Solid-state Dye Research Articles

Input/output energy in solid state dye random lasers.

A new approach to the problem of energy in solid state dye random lasers is presented. The measurements performed in terms of absolute energy show that the slope efficiency depends on the measurement conditions. In particular, in lasers with pumping in the picoseconds range, the result is really different if measured by recording the emission in the same time range or in a longer one (nanoseconds range). In the last case, no energy threshold is observed. A previously developed model has been applied to the solid state dye random laser. It is a rate-equations model, based on a distribution of paths with different lengths, which partially share population inversion. The results of the model are satisfactory and show that the dynamic behavior is pretty similar in solid state dye random lasers and in inorganic powders.

Polyaniline nanotube/reduced graphene oxide aerogel as efficient counter electrode for quasi solid state dye sensitized solar cell

Polyaniline nanotube/reduced graphene oxide aerogel (PAniNT/rGOA) is studied as a potential counter electrode material for a quasi-solid-state dye-sensitized solar cell (DSSC) fabricated with poly(methyl methacrylate) based polymer gel electrolyte. The aerogel, prepared via an organic sol–gel route, having a high surface area of 294.73 m2 g−1 exhibits excellent electro-catalytic activity towards the reduction of triiodide ions in the electrolyte. The excellent catalytic activity of the aerogel based electrodes is manifested with cyclic voltammetry based analyses. Electrochemical impedance analyses and current density vs voltage plots are employed to gauze the photovoltaic performance of the DSSCs fabricated with PAniNT/rGOA counter electrode. The thickness of the counter electrode is a crucial factor that affects the performance of the DSSC: thicker films offer more surface area for electro-catalytic reduction reaction whilst increasing the charge and mass transport resistances simultaneously. At an optimum PAniNT/rGOA electrode film thickness of 8.68 µm, a power conversion efficiency of 5.47% is achieved. In addition, an improvement of open circuit voltage is observed due to the capacitance involved at the electrolyte/electrode interface.

Flexible Printed Monolithic-Structured Solid-State Dye Sensitized Solar Cells on Woven Glass Fibre Textile for Wearable Energy Harvesting Applications

Previously, textile dye sensitised solar cells (DSSCs) woven using photovoltaic (PV) yarns have been demonstrated but there are challenges in their implementation arising from the mechanical forces in the weaving process, evaporation of the liquid electrolyte and partially shaded cells area, which all reduce the performance of the cell. To overcome these problems, this paper proposes a novel fabrication process for a monolithic-structured solid-state dye sensitized solar cell (ssDSSC) on textile using all solution based processes. A glass fibre textile substrate was used as the target substrate for the printed ssDSSC that contain multiple layers of electrodes and active materials. The printed ssDSSC on textile have been successfully demonstrated and compared with a reference device made with the same processes on a glass substrate. All PV textile devices were characterized under simulated AM 1.5 conditions and a peak efficiency of 0.4% was achieved. This approach is potentially suitable for the low cost integration of PV devices onto high temperature textiles, but to widen the range of applications future research is required to reduce the processing temperature to enable the device to be fabricated on the standard fabric substrates.

A High-Power and Highly Efficient Semi-Conductor MOPA System for Lithium Atomic Physics

A compact and highly efficient 670.8-nm semi-conductor master oscillator power amplifier (MOPA) system, with a unique optical design, is demonstrated. The MOPA system achieves a continuous-wave (CW) output power of 2.2 W, which is much higher than commercial products using semi-conductor devices. By comparing solid state lasers and dye lasers, higher wall-plug efficiency (WPE) of 20 % is achieved. Our developed laser system also achieves spectral line-width of 0.3 pm (200 MHz) and mode-hop free tuning range of 49 pm (32.6 GHz), which is very suitable for experiments of lithium atomic physics at several-watt power levels, such as Bose-Einstein condensation (BEC) and isotope absorption spectroscopy.

Solid-state emissive O-BODIPY dyes with bimodal emissions across red and near infrared region.

Fluorescent compounds with solid-state emission are expected to have broad applications in the development of optoelectronic devices. In this study, we develop O-BODIPY based fluorescent dyes which exhibit strong bimodal solid-state emissions across red and NIR regions. After one pot synthesis, samples are characterized by X-ray diffraction, cyclic voltammetry, UV-vis absorption, and fluorescence spectra. All the experimental data reveal the multiple excitation and efficient emission features in the aggregation states. Furthermore, the two produced probes can be successfully applied for tracking lysosomes in HeLa cells with low cytotoxicity.

Sequential halochromic/mechanochromic luminescence of pyridyl-substituted solid-state emissive dyes: thermally controlled stepwise recovery of the original emission color

A stepwise temperature-controlled emission-color switch has been achieved in a system that combines halochromic and mechanochromic luminescence in series.

Counter Anion Effect on the Photophysical Properties of Emissive Indolizine-Cyanine Dyes in Solution and Solid State.

Near-infrared emissive materials with tunable Stokes shifts and solid-state emissions are needed for several active research areas and applications. To aid in addressing this need, a series of indolizine-cyanine compounds varying only the anions based on size, dipole, and hydrophilicity were prepared. The effect of the non-covalently bound anions on the absorption and emission properties of identical π-system indolizine-cyanine compounds were measured in solution and as thin films. Interestingly, the anion choice has a significant influence on the Stokes shift and molar absorptivities of the dyes in solution. In the solid-state, the anion choice was found to have an effect on the formation of aggregate states with higher energy absorptions than the parent monomer compound. The dyes were found to be emissive in the NIR region, with emissions peaking at near 900 nm for specific solvent and anion selections.

Synthesis of Indolo[3,2- b]carbazole-Based Boron Complexes with Tunable Photophysical and Electrochemical Properties.

New synthetic strategies were developed for the synthesis of indolo-pyridine boron difluoride (IPBD) dyes and antiladder-type π-conjugated dyes based on the pyridine/pyrazine-indolocarbazole (ICZ) structures. The photophysical and electrochemical properties of the dyes were measured in solution, solid state, and thin films and rationalized by theoretical calculations. Interestingly, these properties of the dyes can be tuned in a wide range using the developed chemical route. For example, the absorption range and fluorescence color of the dyes in solution and solid state and the HOMO-LUMO energy gaps were tuned by structure modulations. The absorption properties of those new boron complexes cover most of the UV-visible-NIR spectrum. Therefore, this appealing tunability feature makes these new types of dyes very promising candidates for their further use in functional material development.

Molecular engineering of triphenylamine functionalized phenoxazine sensitizers for highly efficient solid-state dye sensitized solar cells

Two novel organic dyes POZ7 and POZ8, with D35 donor functionalized phenoxazine (POZ) derivative as donor and cyanoacrylic acid as acceptor, have been developed and applied in the solid-state dye-sensitized solar cells (s-DSCs). Compared with the dye POZ7 without π-bridge (6.24%), an impressive overall conversion efficiency of 7.37% for s-DSCs device based on POZ8 containing one thiophene unit as π-bridge, was obtained under standard AM 1.5 illumination (100 mW cm−2) by using 2, 2‘, 7, 7‘-tetrakis-(N, N-di-pmethoxyphenyl-amine)9, 9‘-spiro-bifluorene (Spiro-OMeTAD) as hole-transport materials (HTMs). This can be attributed to the impressive panchromatic photocurrent response over the whole visible range (380 nm–720 nm), which is much broader than that of POZ7, resulting in a much higher Jsc for POZ8 based device. The results clearly show that POZ derivative could be a promising donor unit to construct efficient dyes for s-DSCs.

Two-Photon Absorption and Fluorescence in Micrometer-Sized Single Crystals of a Rhodamine B Coordinated Metal–Organic Framework

A Rhodamine B (RhB) dye coordinated, 2D metal–organic framework (MOF), {[Zn2(L)(RhB)]·5DMF}n (1; DMF = N,N-dimethylformamide), was constructed solvothermally from a −NH2-functionalized ligand and ZnII ions. The MOF features interlayer π···π interaction between the RhB molecules with an overlap of almost 100%. One- and two-photon-excited fluorescence measurements were carried out on micrometer-sized single crystals of varied thickness with continuous-wave and femtosecond pulsed lasers, respectively. The two-photon absorption coefficient was measured relative to the CdS crystal and found to be 7.1 ± 0.7 cm/GW at a wavelength of 1030 nm. Our findings demonstrate a new way of achieving solid-state dye microlasers or microsized light-frequency upconverters.

Production of Ligninolytic Enzymes from Penicillium Sp. and Its Efficiency to Decolourise Textile Dyes

Background:The present study discussed the bio decolourization of synthetic textile dyes using extracellular crude laccase from an Ascomycetes fungusPenicilliumsp. Laccase based decolourization is found to be potentially advantageous to bioremediation technologies.Methods:In this study, the production of laccase was observed for 7 days of incubation under shaking conditions. Maximum laccase production was secreted by fungal strain on the 6thday of incubation under submerged fermentation. Incubation of fungal mycelium and culture filtrate as crude enzyme obtained fromPenicilliumsp. with textile dyes - Indigo, Reactive black-5, Acid blue -1 and Vat brown -5 on solid PDA medium and liquid PDA broth showed effective biological dye decolourisation.Result:Solid state dye decolourisation had shown 45%, 25%, 50% and 72% colour removal of dyes - Indigo, Reactive black-5, Acid blue -1 and Vat brown -5 whereas maximum decolourization of same dyes of 45%, 20%, 48%, and 75% was obtained in liquid state with crude enzyme within 3h.Conclusion:The results had shown the potential dye decolourisation capacity of thePenicilliumsp. extracellular crude laccase and pave a way to apply this strain on an industrial scale.

Improving the power conversion efficiency of solid state dye sensitized solar cells with a N-oxoammonium salt: 2,2,6,6-Tetramethyl-1-oxopiperidinebromide

P-type doping is a rational strategy for the enhancement of hole transporting properties of the organic semiconductors as well as the device performance of organic photo-electric devices. We originally introduce a stable and solution processed p-type dopant based on N-oxoammonium salts termed 2,2,6,6-tetramethyl-1-oxopiperidinebromide salt (TEMPO-Br) for 2,2′,7,7′-tetrakis(N, N-di-p-methoxyphenyl-amine)9,9′-spirobifluorene (Spiro-OMeTAD) based solid state dye sensitized solar cells (ssDSC). By introducing TEMPO-Br doped Spiro-OMeTAD and a commercialized D-π-A sensitizer into ssDSCs, a promising device performance of 6.83% is achieved under simulated AM 1.5G solar irradiation (100 mW cm−2), which is significantly better than the control devices (∼1.7 times). The doping effect of TEMPO-Br on the photophysical and electrochemical properties of Spiro-OMeTAD, solid state device performance, cationic dye regeneration kinetics and preliminary long-term stability have been systematically investigated. This work indicates a potential application of N-oxoammonium salts as chemical P-type dopants for triphenylamine based hole transporting materials in solid state photo-electric devices.

Interface engineering of cross-linkable ruthenium complex dye to chelate cations for enhancing the performance of solid-state dye sensitized solar cell

In this study a cross-linkable ruthenium complex dye, Ru(2,2′-bipyridine-4,4′-bicarboxylic acid)(4,4′-bis((4-vinyl-benzyloxy)methyl)-2,2′-bipyridine)(NCS)2 denoted as RuS, was applied to the solid-state dye-sensitized solar cell, by which the photovoltaic performance was superior to the traditional N3 dye. However, the power conversion efficiency (PCE) was only 1.48%, resulting from poor pole filling of the hole conductor, 2,2′,7,7′-tetrakis-(N,N-di-4-methoxyphenylamino)-9,9′-spirobifluorene (spiro-OMeTAD). To modify the interface between RuS and spiro-OMeTAD, additional 4,4′-bis((4-vinylbenzyloxy)methyl)-2,2′- bipyridine (BVP) ligand was employed to crosslink with RuS. The cross-linked dye (denoted as RuS-BVP) on TiO2 was more sustainable and the PCE rose to 2.12%. Besides, the outward bipyridine groups of RuS-BVP are capable of chelating cations. As lithium bis(trifluoromethane)sulfonimide was applied to modify the interface between RuS-BVP and spiro-OMeTAD, the PCE increased to 2.55% and the interfacial resistance for charge transfer under sunlight dramatically decreased. As divalent cation compounds such as magnesium, calcium and barium acetylacetonate were individually adsorbed onto the RuS-BVP, the cell with magnesium acetylacetonate has the highest PCE of 2.82%, highest open circuit voltage and lowest interfacial resistance. The results suggest that the cations with higher charge density have stronger Coulomb's force to couple between RuS-BVP and spiro-OMeTAD.

Efficient solid state dye sensitized solar cell based on tricationic ionic crystal pyridinuim-imidazolium electrolytes

We have developed a new series of pyridinium-imidazolium based tricationic ionic crystals with high conductivity, diffusion coefficient and thermal stability. These ionic crystal based electrolytes in ss-DSSCs and the influence of anions (I−, Br− and SCN−) versus the device performances are studied by steady-state voltammography, I-V characteristics and impedance spectroscopy. The PySCN based solid state electrolyte has achieved an optimized efficiency of 7.7% under 100 mWcm−2 and the device based on this solid electrolyte (PySCN) shows an excellent long-term stability, maintaining 95% of the initial efficiency after 600 h.

Solid state dye sensitized solar cells with polyaniline-thiourea based polymer electrolyte composition

The quest for cost effective and efficient solid-state electrolytes is a primary goal for dye sensitized solar cells (DSSCs). The present study describes an experimental approach of synthesizing simple composite electrolytes from iodide-triiodide ions (I−/I3−) incorporated into a polyaniline/thiourea matrix for solid-state DSSC applications. This electrolyte composition can be effectively used to decrease the probability of recombination at the TiO2/electrolyte interface and increase the catalytic process of I3− reduction at the electrolyte/counter electrode interface. The application of the optimized electrolyte in DSSC results in increased open-circuit voltage as well as short circuit current density, thereby increasing the overall efficiency by 73% as compared to the reference electrolyte. The present composition can prove to be a promising redox medium for solid state DSSCs.

Anomalous Effect of Intramolecular Charge Transfer on the Light Emitting Properties of BODIPY.

A new way to approaching highly emissive BODIPY dyes in both solution and solid state is achieved by introducing intramolecular charge transfer (ICT). A hybrid excited state that shows behaviors of both the ICT excited state and local excited state is discovered to be beneficial in avoiding the disturbance from the rotation vibration of the flexible phenyl substituents. Thus, the nonradiative transition process is suppressed, and the fluorescence efficiency goes up. By modification of the excited state, we realize emission enhancement of crystalline BODIPY derivatives with a PLQY from 0.08 to 0.27, and the compound expresses a good potential application prospect in organic semiconductors.

New covalently bonded dye/hole transporting material for better charge transfer in solid-state dye-sensitized solar cells

A novel metal-free organic dye based on triarylamine functionalized by a carbazole unit is synthesized and used in solid state dye sensitized solar cells (sDSC). The carbazole is co-polymerized with bis-EDOT by in-situ photo-electrochemical polymerization leading to a hole transporting polymer material covalently bonded to the light active centre. These first photovoltaic performances results are promising in sDSCs applications.

Two-Directional Tuning of Distributed Feedback Film Dye Laser Devices.

We demonstrate a two-directional tuning method of distributed feedback (DFB) film dye laser devices to achieve high quality lasing and a large tuning range. In this work, we proposed a simple method to fabricate a continuous tunable solid-state dye laser on a flexible Polydimethylsiloxane (PDMS) film. In order to obtain stable and tunable output lasing, the stretching property of the gelatine host was improved by mixing with a certain ratio of glycerol to prevent DFB cavity destruction. We employed two different tuning strategies of the DFB film dye lasers, by stretching the PDMS film in two perpendicular directions, and a nearly 40 nm tuning range in each direction was achieved. The laser device maintained single mode lasing with 0.12 nm linewidth during the tuning process. The reported tunable DFB film dye laser devices have huge potential as coherent light sources for sensing and spectroscopy applications.

Ultra-photo-stable coherent random laser based on liquid waveguide gain channels doped with boehmite nanosheets

Construction of ultra-photo-stable coherent random laser based on liquid waveguide gain channels doped with boehmite nanosheets has been demonstrated. An Al plate uniformly coated with boehmite nanosheets was prepared by an alkali-treatment method and used as a scattering surface for the coherent random laser. Microcavity may be formed between these boehmite nanosheets owing to the strong optical feedback induced by the multiple light scattering. Many sharp peaks are observed in the emission spectra, and their laser thresholds are different, which confirms the feedback mechanism is coherent. The linewidth of the main peak at 571.74 nm is 0.28 nm, and the threshold of the main peak is about 4.96 mJ/cm2. Due to the fluidity of liquid waveguide gain medium, the photostability of this coherent random laser is better than the conventional solid state dye random lasers. The emission direction is well constrained by the waveguide effect within a certain angular range (±30°). This kind of coherent random laser can be applied in optical fluid lasers and photonic devices.

Retraction notice to “Efficient solid state dye sensitized solar cell based on tricationic ionic crystal pyridinuim-imidazolium electrolytes” Org. Electron. 51 (2017) 477-484

Retraction notice to “Efficient solid state dye sensitized solar cell based on tricationic ionic crystal pyridinuim-imidazolium electrolytes” Org. Electron. 51 (2017) 477-484