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The research in circularly polarized luminescence has attracted wide interest in recent years. Efforts on one side are directed toward the development of chiral materials with both high luminescence efficiency and dissymmetry factors, and on the other side, are focused on the exploitations of these materials in optoelectronic applications. This review summarizes the recent frontiers (mostly within five years) in the research in circularly polarized luminescence, including the development of chiral emissive materials based on organic small molecules, compounds with aggregation-induced emissions, supramolecular assemblies, liquid crystals and liquids, polymers, metal-ligand coordination complexes and assemblies, metal clusters, inorganic nanomaterials, and photon upconversion systems. In addition, recent applications of related materials in organic light-emitting devices, circularly polarized light detectors, and organic lasers and displays are also discussed.

Flexible laser display is a critical component for an information output port in next-generation wearable devices. So far, the lack of appropriate display panels capable of providing sustained operation under rigorous mechanical conditions impedes the development of flexible laser displays with high reliability. Owing to the multiple scattering feedback mechanism, random lasers render high mechanical flexibility to withstand deformation, thus making them promising candidates for flexible display planes. However, the inability to obtain pixelated random laser arrays with highly ordered emissive geometries hinders the application of flexible laser displays in the wearable device. Here, for the first time, we demonstrate a mass fabrication strategy of full-color random laser arrays for flexible display panels. The feedback closed loops can be easily fulfilled in the pixels by multiple scatterings to generate durative random lasing. Due to the sustained operation of random laser, the display performance was well-maintained under mechanical deformations, and as a result, a flexible laser display panel was achieved. Our finding will provide a guidance for the development of flexible laser displays and laser illumination devices.

Lenticular printing technique provides a promising way to realize stereoscopic displays, especially, when microscopic optical structures are integrated into light-emitting materials/devices. Here, we fabricated large-area periodic structures with a spatial resolution at a wavelength scale from hybrid perovskite materials via a space-confined solution growth method. It takes advantages of both high refractive index contrast and high luminescence brightness, which allows the optical modulation on not only the reflection of illumination, but also the light emission from hybrid perovskites. The distributed feedback within these periodic structures significantly improves the degree of polarization and directionality of laser actions while their threshold is also reduced. These findings enable us to present a prototype of lenticular printing laser displays that vary emission colors at different view angles, which may find applications in creating high-resolution and high-contrast holographical images.

Surface plasmon polaritons (SPPs) are crucial for the development of next generation information and communication technologies. However, the ohmic losses inherent to all plasmonic devices seriously limit their practical application in on-chip photonic communications. Here, loss compensation of SPPs and their application in photonic logic processing was demonstrated in rationally designed organic/silver nanowire heterostructures. The heterostructures were synthesized by inserting silver nanowires (AgNWs) into crystalline organic microwires, which served as a microscale optical gain medium. These heterostructures with large organic/metal interfacial areas ensured the efficient energy transfer from excitons to SPPs. Gain for subwavelength SPPs in the heterostructure was achieved through stimulated emission of strongly confined SPPs. Furthermore, cascade gain was performed to realize basic nanoscale photonic devices, such as Boolean logic units. The results would pave an alternative avenue to incorporating SPP-enhanced devices into hybrid photonic circuitry.

The hydraulic conductivity and chemical compatibility of bentonite slurry for grouting walls were evaluated. Bentonite slurry of different concentrations and volumes was injected into fine-sand, medium-sand and coarse-sand aquifers. The results indicated that bentonite slurry was a fast and highly efficient grouting material. After injection into aquifers, a low-permeability zone could be formed immediately near the injection point. Through 24 groups of experiments, it was determined that bentonite slurry with concentrations of 6%, 7% and 10% and volumes of 0.6 PV, 0.8 PV and 0.6 PV, respectively, was required to meet the hydraulic conductivity requirement of cut-off walls for fine-sand, medium-sand and coarse-sand aquifers. In addition, the chemical compatibility of bentonite slurry was investigated to investigate its applicability as grouting wall material at waste containment facilities. Permeation with 50 mM H2SO4 solution resulted in an increase in the hydraulic conductivity by a factor of 65–73 times. The suitable pH of the bentonite slurry grouting wall ranged from 2.0 to 13.0. The hydraulic conductivity increased by a factor of approximately 4.7–54 during permeation with 10 ~ 1000 mM CaCl2. Bentonite slurry grouting walls cannot be applied in environments with salt concentrations greater than 10 mM. In contrast, permeation with 10 mM phenol solutions resulted in no appreciable change in hydraulic conductivity. Bentonite slurry grouting walls are appropriate for environments with dissolved organic pollution.

Exciton–polariton Bose–Einstein condensation (EP BEC) is of crucial importance for the development of coherent light sources and optical logic elements, as it creates a new state of matter with coherent nature and nonlinear behaviors. The demand for room temperature EP BEC has driven the development of organic polaritons because of the large binding energies of Frenkel excitons in organic materials. However, the reliance on external high-finesse microcavities for organic EP BEC results in poor compactness and integrability of devices, which restricts their practical applications in on-chip integration. Here, we demonstrate room temperature EP BEC in organic single-crystal microribbon natural cavities. The regularly shaped microribbons serve as waveguide Fabry–Pérot microcavities, in which efficient strong coupling between Frenkel excitons and photons leads to the generation of EPs at room temperature. The large exciton–photon coupling strength due to high exciton densities facilitates the achievement of EP BEC. Taking advantages of interactions in EP condensates and dimension confinement effects, we demonstrate the realization of controllable output of coherent light from the microribbons. We hope that the results will provide a useful enlightenment for using organic single crystals to construct miniaturized polaritonic devices., The use of room temperature exciton–polariton Bose–Einstein condensation is limited by the need for external high-finesse microcavities. The authors generate room temperature EPs with single-crystal microribbons as waveguide Fabry–Pérot microcavities, and demonstrate controllable output of coherent light.

The structural flexibility of hybrid perovskite materials allows for phase transition and consequently thermochromic properties. Here we investigate the thermochromic performance in a series of copper-based layered perovskites with organic cations having different alky chain lengths. Their transition temperature is found to be dependent on the organic cations due to molecular motion and hydrogen bond interaction, providing possibilities to prepare thermochromic semiconductors near room temperature for smart window applications.

The monolithic incorporation of electrical and optical components is critically important for achieving high-speed on-chip signal processing, but yet hard to satisfy the explosive growth in the demands on bandwidth and information density. Three-dimensional (3D) circuits, which are desirable for their improved performance in data handling, are ideal candidates to simultaneously promise high-capacity computing with improved speed and energy efficiency. In such highly integrated circuits, however, the selective electrical modulation of light signals is still difficult to achieve owing to the lack of controllable integration of micro-scale optical functional devices and modulation units. In this work, we demonstrate an electrically modulated microlaser module on a 3D-integrated microsystem composed of a dye-doped polymeric microcavity and an underneath microscale electrical heating circuit. The lasing mode was modulated based on electrical heating-assisted thermo-optic response of the polymeric matrices, which were further fabricated into coupled microdisks, yielding wavelength-tunable single-mode microlasers with selective electrical modulation. On this basis, a prototype of electrically controlled microlaser module with reduced signal cross-talk was achieved. The results will provide a useful enlightenment for the rational design of novel tunable optical devices with more complicated functionalities under far-field regulation, paving the way for the on-chip optoelectronic integration.

Batch experiments were designed to ascertain the morphology and valence of chromium in the reduction of hexavalent chromium with syrup under different pH conditions. Results indicated that the syrup reduced hexavalent chromium to trivalent chromium, and the existing forms of Cr were mainly Cr(OH)3, CrOOH and CrOOH–Fe. The percentage of Fe–Mn oxide-bound state was 29.28%, 29.28%, 22.22% and 20.12%, respectively, and the percentage of organic binding state was 64.71%, 66.58%, 74.74% and 73.14%, respectively, in the reaction systems at different pH (2.0, 2.5, 3.0 5.6) conditions.

Although many efforts have been attempted by scientists worldwide, electrically pumped organic lasing emission still remains as one of the greatest challenges in the field of optoelectronics. Recently, Shuai and coworkers proposed a computational strategy based on time-dependent density functional theory(TDDFT), offering a new avenue to the molecule design and materials selection towards electrically pumped organic lasers. Molecular material property prediction package(MOMAP) previously developed by this group was utilized to obtain photophysical parameters of various organic lasing molecules, and to estimate whether they can fulfill the criteria for electrical pumping. Under systematic calculation and evaluation, three compounds, BP3T, CzPVSBF, and BSBCz were screened out as promising candidates, revealing the reliability and universality of the proposed computational strategy. This work has been published online in the Nature Communications in September 8, 2020.

In this work, we chose tris(2,2′-bipyridyl)ruthenium(II)hexafluorophosphate (Ru(bpy)3(PF6)2), a metal-organic complex material, to prepare nanowires, which were subsequently applied for the construction of electrochemiluminescence (ECL) biosensor by immobilizing them onto a glassy carbon electrode (GCE) with graphene-Nafion composite films. The graphene therein, being a two-dimensional carbon nanomaterial with outstanding electronic properties, can obviously improve the conductivity of the Nafion film, as well as enhance the electrochemical signal and ECL intensity of the Ru(bpy)3(PF6)2 nanowires (RuNWs) at low graphene concentration. The developed biosensor exhibited excellent ECL stability with tripropylamine (TPrA) as co-reactant. The ECL biosensor exhibited high sensitive ECL response in a wide linear range and low detection limit for the detection of proline. It is considered that the oxidation products of proline would be responsible for the ECL enhancement. The large electro-active area of the nanowires and the enhancement effect of the graphene played critical roles in the high detection performance of the ECL biosensor. The results demonstrated herein may provide a useful enlightenment for the design of more sensitive ECL biosensors.

To understand the characteristics such as the pollutants and the sources of heavy metals in the Hunchun basin farmland soil, soil samples were collected and the contents of As, Hg, Cu, Pb, Zn, Cr, Ni, and Cd were measured. The enrichment factor (EF) was calculated. Multiple statistical analyses including correlation analysis and principal component analysis was executed. The results show that the mean contents of As Hg, Cu, Pb, Zn, Cr, Ni, and Cd were 9.09 mg kg−1, 0.06 mg kg−1, 20.17 mg kg−1, 23.34 mg kg−1, 68.25 mg kg−1, 65.02 mg kg−1, 22.91 mg kg−1, and 0.12 mg kg−1, respectively in the Hunchun basin. The values of the mean content were not above the criterion of the China Standard of Soil Environmental Quality (GB15618-1995, CSSEQ). The contents of Pb and Zn were lower than the background values of Jilin province. However, the contents of the other heavy metals exceeded the background values, particularly for Hg. More than 20% of the samples were significantly polluted by Hg, according to the EF, and less than 10% by other elements. The main sources of mercury in the Hunchun basin are artificial activity such as the lighting of coal fires by power stations and loose residents, dusts arising from coal transport, pesticides, and fertilizers. The other heavy metals reach along with the parent material in the whole area. However, in the high enrichment area, the sources of Cu, Zn, and Cd were farming, communications, and transportation; the sources of As are sewage irrigation, pesticides, and fertilizers; the sources of Pb are communication and transportation; the sources of Cr are dusts from the mining, transport, and burning of coal.

Organic contamination of groundwater is a major concern in China. However, remediation technology for groundwater contamination to address the potential harm and danger brought by the above-mentioned serious issue is still in the research stage. This study aims to improve the current research findings. In the research project, drilling, soil, and groundwater sampling and analysis were conducted in a contamination site of a petrochemical plant, migration of contaminants to the river was predicted using a numerical model, the sequence permeable reactive barrier (PRB) for treating nitrobenzene (NB) and benzene was proposed, and simulation was carried out. Research findings demonstrated that three leaking locations had been identified in the plant, the major pollutants were NB and benzene, and the groundwater contamination area was around 640000 m2. Computation results of the numerical model indicated that, in the worst case, the groundwater plume would reach the river after migration for nearly 9 years, which would endanger the safety of surface water supply. Furthermore, the two- PRB system with the filling of zero-valent iron (ZVI) and granular activated carbon attached with biofilm exerted strong remediation effects. Experimental results indicated that ZVI could transform NB to aniline effectively with a rate of approximately 93%. Meanwhile, aniline, benzene, and other organic pollutants could easily be biodegraded.

Processes that control the distribution and natural attenuation (NA) of petroleum hydrocarbons dissolved from the released diesel fuel in a bench-scale model aquifer were evaluated. The experimental results obtained in two-dimensional aqueous-phase petroleum hydrocarbon concentrations indicated that the total petroleum hydrocarbon (TPH) in the aquifer migrated in longitudinal and lateral directions. The TPH plume of 2 mg L−1 spread to the entire area of the aquifer, and the maximum concentration at the center of the plume was 44.15 mg L−1 after 90 days of release. After diesel fuel release, the NA of TPH was evaluated and quantified. Experimental data indicated that the NA of TPH was immediately implemented to prevent migration of the plume into the downgradient of the aquifer, but controlling the TPH plumes using NA mechanisms requires a long time.

To investigate the influence of illumination on the fermentative hydrogen production system, the hydrogen production efficiencies of two kinds of anaerobic activated sludge (floc and granule) from an anaerobic baffled reactor were detected under visible light, dark and light-dark, respectively. The 10 mL floc sludge or granular sludge was respectively inoculated to 100 mL diluted molasses (chemical oxygen demand of 8000 mg·L−1) in a 250 mL serum bottle, and cultured for 24 h at 37°C under different illumination conditions. The results showed that the floc was more sensitive to illumination than the granule. A hydrogen yield of 19.8 mL was obtained in the dark with a specific hydrogen production rate of 3.52 mol·kg−1MLVSS·d−1 (floc), which was the highest among the three illumination conditions. Under dark condition, the hydrogen yield of floc sludge reached the highest with the specific hydrogen production rate of 3.52 mol·kg−1MLVSS·d−1, and under light-dark, light, the specific hydrogen production rate was 3.11 and 2.21 mol·kg−1MLVSS·d−1, respectively. The results demonstrated that the illumination may affect the dehydrogenase activity of sludge as well as the activity of hydrogen-producing acetogens and then impact hydrogen production capacity.

Chemical properties and pollution of water resources were studied in the Hunchun basin, which is located in northeast China and borders directly North Korea and Russia along the Tumen river. Water quality was characterised according to its major constituents and geological features. Ground waters could generally be grouped into (Ca+Mg)-HCO3 type and (Ca+Mg)-(SO3+Cl) type in first and the second terrace areas, respectively. The mixing of these two types depends on the local conditions, such as pumping or permeability variations.

Conjugated polymers are largely intact by gamma exposure but can be energized in the presence of high-Z compounds. The resulting alteration of the polymer's high optical density and photoluminescence efficiency can be exploited for the detection of gamma radiation with high sensitivity. Diiodobenzene and conjugated polymers mix on the molecular level in solid thin films. Composite films of various thicknesses were conveniently cast from solution and exposed to gamma radiation. The responses of the films to gamma dosage were observed with dramatic changes in ultraviolet-visible absorption and photoluminescence.

High-quality, single-crystal ZnS microsprings have been made and found to have fast responses to ultraviolet light and low propagation loss. The optoelectronic properties of one-dimensional semiconductor structures such as nanowires can be modified by bending them. Now, Tianyou Zhai and colleagues in China have grown deformation-free, single-crystal ZnS microsprings by vapor deposition involving a polar-surface-driven process. They examined the optoelectronic properties of the microsprings and found that irradiation by a high-energy electron beam increases the gain while electron-electron interactions suppress the conductivity. The researchers fabricated photodetectors based on single ZnS microsprings, which exhibited a high photosensitivity and a fast response time to ultraviolet illumination. Furthermore, the microsprings had an excellent waveguide performance. These properties make ZnS microsprings promising for components for future micro/nano-optoelectronic systems.