efficient and effective in extracting charge carriers generated by solar energy, without a serious recombination among sensitizers. In this study, porously structured CdS was formed by spray pyrolysis deposition (SPD) using an excess cadmium chloride and thiourea aqueous mixture solution onto an mp-TiO2 substrate pre-heated to 450 °C in an air atmosphere and subsequent washing of the excess cadmium chloride using deionized water. As expected, the power conversion efficiency of a photoelectrochemical solar cell fabricated with the porous CdS was greatly improved, to 1.71%, the highest efficiency ever reported for CdS-sensitized solar cells employing polysulfide as an electrolyte. This improvement in performance is attributed to the efficient transport of the charge carriers generated in CdS.

We were able to attach CdSe quantum dots (QDs) having a ZnS inorganic glue layer directly to a mesoporous TiO(2) (mp-TiO(2)) surface by spray coating and thermal annealing. Quantum-dot-sensitized solar cells based on CdSe QDs having ZnS as the inorganic glue layer could easily transport generated charge carriers because of the intimate bonding between CdSe and mp-TiO(2). The application of spray pyrolysis deposition (SPD) to obtain additional CdSe layers improved the performance characteristics to V(oc) = 0.45 V, J(sc) = 10.7 mA/cm(2), fill factor = 35.8%, and power conversion efficiency = 1.7%. Furthermore, ZnS post-treatment improved the device performance to V(oc) = 0.57 V, J(sc) = 11.2 mA/cm(2), fill factor = 35.4%, and power conversion efficiency = 2.2%.

Porous CdSe layers were prepared by spray pyrolysis deposition using sodium selenosulfate as a selenium source and its surface area and porosity were increased by the dissolution of sodium sulfate formed as by-product. The porous CdSe as both photoanode and absorber could efficiently transport electrons to fluorine-doped tin oxide electrode and extract holes to the electrolyte. The cells were optimized by controlling the number of spray pyrolysis deposition cycles and then etching with sodium sulfate. An efficient solar cell having a power conversion efficiency of 2.6% at 1 sun illumination (100 mW cm −1 ) was fabricated. Further, we extend this approach to fabricate an efficient porous CdS-sensitized solar cell with power conversion efficiency greater than 1.0% at 1 sun illumination.

The p-type Cu 2 S layer is deposited onto p-type mesoporous NiO electrode by spray pyrolysis deposition method using alcoholic solution of ethylenediamine-copper(II) complex and thiourea. A solar cell using Cu 2 S-deposited NiO mesoporous photocathode has been fabricated for the first time. The incident photon to current conversion efficiency (IPCE) values are found to be 0.8–1.8% for the newly designed NiO/Cu 2 S solar cell. It was shown that the p-type NiO/Cu 2 S structure could be successfully utilized to fabricate p-type solar cell and the possible mechanism for charge transfer is also discussed.

The Al2 O3 passivation layer is beneficial for mesoporous TiO2 -based perovskite solar cells when it is deposited selectively on the compact TiO2 surface. Such a passivation layer suppressing surface recombination can be formed by thermal decomposition of the perovskite layer during post-annealing.

The effect of ozone on the formation and the removal of disinfection byproducts(DBPs) of chlorination process was studied to elucidate the performance of water treatment process. The samples of raw water, prechlorination process, and preozonation process were analyzed quantitatively according to the Standard Methods for the Examination of drinking water. As a result, most of total trihalomethanes(THMs) which were formed in prechlorine treatment process was not removed in the preozonation process. Most of haloacetic acids(HAAs), haloacetonitriles(HANs), and chloral hydrate(CH) was removed in sedimentation and biological activated carbon(BAC) filtration processes. However, DBPs were increased more or less by postchlorine step. In particular, the formation of THMs and HAAs depends on ozone more than chlorine, but, the formation of HANs and CH depends on chlorine more than ozone. The seasonal variation of DBPs concentration for the year needs to be investigated to study the temperature effect because DBPs strongly depend on temperature among various efficient factors.

This study describes a modification of the technique for human error analysis in nuclear power plants (NPPs) which adopts advanced Man-Machine Interface (MMI) features based on computerized working environment, such as LCOs. Flat Panels. Large Wall Board, and computerized procedures. Firstly, the state of the art on human error analysis methods and efforts were briefly reviewed. Human error analysis method applied to NPP design has been THERP and ASEP mainly utilizing Swain`s HRA handbook, which has not been facilitated enough to put the varied characteristics of MMI into HRA process. The basic concepts on human errors and the system safety approach were revisited, and adopted the process of FMEA with the new definition of Error Segment (ESJ. A modified human error analysis process was suggested. Then, the suggested method was applied to the failure of manual pump actuation through LCD touch screen in loss of feed water event in order to verify the applicability of the proposed method in practices. The example showed that the method become more facilitated to consider the concerns of the introduction of advanced MMI devices, and to integrate human error analysis process not only into HRA/PRA but also into the MMI and interface design. Finally, the possible extensions and further efforts required to obtain the applicability of the suggested method were discussed.

The protonation equilibrium of 5-substituted 2-furaldehydes is investigated spectrophotometrically in aqueous sulfuric acid at 25 o C and the basicity constants(pK BH+) of the substrates is calculated by means of the excess acidity method. The basicity constant of 5-metyl-2-furaldehyde having electron donating group is larger than that of 5- nitro-2-furaldehyde having electron withdrawing group. Difference between the basicity constants(pK BH+) of these two compounds was about 3.25 pK unit. The m* value which is the degree of solvation of the protonated substrate is similar to that of acetophenone having same protonation site. The dependence of pK BH+ on m* value shows good linear cor- relation.