Fabrication of nanostructured graphene (Gr) for gas sensing applications has become increasingly attractive. For the first time, 3D graphene flowers (GF) cluster patterns are grown directly on an Ni foam substrate by inexpensive homebuilt microwave plasma‐enhanced chemical vapor deposition (MPCVD) using the gas mixture H2/C2H4O2@Ar as a precursor. The interim morphologies of the synthesized GF are investigated and the growth mechanism of the GF film is proposed. The GF are decomposed to few‐layer Gr sheets by ultrasonication in ethanol. For the first time, MPCVD‐synthesized Gr is exploited to fabricate a gas sensor that exhibits an ultrahigh sensitivity of 133.2 ppm−1 to NO2. Outstanding sensor responses of 1411% and 101% to 10 ppm and 200 ppb NO2, respectively, are achieved. Furthermore, a low theoretical detection limit of 785 ppt NO2 is achieved. An ultrafast (within 2 s) recovery is observed at room temperature, and an imbedded microheater is employed to improve the selectivity of NO2 detection relative to humidity. This work represents a simple, clean, and efficient route to synthesize large‐area cauliflower Gr for gas detection with high performance, including ultrahigh sensitivity, good selectivity, fast recovery, and reversibility.

The ternary and tandem strategies are effective methods for improving the photovoltaic performance of organic solar cells (OSCs). Here an asymmetric wide-bandgap nonfullerene acceptor named AITC is synthesized. AITC with...

A new optoelectronic building block, dithieno-[3′,2′:3,4;2″,3″:5,6]benzo[1,2-c][1,2,5]thiadiazole, was designed by applying a fusion strategy on 4,7-dithienyl-2,1,3benzothiadazole (DTBT) and named as fDTBT. In combination with benzo[1,2-b:4,5-b′]dithiophene (BDT), fDTBT was used for the construction of a family of donor−acceptor copolymers, P(BDT n -fDTBT), with different side chains (n is carbon number of the side chain and varies from 8, 10, 12, 16, 20, to 24). It was found that the side chains have great impact on processing and photovoltaic properties of the polymers. P(BDT n -fDTBT) (n = 8, 10, and 12) bearing small alkyl side chains show poor solubility even in hot solvents. P(BDT n -fDTBT) (n = 20 and 24) have good solubility but inferior photovoltaic performance with an efficiency of 1.04% and 0.49%, respectively. Only P(BDT 16 -fDTBT) having 2-hexyldecyl side chain possesses both suitable solution processability and good photovoltaic properties with an efficiency around 4.36%. The comparison between P(BDT 16 -fDTBT) with the nonfused reference polymer P(BDT 20 -DTBT) reveals that the structural fusion on DTBT endows the polymer a deeper HOMO energy level and a better film morphology when blending with [6,6]-phenyl-C 61 -butyric acid methyl ester (PC 61 BM), finally resulting in improved photovoltaic performance.

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