Present-day liquid-state lasers are based on organic dyes. Here we demonstrate an alternative class of liquid lasers that use solutions of colloidal quantum dots (QDs). Previous efforts to realize such devices have been hampered by the fast non-radiative Auger recombination of multicarrier states required for optical gain. Here we overcome this challenge by using type-(I + II) QDs, which feature a trion-like optical gain state with strongly suppressed Auger recombination. When combined with a Littrow optical cavity, static (non-circulated) solutions of these QDs exhibit stable lasing tunable from 634 nm to 575 nm. These results indicate the feasibility of technologically viable dye-like QD lasers that exhibit broad spectral tunability and, importantly, provide stable operation without the need for a circulation system—a standard attribute of traditional dye lasers. The latter opens the door to less complex and more compact devices that can be readily integrated with various optical and electro-optical systems. An additional advantage of these lasers is the wide range of potentially available wavelengths that can be selected by controlling the composition, size and structure of the QDs.

Mesoporous silica (mSiO₂) particle-based electrorheological (ER) fluids were examined to determine the effect of the particles’ aspect ratio on ER performance. Multigram-scale mSiO₂ particles were fabricated with different aspect ratios using the sol–gel method. The ER performance of various mSiO₂ particle-based ER fluids improved with an increasing aspect ratio due to the better flow resistance and mechanical stability. Moreover, an incremental increase in the aspect ratio enhanced the interfacial polarization of the material. Thus, mSiO₂ materials with a high aspect ratio exhibited the highest ER performance due to combined contributions from geometrical effects and their dielectric properties. In addition, various mSiO₂-based ER fluids showed potential for large-scale production and a wide applicable range of electric field strengths (up to 10.0 kV mm⁻¹).

Polyaniline‐capped mesoporous carbon nanosheets with high conductivity and porosity are synthesized by vapor deposition polymerization. The mesoporous carbon template is prepared by removing ordered cubic iron oxide nanocrystals embedded in the carbon matrix obtained by thermal decomposition of an iron‐oleate complex in a sodium chloride matrix. The evaporated aniline monomers are slowly polymerized on the carbon surface pretreated with FeCl₃ as an initiator, partially filling the carbon pores to improve conductivity. The resulting products exhibit efficient hybrid energy storage mechanisms of electric double‐layer capacitance and pseudocapacitance. When the nanosheets are assembled for a symmetric supercapacitor, the device capacitance reaches 107.8 F g⁻¹, at a current density of 0.5 A g⁻¹, and a capacitance retention of 69.6% is achieved at a ten times higher current density of 5 A g⁻¹. Electrochemical impedance spectroscopy reveals that the transition from resistive to capacitive behavior occurs within 0.63 s, indicating that fast ion and charge transport results in high capacitance and rate capability. The corresponding energy and power densities are 9.59 Wh kg⁻¹ and 200.1 W kg⁻¹ at a current density of 0.5 A g⁻¹, demonstrating efficient energy storage in a symmetric supercapacitor.