There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

MicroRNA exhibits differential expression levels in cancer and can affect cellular transformation, carcinogenesis and metastasis. Although fluorescence techniques using dye molecule labels have been studied, label-free molecular-level quantification of miRNA is extremely challenging. We developed a surface plasmon resonance sensor based on two-dimensional nanomaterial of antimonene for the specific label-free detection of clinically relevant biomarkers such as miRNA-21 and miRNA-155. First-principles energetic calculations reveal that antimonene has substantially stronger interaction with ssDNA than the graphene that has been previously used in DNA molecule sensing, due to thanking for more delocalized 5s/5p orbitals in antimonene. The detection limit can reach 10 aM, which is 2.3-10,000 times higher than those of existing miRNA sensors. The combination of not-attempted-before exotic sensing material and SPR architecture represents an approach to unlocking the ultrasensitive detection of miRNA and DNA and provides a promising avenue for the early diagnosis, staging, and monitoring of cancer.

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Ultrasensitive detection of miRNA with an antimonene-based surface plasmon resonance sensor.

Metal Halide Perovskites in Quantum Dot Solar Cells: Progress and Prospects

All-inorganic CsPbI3 perovskite quantum dots have received substantial research interest for photovoltaic applications because of higher efficiency compared to solar cells using other quantum dots materials and the various exciting properties that perovskites have to offer These quantum dot devices also exhibit good mechanical stability amongst various thin-film photovoltaic technologies We demonstrate higher mechanical endurance of quantum dot films compared to bulk thin film and highlight the importance of further research on high-performance and flexible optoelectronic devices using nanoscale grains as an advantage Specifically, we develop a hybrid interfacial architecture consisting of CsPbI3 quantum dot/PCBM heterojunction, enabling an energy cascade for efficient charge transfer and mechanical adhesion The champion CsPbI3 quantum dot solar cell has an efficiency of 151% (stabilized power output of 1461%), which is among the highest report to date Building on this strategy, we further demonstrate a highest efficiency of 123% in flexible quantum dot photovoltaics

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Flexible and efficient perovskite quantum dot solar cells via hybrid interfacial architecture.

While halide perovskite allows a great versatility, the application on single absorber solar cells restrings significantly the number of available materials. In this context, CsPbI3 and FAPbI3 (FA,...

Stabilization of Black Perovskite Phase in FAPbI3 and CsPbI3

Short-Chain Ligand-Passivated Stable α-CsPbI3 Quantum Dot for All-Inorganic Perovskite Solar Cells

All-inorganic α-CsPbI3 perovskite quantum dots (QDs) are attracting great interest as solar cell absorbers due to their appealing light harvesting properties and enhanced stability due to the absence of volatile organic constituents. Moreover, ex situ synthesized QDs significantly reduce the variability of the perovskite layer deposition process. However, the incorporation of α-CsPbI3 QDs into mesoporous TiO2 (m-TiO2) is highly challenging, but these constitute the best performing electron transport materials in state-of-the-art perovskite solar cells. Herein, the m-TiO2 surface is engineered using an electron-rich cesium-ion containing methyl acetate solution. As one effect of this treatment, the solid-liquid interfacial tension at the TiO2 surface is reduced and the wettability is improved, facilitating the migration of the QDs into m-TiO2. As a second effect, Cs+ ions passivate the QD surface and promote the charge transfer at the m-TiO2/QD interface, leading to an enhancement of the electron injection rate by a factor of 3. In combination with an ethanol-environment smoothing route that significantly reduces the surface roughness of the m-TiO2/QD layer, optimized devices exhibit highly reproducible power conversion efficiencies exceeding 13%. The best cell with an efficiency of 14.32% (reverse scan) reaches a short-circuit current density of 17.77 mA cm-2, which is an outstanding value for QD-based perovskite solar cells.

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High Efficiency Mesoscopic Solar Cells Using CsPbI3 Perovskite Quantum Dots Enabled by Chemical Interface Engineering.

Multinary copper-based metal sulfide (Cu-M-S) nanocrystals (NCs) usually have high absorption coefficients and near-optimum direct band gaps, which have been considered as novel photo-absorption materials for quantum dot-sensitized solar cells (QDSCs) and hole-transport materials for perovskite solar cells (PSCs). However, the formation and phase transformation mechanisms of Cu-M-S NCs during the solution-based preparing approaches are complicated. Herein, Cu-M-S NCs, including Cu2ZnSnS4 (CZTS), Cu2SnS3 (CTS), CuInS2 (CIS), and CuSbS2 (CAS), have been synthesized through solution-based hot-injection methods. Their formation and phase transformation mechanisms have been studied in terms of the growth kinetics. An effective method has been proposed to investigate the formation mechanisms of Cu-M-S NCs. The results suggest that CZTS, CTS, and CIS NCs are formed through an inter-reaction between metal sulfides rather than the classical cation exchange reactions, and CAS NCs are formed based on the CuxS structure; these findings provide new insights into the formation of Cu-M-S NCs. In addition, the anisotropic or isotropic growth processes during the growth stage have been found to be the key issues in the formation of a zinc blende or wurtzite structure NCs, respectively, which can be controlled by tuning the relative reactivity of metal precursors.

Growth kinetics and mechanisms of multinary copper-based metal sulfide nanocrystals

Thallium isotopic compositions as tracers in environmental studies: A review.

Layered MoS2, which is treated as an alternative candidate of graphene, has attracted great attention due to its large intrinsic band gap and relatively high carrier mobility It is relatively convenient and inexpensive to prepare MoS2 through chemical synthesis route Herein, a novel solution-based hot-injection method is used to prepare MoS2 Controlling the reaction time leads to the variation of MoS2 morphologies, which present as quantum dots and nanosheets Detail studies are carried out to investigate the formation mechanism of MoS2 The results indicate that the formation of layered MoS2 nanosheets follows a bottom-up process, which includes three steps in the order of quantum dots, small pieces and large area nanosheets

Qiaohui Zhong

Papers

Short-Chain Ligand-Passivated Stable α-CsPbI3 Quantum Dot for All-Inorganic Perovskite Solar Cells

High Efficiency Mesoscopic Solar Cells Using CsPbI3 Perovskite Quantum Dots Enabled by Chemical Interface Engineering.

Growth kinetics and mechanisms of multinary copper-based metal sulfide nanocrystals

Thallium isotopic compositions as tracers in environmental studies: A review.

Morphologies controllable synthesis of MoS 2 by hot-injection method: from quantum dots to nanosheets