Tungsten oxide (WO ) is an emerging 2D nanomaterial possessing unique physicochemical properties extending a wide spectrum of novel applications which are limited due to lack of efficient synthesis of high-quality WO . Here, a facile new synthetic method of forming WO from tungsten sulfide, WS is reported. Spectroscopic, microscopic, and X-ray studies indicate formation of flower like aggregated nanosized WO plates of highly crystalline cubic phase via intermediate orthorhombic tungstite, WO H O phase. The charge storage ability of WO is extremely high (508 F g at current density of 1 A g ) at negative potential range compared to tungstite (194 F g at 1 A g ). Moreover, high (97%) capacity retention after 1000 cycles and capacitive charge storage nature of WO electrode suggest its supremacy as a negative electrode of supercapacitors. The asymmetric supercapacitor, based on the WO as a negative electrode and mildly reduced graphene oxide as a positive electrode, manifests high energy density of 218.3 mWhm at power density 1750 mWm , and exceptionally high power density, 17 500 mW m , with energy density of 121.5 mWh m . Furthermore, the negative differential resistance (NDR) property of both WO and WO .H O are reported for the first time and NDR is explained with density of state approach.

Controlled grafting of polyaniline from the surface of carbon nano dots using ‘grafting from’ strategy is reported. The nano structured polyaniline coated carbon nano dots produced show excellent electrochemical performance.

In aqueous dispersions of graphene quantum dots (GQDs), aniline is in situ polymerized to produce polyaniline-GQDs hybrids and dye-sensitized solar cells fabricated with the hybrids indicate highest power conversion efficiency of 3.12%.

The designed electrochemically modified graphite paper (ECM-GP) having a foam-like structure serves as an advanced electrode substrate of supercapacitors.

We have tuned reduction of graphene oxide (GO) using KI in water (KG) and in acidic medium of different strengths for better supercapacitor and photocurrent performance. FTIR, Raman, WAXS and XPS results indicate that KI in water acts as mild reducing agent, better than thermal reduction but weaker from that in acidic medium. KG exhibits dc-conductivity 0.18 mS/cm and specific capacitance 414 F g À1 at current density 0.5 A g À1 . It exhibits long cyclic stability (~95% after 10,000 cycles), excellent rate capability (56.5% retention at a current density 20 A g À1 ) and high energy density 10.76 W h kg À1 at power density 125 W kg À1 . The supercapacitor performance of KG is attributed to both electrical double layer and pseudocapacitances. On irradiation with light KG exhibits highest photocurrent with a 72 % increase from its dark current showing good cyclic stability. The results are explained from band gap values. Absence of photocurrent at highly reduced GO suggests that oxygenated groups at an optimum concentration is necessary for good photoresponse property. So reduction of GO using KI in water is suitable both for better supercapacitor and photocurrent performances.