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Detection of light in the near-to mid-infrared (IR) spectral range is a technology in demand for many applications such as optical data transmission (1.55 mm), contrast enhancement for imaging systems in foggy environments, and quality control. Most of the optoelectronic devices on the market are based on the rather expensive III-V compound technology and, as a result, the monolithic integration into the well-established and cheap silicon-based complementary metal oxide semiconductor (CMOS) production process is still an unachieved goal. Here, we report on a novel light-sensing scheme based on a silicon/fullerene-derivative heterojunction that allows the realization of optoelectronic devices for the detection of near-to mid-IR light, which is fully compatible with CMOS technology. Despite the absence of light absorption by silicon and the fullerene-derivative in the IR. a heterojunction of these materials absorbs and generates a photocurrent (PC) in the near-to mid-IR. In this spectral range it is proposed that the IR PC is caused by an interfacial absorption mechanism.In essence, an inherent disadvantage of silicon for optoelectronic IR applications is its transparency beyond a wavelength of 1.1 mm. To overcome this disadvantage, several technologies such as the heteroepitaxial growth of (polycrystalline) germanium on silicon [1][2][3] or the usage of near-IR (NIR)-photoconductive and soluble nanoparticles have been developed. [4,5] In the latter case, the facile solution processing of a guest material to the silicon-based host is of particular interest. [5] In this work, the soluble C 60 derivative methano-fullerene [6,6] phenyl-C61 butyric acid methyl ester (PCBM) as guest material has been chosen (see inset of Fig. 1, where the chemical structure is depicted). In contrast to pristine C 60 , PCBM exhibits a solubility of up to 5 wt% in common organic solvents due to functionalization of the fullerene cage with a butyric acid methylester sidegroup. [6] For polycrystalline C 60 thin films processed into field effect devices, the electron mobility is of the order of 1 cm 2 Vs À1 [7,8] and for the spin-cast PCBM thin films it is approximately one to two orders lower in magnitude.[9] The microscopic charge-carrier mobility of PCBM is only weakly temperature dependent and a highly conductive state of PCBM under a filamented current density at 15 K has been reported. [10] In this Communication is shown that a p-Si/PCBM heterojunction features a PC for photon energies from $0.55 to 1.1 eV (2.25-1.12 mm). The investigated samples have a layered structure (Fig. 1). On top of a boron-doped p-Si wafer (boron concentration 10 15 -10 16 cm À3 ) the PCBM film is deposited by spin-coating, resulting in a PCBM film thickness of 140 nm. By thermal evaporation of Al the electrical front-and back-contacts to the PCBM thin film and to the p-Si wafer are formed. To ensure an Ohmic contact of the Al to the p-Si wafer, the Al/p-Si contact is alloyed at 580 8C in a nitrogen/hydrogen atmosphere. [11] In Figure 2, the current-density-vo...

Natural dielectrics are emerging nowadays as a niche selection of materials for applications targeting biocompatibility and biodegradability for electronics and sensors within the overall effort of scientific community to achieve sustainable development and to build environmental consciousness. The two natural resins analyzed in this study, silver fir and Rocky mountain fir demonstrate robust dielectric properties and excellent film forming capabilities, while being trap free dielectrics in high‐performance organic field effect transistors (OFETs) operating at voltages as low as 1 V. Immense research possibilities are demonstrated through the avenue of inorganic nanofillers insertions in the natural resins film, that opens the door for fabrication of very low voltage OFETs with high dielectric constant insulating layers.

This work reports a reversible braking system for micromotors that can be controlled by small temperature changes (≈5 °C). To achieve this, gated‐mesoporous organosilica microparticles are internally loaded with metal catalysts (to form the motor) and the exterior (partially) grafted with thermosensitive bottle‐brush polyphosphazenes to form Janus particles. When placed in an aqueous solution of H2O2 (the fuel), rapid forward propulsion of the motors ensues due to decomposition of the fuel. Conformational changes of the polymers at defined temperatures regulate the bubble formation rate and thus act as brakes with considerable deceleration/acceleration observed. As the components can be easily varied, this represents a versatile, modular platform for the exogenous velocity control of micromotors.

Graphical abstract