Graphene quantum dots (GQDs) represent a new class of quantum dots with unique properties. Doping GQDs with heteroatoms provides an attractive means of effectively tuning their intrinsic properties and exploiting new phenomena for advanced device applications. Herein we report a simple electrochemical approach to luminescent and electrocatalytically active nitrogen-doped GQDs (N-GQDs) with oxygen-rich functional groups. Unlike their N-free counterparts, the newly produced N-GQDs with a N/C atomic ratio of ca. 4.3% emit blue luminescence and possess an electrocatalytic activity comparable to that of a commercially available Pt/C catalyst for the oxygen reduction reaction (ORR) in an alkaline medium. In addition to their use as metal-free ORR catalysts in fuel cells, the superior luminescence characteristic of N-GQDs allows them to be used for biomedical imaging and other optoelectronic applications.

Flexible graphene fi ber (GF) stands for a new type of fi ber of practical importance, which integrates such unique properties as high strength, electrical and thermal conductivities of individual graphene sheets into the useful, macroscopic ensembles. GFs possess the common characteristics of fi bers like the mechanical fl exibility for textiles, while maintaining the uniqueness such as low cost, light weight, and ease of functionalization in comparison with conventional carbon fi bers. [1][2][3] Due to the extraordinary challenge to assemble two-dimensional (2D) microcosmic graphene sheets with irregular size and shape into macroscopic fi brillar confi guration, however, the success in fabrication of neat graphene fi bers only comes true recently. [1][2][3][4] In this regard, we have devised a facile one-step dimensionallyconfi ned strategy to fabricate the neat GFs by directly hydrothermally assembling graphene within glass pipeline. [ 2 , 5 ] The as-produced GFs have a density of 0.23 g/cm 3 , 7 times and 85 times lower than that of conventional carbon fi bers ( > 1.7 g/cm 3 ) and Au wire (ca. 20 g/cm 3 ), while remaining strong, fl exible, conductive, weavable and shapeable, and their engineered structures with multifunctionalities can be done readily in an in situ or post-synthesis fashion. [ 2 ] These remarkable features of GFs endow them with prominent advantages over common carbon fi ber and metal wires [ 6 ] for development of unconventional, lightweight, fl exible devices, especially in fi ber shape for wearable electronics.The fl ourishing progress of electronics in the unconventional forms has opened a new prospect of future electronics such as smart skins, human friendly devices, and fl exible/stretchable circuitries and energy devices. [7][8][9][10][11][12][13][14][15][16] This new class of electronics can conformably deform into complex, non-planar shapes under bending, stretching, compressing, twisting process while maintaining good performance, reliability and integration. Flexible energy-storage devices have attracted tremendous attentions in recent years due to their promise in integration into stretchable and wearable electronics. [ 7 , 17-23 ] In particular, supercapacitors are of signifi cant interest as energy storage devices associated with their high power density, long cycling life, and short charging time. [ 24 , 25 ] Conventional supercapacitors are heavy and bulky, targeting for the applications in electric or hybrid vehicles, and auxiliary power sources. However, the development of high-effi ciency miniaturized supercapacitor devices compatible with the fl exible and wearable electronics lags except from several recent paradigms. [26][27][28][29][30] 3D graphene structures possess notable features including highly-exposed surface areas, high electrical conductivity, and good chemical stability, and therefore they have been widely explored as electrode materials for supercapacitor applications. [31][32][33][34][35] Herein, we design and fabricate a unique allgraphene core-sheath f...

An efficient moisture-electric-energy transformation is discovered by means of establishing an oxygen functional group gradient in a graphene oxide film. The moisture variation serves as an energy source to generate electric power with an energy-conversion efficiency of up to ≈62%. Based on this finding, a prototype power generator and a self-powered respiratory monitor are demonstrated under the stimulus of the human breath.

Graphene lite: a density of (2.1 ± 0.3) mg cm(-3), the lowest to date for a graphene framework architecture, is achieved by preparing an ultralight, N-doped, 3D graphene framework (see photo of a block of the material balancing on a dandelion). Its adsorption capacity for oils and organic solvents is much higher than that of the best carbonaceous sorbents, and it is a promising electrode material for supercapacitors (484 F g(-1)) and as a metal-free catalyst for the oxygen reduction reaction.

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