Fluorine chemistry has gained tremendous attention in the area of electrochemical energy devices such as lithium ion batteries, fuel cells and solar cells. With the advent of novel fluorinating systems, it is interesting to study the effect of fluorine on the electrochemical characteristics of such energy devices. In this study, an organo‐fluorine compound, SelectfluorTM (F‐TEDA) is used as a co‐electrolyte with organic electrolyte, tetrabutyl ammonium tetrafluoroborate (TBABF4) to facilitate the formation of electrostatic double layer. F‐TEDA is a commercially available N−F fluorinating agent existing as ion‐pair resembling conventional electrolytes. The ionic conductivity of 0.5 M F‐TEDA/TBABF4 is found to be 5.10 mS/cm that increases on introduction of ppm level of water indicating its sensitivity towards water. Symmetric Swagelok‐type cells in two electrode geometry are fabricated using carbon cloth as electrodes and F‐TEDA/TBABF4 as electrolyte. F‐TEDA/TBABF4 in inert condition (Device C) exhibits superior supercapacitive behaviour in terms of high rate capability and capacitance retention. The devices are assembled in ambient and inert conditions to examine the influence of moisture on supercapacitor performance. Interestingly, device based on F‐TEDA assembled in ambient condition despite of decrease in voltage window exhibits a remarkable increase in specific capacitance by 102 % with respect to control electrolyte.

Transparent electronics continues to revolutionize the way we perceive futuristic devices to be. In this work, we propose a technologically advanced volatile organic compound (VOC) sensor in the form of a thin-film transparent display fabricated using fluorinated SnO 2 films. A solution-processed method for surface fluorination of SnO 2 films using Selectfluor as a fluorinating agent has been developed. The doped fluorine was optimized to be <1%, resulting in a significant increase in conductivity and reduction in persistent photoconductivity accompanied by a faster decay of the photogenerated charge carriers. A combination of these modified properties, together with the intrinsic sensing ability of SnO 2 , was exploited in designing a transparent display sensor for ppm-level detection of VOCs at an operating temperature of merely 150 °C. Even a transparent metal mesh heater is integrated with the sensor for ease of operation, portability, and less power usage. A sensor reset method is developed while shortening the UV exposure time, enabling complete sensor recovery at low operating temperatures. The sensor is tested toward a variety of polar and nonpolar VOCs (amines, alcohols, carbonyls, alkanes, halo-alkanes, and esters), and it exhibits an easily differentiable response with sensitivity in line with the electrondonating tendency of the functional group present. This work opens up the door for multiplexed sensor arrays with the ability to detect and analyze multiple VOCs with specificity.

Fabrication protocols of transparent conducting electrodes (TCEs), including those which produce TCEs of high values of figure of merit, often fail to address issues of scalability, stability, and cost. When it comes to working with high-temperature stable electrodes, one is left with only one and that too, an expensive choice, namely, fluorine-doped SnO2 (FTO). It is rather difficult to replace FTO with a low-cost TCE due to stability issues. In the present work, we have shown that an Al nanomesh fabricated employing the crack template method exhibits extreme thermal stability in air even at 500 °C, compared with that of FTO. In order to fill in the non-conducting island regions present in between the mesh wires, a moderately conducting material SnO2 layer was found adequate. The innovative step employed in the present work relates to the SnO2 deposition without damaging the underneath Al, which is a challenge in itself, as the commonly used precursor, SnCl2 solution, is quite corrosive toward Al. Optimization of spray coating of the precursor while the Al mesh on a glass substrate held at an appropriate temperature was the key to form a stable hybrid electrode. The resulting Al/SnO2 electrode exhibited an excellent transparency of ∼83% at 550 nm and a low sheet resistance of 5.5 Ω/□. SnO2 coating additionally made the TCE scratch-proof and mechanically stable, as the adhesion tape test showed only 8% change in sheet resistance after 1000 cycles. Further, to give FTO-like surface finish, the SnO2 surface was fluorinated by treating with a Selectfluor solution. As a result, the Al/F–SnO2 hybrid film exhibited one order higher surface conductivity with negligible sensitivity toward humidity and volatile organics, while becoming robust toward neutral electrochemical environments. Finally, a custom-designed projection lithography technique was used to pixelate the Al/SnO2 hybrid film for optoelectronic device applications.

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Recently, there has been substantial interest in the fluorination of nanomaterial thin films used in various optoelectronic devices for optimum charge transport across semiconducting layers. The discovery of electrophilic fluorinating...