Hjorthhoff4640

A large number of nonadiabatic dynamical studies have been applied to reveal the nature of carrier transport in organic semiconductors with different approximations. We present here a "nearly exact" graphical-process-unit-based finite-temperature time-dependent density matrix renormalization group (TD-DMRG) method to evaluate the carrier mobility in organic semiconductors, as described by the electron-phonon model, in particular, in rubrene crystal, one of the prototypical organic semiconductors, with parameters derived from first-principles. We find that (i) TD-DMRG is a general and robust method that can bridge the gap between hopping and band pictures, covering a wide range of electronic coupling strengths and (ii) with realistic parameters, TD-DMRG is able to account for the experimentally observed "band-like" transport behavior (∂μ/∂T less then 0) in rubrene. We further study the long-standing puzzle of the isotope effect for charge transport and unambiguously demonstrate that the negative isotope effect (∂μ/∂m less then 0 where m is the atomic mass) should be universal.Reaction of [Li(THF)]4[L] (L = Me8-calix[4]pyrrole]) with 0.5 equiv of [UVIO2Cl2(THF)2]2 results in formation of the oxidized calix[4]pyrrole product, [Li(THF)]2[LΔ] (1), concomitant with formation of reduced uranium oxide byproducts. Complex 1 can also be generated by reaction of [Li(THF)]4[L] with 1 equiv of I2. We hypothesize that formation of 1 proceeds via formation of a highly oxidizing cis-uranyl intermediate, [Li]2[cis-UVIO2(calix[4]pyrrole)]. To test this hypothesis, we explored the reaction of 1 with either 0.5 equiv of [UVIO2Cl2(THF)2]2 or 1 equiv of [UVIO2(OTf)2(THF)3], which affords the isostructural uranyl complexes, [Li(THF)][UVIO2(LΔ)Cl(THF)] (2) and [Li(THF)][UVIO2(LΔ)(OTf)(THF)] (3), respectively. In the solid state, 2 and 3 feature unprecedented uranyl-η5-pyrrole interactions, making them rare examples of uranyl organometallic complexes. In addition, 2 and 3 exhibit some of the smallest O-U-O angles reported to date (2 162.0(7) and 162.7(7)°; 3 164.5(5)°). Importantly, the O-U-O bending observed in these complexes suggests that the oxidation of [Li(THF)]4[L] does indeed occur via an unobserved cis-uranyl intermediate.Two-dimensional ferroelectrics is attractive for synaptic device applications because of its low power consumption and amenability to high-density device integration. Here, we demonstrate that tin monosulfide (SnS) films less than 6 nm thick show optimum performance as a semiconductor channel in an in-plane ferroelectric analogue synaptic device, whereas thicker films have a much poorer ferroelectric response due to screening effects by a higher concentration of charge carriers. The SnS ferroelectric device exhibits synaptic behaviors with highly stable room-temperature operation, high linearity in potentiation/depression, long retention, and low cycle-to-cycle/device-to-device variations. The simulated device based on ferroelectric SnS achieves ∼92.1% pattern recognition accuracy in an artificial neural network simulation. By switching the ferroelectric domains partially, multilevel conductance states and the conductance ratio can be obtained, achieving high pattern recognition accuracy.Organic-inorganic hybrid halide perovskites are promising semiconductors with tailorable optical and electronic properties. The choice of A-site cation to support a three-dimensional (3D) perovskite structure AMX3 (where M is a metal and X is a halide) is limited by the geometric Goldschmidt tolerance factor. However, this geometric constraint can be relaxed in two-dimensional (2D) perovskites, providing us an opportunity to understand how various A-site cations modulate the structural properties and thereby the optoelectronic properties. Here, we report the synthesis and structures of single-crystal (BA)2(A)Pb2I7 where BA = butylammonium and A = methylammonium (MA), formamidinium (FA), dimethylammonium (DMA), or guanidinium (GA), with a series of A-site cations varying in size. Single-crystal X-ray diffraction reveals that the MA, FA, and GA structures crystallize in the same Cmcm space group, while the DMA imposes the Ccmb space group. selleck products We observe that as the A-site cation becomes larger, the Pb-I bond continuously elongates, expanding the volume of the perovskite cage, equivalent to exerting "negative pressure" on the perovskite structures. Optical studies and DFT calculations show that the Pb-I bond length elongation reduces the overlap of the Pb s- and I p-orbitals and increases the optical bandgap, while Pb-I-Pb tilting angles play a secondary role. Raman spectra show lattice softening with increasing size of the A-site cation. These structural changes with enlarged A cations result in significant decreases in photoluminescence intensity and lifetime, consistent with a more pronounced nonradiative decay. Transient absorption microscopy results suggest that the PL drop may derive from a higher concentration of traps or phonon-assisted nonradiative recombination. The results highlight that extending the range of Goldschmidt tolerance factors for 2D perovskites is achievable, enabling further tuning of the structure-property relationships in 2D perovskites.Rhenium disulfide (ReS2) which possessed a unique direct band gap from bulk to monolayer played a very important role in the establishing optoelectronic devices, while the rapid recombination of electron-hole pair might hinder its further applications. Therefore, in order to improve its photocurrent performance, a bimetallic co-chamber feeding atomic layer deposition (ALD) with a precise dose regulation strategy was used to fabricate MoS2-ReS2 heterojunctions with controllable Mo-to-Re ratio in this work. Furthermore, because of the controlled addition of Mo atoms, the electron transfer capacity, carrier mobility and photocurrent response of these heterojunctions were significantly improved, among which the sample obtained under 100 super cycles (one super cycle for this sample consists of the followings in turn 1 ReCl5 pulse, 1 H2S pulse, 1 ReCl5 pulse and 1 MoCl5 pulse, 1 H2S pulse, the real Mo-to-Re ratio Rr=57.9%) exhibited the best photocurrent response. Due to the significant improvement in optoelectronic performance, photoelectrochemical (PEC) biosensor with the basis of the above optimized sample could achieve ultrasensitive detection of cancer-related miRNA-21 ranging from 10 aM to 1 nM with a low detection limit of 2.