A novel conotoxin, -conotoxin (-BtX), has been purified and characterized from the venom of a wormhunting cone snail, Conus betulinus. The toxin, with four disulfide bonds, shares no sequence homology with any other conotoxins. Based on a partial amino acid sequence, its cDNA was cloned and sequenced. The deduced sequence consists of a 26-residue putative signal peptide, a 31-residue mature toxin, and a 13-residue extra peptide at the C terminus. The extra peptide is cleaved off by proteinase post-processing. All three Glu residues are ␥-carboxylated, one of the two Pro residues is hydroxylated at position 27, and its C-terminal residue is Pro-amidated. The monoisotopic mass of the toxin is 3569.0 Da. Electrophysiological experiments show that: 1) among voltage-gated channels, -BtX is a specific modulator of K ؉ channels; 2) among the K channels, -BtX specifically up-modulates the Ca 2؉ -and voltage-sensitive BK channels (252 ؎ 47%); 3) its EC 50 is 0.7 nM with a single binding site (Hill ‫؍‬ 0.88); 4) the time constant of wash-out is 8.3 s; and 5) -BtX has no effect on single channel conductance, but increases the open probability of BK channels. It is concluded that -BtX is a novel specific biotoxin against BK channels.

In this work, graphene-methylammonium lead iodide (MAPbI3) perovskite hybrid phototransistors fabricated by sequential vapor deposition are demonstrated. Ultrahigh responsivity of 1.73 × 107 A W−1 and detectivity of 2 × 1015 Jones are achieved, with extremely high effective quantum efficiencies of about 108% in the visible range (450–700 nm). This excellent performance is attributed to the ultra-flat perovskite films grown by vapor deposition on the graphene sheets. The hybrid structure of graphene covered with uniform perovskite has high exciton separation ability under light exposure, and thus efficiently generates photocurrents. This paper presents photoluminescence (PL) images along with statistical analysis used to study the photo-induced exciton behavior. Both uniform and dramatic PL intensity quenching has been observed over entire measured regions, consistently demonstrating excellent exciton separation in the devices.

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Graphene−semiconducting light absorber hybrid photodetectors have attracted increasing attention because of their ultrahigh photoconductive gain and superior sensitivity. However, most graphene-based hybrid photodetectors reported previously have shown a relatively long response time (on the order of seconds) caused by numerous long-lived traps in these hybrid systems, which greatly restricts device speed. In this work, graphene−thieno [3,4b]thiophene/benzodithiophene polymer hybrid photodetectors fabricated on self-assembled-monolayer (SAM)-functionalized SiO 2 substrates are demonstrated with a maximum responsivity of ∼1.8 × 10 5 A W −1 and a relatively short photocurrent response time of ∼7.8 ms. The fast and highly sensitive device characteristics provide great potential in low-light imaging applications. The hybrid photodetector on the SAM-coated SiO 2 substrate shows better performance in responsivities and response times as compared with those of the device on the bare SiO 2 substrate. The improved responsivities are attributed to a significant increase in carrier mobility in graphene channels by introducing SAM-modified substrates. In addition, SAM functionalization is capable of effectively removing multiple surface traps and charged impurities between graphene sheets and SiO 2 substrates, which prevents the long-lived trapping of photocarriers at graphene/SiO 2 interfaces and remarkably decreases device response time.

We demonstrate an alternating current (AC)-driven organic light emitting diodes (OLED) with lithium fluoride (LiF) insulating layers fabricated using simple thermal evaporation. Thermal evaporated LiF provides high stability and excellent capacitance for insulating layers in AC devices. The device requires a relatively low turn-on voltage of 7.1 V with maximum luminance of 87 cd/m2 obtained at 10 kHz and 15 Vrms. Ultraviolet photoemission spectroscopy and inverse photoemission spectroscopy are employed simultaneously to examine the electronic band structure of the materials in AC-driven OLED and to elucidate the operating mechanism, optical properties and electrical characteristics. The time-resolved luminance is also used to verify the device performance when driven by AC voltage.