In this report, a pivotal improvement in the performance of dye‐sensitized solar cells has been achieved, thus taking it one step closer toward the commercialization. Through the stepwise modification on the anthracene‐based organic sensitizers, the alteration of alkyl to alkoxy chain and incorporation of electron deficient moieties in the new sensitizing dyes TY3, TY4, and TY6 are found to play a significant role in the efficiency enhancement. The dye TY6, when tested under 1 sun (AM 1.5G) illumination, is found to exhibit the best efficiency of 8.08% in the series reported here. Taking it further, sensitizer TY6 achieves a milestone by displaying an efficiency of 28.56% when tested under T5 fluorescent illumination of 6000 lux and 20.72% under same illuminance from a commercial light emitting diode light source. Such an excellent performance can be attributed to its outstanding J SC and V OC, which are characteristic properties of these anthracene dyes.

We have devised new porphyrin dye Y1A1 for photovoltaic application under both light sources of AM1.5G standard condition and low light intensity at 300 ~ 2400 lux. The dye Y1A1 tailored with two 3,5-di-tert-butyl-4-methoxyphenyl groups at meso-10,20-positions which helps the solubility of the molecule in solvents and avoids involvement of the hazardous chemical n-butyllithium during the synthesis of some typical high efficiency porphyrins such as YD2-o-C8 and LD-series dyes. The dye is also structurally simple so that large-scale synthesis for future industrial application becomes feasible. The Y1A1-based cells were found to exhibit higher performance using I -/I 3 rather than Co 2+/3+ electrolyte in the presence of CDCA co-adsorbent. Addition of Li + together with removal of GuSCN as electrolyte additives benefit the performance in terms of higher capacitance at compensate of surface charge recombination and electron lifetime. The optimized cells based on Y1A1 showed a power conversion efficiency of 9.22% at AM1.5G condition and as high as 19.5%illuminated under 350 lux of LED light. IntroductionSolar cells are well-known technologies in terms of converting energy from sun to a flow of electrons. To provide a controllable and comparable testing condition for solar cells, standard 1 Sun condition (100 mW cm -2 ) is generally equipped in the laboratory for mimicking the outdoor environments which typically shed lights with intensity of >100,000 lux. In contrast, indoor lights surrounding the living places of the community can be considered as low light or dim light due to relatively lower photon flux. These places including homes, schools, offices, factories, hospitals and stores require brightness of light sources typically ranging between 300~500 lux. Higher light level demand for specific area such as laboratories, reading rooms, production halls, first aids and show rooms require the illuminated light of 500~1500 lux. With the thriving concept of indoor energy-harvesting aiming at these reachable light sources, dye-sensitized solar cells (DSCs) are certainly one of the most promising light-to-electricity conversion technologies. 1 DSCs have drawn growing attention since the pioneer work initiated by Grätzel's groups. 2 In the past two decades, molecular engineering of dyes yields several kinds of molecular architectures for efficient solar-to-electricity conversion. 3, 4 These high performance dyes includes the ruthenium polypyridyl complexes, 5, 6 the arylamine-based organic dyes 7-12 and the porphyrin-based dyes. 13-15 Graphical AbstractA new porphyrin dye Y1A1 has been devised for high performance dye-sensitized solar cells under the irradiance of either AM1.5G simulated sunlight or fluorescent/LED based dim light.

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The need for low-cost and highly efficient dyes for dye-sensitized solar cells under both the sunlight and dim light environments is growing. We have devised GJ-series push-pull organic dyes which require only four synthesis steps. These dyes feature a linear molecular structure of donor-perylene-ethynylene-arylcarboxylic acid, where donor represents N,N-diarylamino group and arylcarboxylic groups represent benzoic, thienocarboxylic, 2-cyano-3-phenylacrylic, 2-cyano-3-thienoacrylic, and 4-benzo[c][1,2,5]thiadiazol-4-yl-benzoic groups. In this study, we demonstrated that a dye without tedious and time-consuming synthesis efforts can perform efficiently. Under the illumination of AM1.5G simulated sunlight, the benzothiadiazole-benzoic-containing GJ-BP dye shows the best power conversion efficiency (PCE) of 6.16% with V of 0.70 V and J of 11.88 mA cm using liquid iodide-based electrolyte. It also shows high performance in converting light of 6000 lx light intensity, that is, incident power of ca. 1.75 mW cm, to power output of 0.28 mW cm which equals a PCE of 15.79%. Interestingly, the benzoic-containing dye GJ-P with a simple molecular structure has comparable performance in generating power output of 0.26 mW cm (PCE of 15.01%) under the same condition and is potentially viable toward future application.

The well-defined Lutetium (III) hexacyanoferrate microparticles were electrodeposited on poly(taurine) modified glassy carbon electrode (GCE), namely (LuHCF/poly(taurine)-GCE). The as-fabricated LuHCF/poly(taurine)-GCE possesses excellent electrochemical activities and high sensitivity toward the sensing of sulfite. The electrochemical oxidation of sulfite on LuHCF/poly(taurine)-GCE is studied by using Cyclic Voltammetry (CV), and Differential Pulse Voltammetry techniques (DPV). Remarkably, the reported modified electrode exhibits high sensitivity (448 μA mM −1 cm −2 ) and limit of detection (1.33 μM) toward the electrochemical oxidation of sulfite with superior selectivity and practicability.

In this work, we have synthesized a novel porphyrin dye named SK7, which contains two N,N-diarylamino moieties at two β-positions as electron-donating units and one carboxy phenylethynyl moiety at the meso-position as an electron-withdrawing, anchoring group. This novel dye was tested for the application in dye-sensitized solar cells. The light-harvesting behavior of SK7 and YD2 was investigated using UV–vis absorption and density functional calculation. The electron transport properties at the TiO2/dye/electrolyte interface for SK7- and YD2-based devices were evaluated by electrochemical impedance spectroscopy. X-ray crystallographic characterization was conducted to understand the influence of two N,N-diarylamino units at two β-positions. The power conversion efficiencies of ca. 6.54% under 1 sun illumination (AM 1.5G) and ca. 19.72% under a T5 light source were noted for the SK7 dye. The performance of SK7 is comparable to that of dye YD2, which contains only one N,N-diarylamino moiety at the meso-position (ca. 7.78 and 20.00% under 1 sun and T5 light, respectively).

We present a facile and scalable method to prepare water‐dispersed polyvinylpyrrolidone‐capped graphene (PVP‐graphene) nanoplatelets from an ordinary graphite powder. The 3 D hydrophobic graphite powder was exfoliated into 2 D hydrophilic PVP‐graphene nanoplatelets by inducing intercalation through the PVP chains and through high‐powered sonication. The nanoplatelets were characterized by using XRD, field‐emission scanning electron microscopy, TEM, Raman spectroscopy, and X‐ray photoelectron spectroscopy, and they were found to be nonoxidative and to have dimensions of a few hundred nanometers. The suitability of PVP‐graphene as a catalyst for a CoII/III redox couple was evaluated by coating the prepared PVP‐graphene nanoplatelets on fluorine‐doped tin oxide glass through a unique two‐step dipping method. The coated nanoplatelets were examined by using electrochemical impedance spectroscopy, UV/Vis spectroscopy, and current–voltage curve analysis, and it was observed that PVP‐graphene exhibited a high catalytic effect because the charge transfer resistance from CoIII to CoII was as low as 1.17 Ω cm2. A porphyrin‐sensitized solar cell with this counter electrode and an efficiency of 8.95 % was demonstrated.

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