▎ 摘　　要

NOVELTY - A graphene oxide complex (I), is new. The graphene oxide complex (I) is a mixture of cubic and hexagonal phased reduced graphene oxide, rGO and cadmium sulfide with nanogates, where G is graphene layer and r is reduction of edge side groups from GO layers. USE - Graphene oxide complex for piezoelectric device (claimed). ADVANTAGE - The graphene oxide complex shows 2.5 time more output voltage, and can be prepared by cost-effective method. DETAILED DESCRIPTION - A graphene oxide complex of formula (I), is new. The graphene oxide complex (I) is a mixture of cubic and hexagonal phased reduced graphene oxide, rGO and cadmium sulfide with nanogates, where G is graphene layer and r is reduction of edge side groups from GO layers. INDEPENDENT CLAIMS are included for the following: (i) preparation of graphene oxide complex (I), which involves (a) converting graphite into graphite oxide, (b) ultrasonically processing a mixture of graphite oxide powder of step (a) in distilled water for a period of 2-3 hours and 1-2 hours probe sonication a temperature of 25-30° C, (c) keeping a dispersed GO obtained at step (b) for stirring at a temperature of 70-80° C for a period of 1-2 hours and purging the resultant mixture with argon for a period of 1-2 hours to afford reduced GO solution, (d) stirring a mixture of cadmium acetate dihydrate in deionized water for a period of 10-15 minutes at a temperature of 50-60° C followed by adding poly (ethylene glycol) (PEG) and stirring for 10-15 minutes and purging the resultant mixture with argon for 1-2 hours, (e) pouring the cadmium-acetate and PEG containing reaction mixture of step (d) into the reduced GO solution of step (c) followed by stirring for a period of 1-2 hours at a temperature of 70-80° C with argon purging, (f) stirring a solution of sodium sulfide in deionized water for a period of 1-2 hours at a temperature of 50-60° C with argon purging followed by adding sodium sulfide solution drop wise to the previous reaction mixture of step (e) and keeping stirring at a temperature of 70-80° C for a period of 24-26 hours, (g) transferring the final reaction mixture into Teflon(RTM: PTFE) lined stainless steel autoclave and cooking at a temperature of 180-190° C for a period in the range of 24-25 hours in muffle furnace, and (h) washing the hydrothermally treated reaction mixture of step (g) 3-4 times with acetone and drying in the vacuum oven at a temperature of 60- 70° C for a period of 12-14 hours to obtain graphene oxide complex (I), and (ii) piezoelectric device, which comprises the complex (I). The piezoelectric device is prepared by (i) preparing piezoelectric nano generator films by mixing thermoplastic polyurethane in tetrahydrofuran (THF) with dispersion of graphene oxide complex powder in THF at 70° C under constant stirring for a period of 2 hours, (ii) agitating the reaction mixture using vortex mixer and further stirring for 30 minutes at 70° C, (iii) cooling and pouring the solution onto a glass mold and drying in hood for 24 hours to obtain a film of uniform thickness, (iv) peeling off the films from mould to use in the fabrication of device, (v) cutting the films into 3 x 1 cm2pieces and applying silver paste on top and bottom of the film and drying the films at 60° C for 4 hours under vacuum, (vi) attaching the adhesive copper electrodes on both the sides, (vii) attaching thin copper wires to the copper electrodes to avoid any static charges and damage while testing, and (viii) encapsulating the device in an insulating layer. The final total solid concentration of thermoplastic polyurethane and graphene oxide complex in THF is 10 wt.% and graphene oxide complex concentrations are maintained at 5, 10 or 20 wt.% with respect to dry weight of TPU (thermoplastic polyurethane).