Stabilization of halide perovskites with silicon compounds for optoelectronic,catalytic,and bioimaging applications

Silicon belongs to group 14 elements along with carbon,germanium,tin,and lead in the periodic table.Similar to carbon,silicon is capable of forming a wide range of stable compounds,including silicon hydrides,organosilicons,silicic acids,silicon oxides,and silicone polymers.These materials have been used extensively in optoelectronic devices,sensing,catalysis,and biomedical applications.In recent years,silicon compounds have also been shown to be suitable for stabilizing delicate halide perovskite structures.These composite materials are now receiving a lot of interest for their potential use in various real-world applications.Despite exhibiting outstanding performance in various optoelectronic devices,halide perovskites are susceptible to breakdown in the presence of moisture,oxygen,heat,and UV light.Silicon compounds are thought to be excellent materials for improving both halide perovskite stability and the performance of perovskite-based optoelectronic devices.In this work,a wide range of silicon compounds that have been used in halide perovskite research and their applications in various fields are discussed.The interfacial stability,structure-property correlations,and various application aspects of perovskite and silicon compounds are also analyzed at the molecular level.This study also explores the developments,difficulties,and potential future directions associated with the synthesis and application of perovskite-silicon compounds.

Enhanced photoluminescence quantum yield of MAPbBr3 nanocrystals by passivation using graphene

Diminishing surface defect states in perovskite nancx^rystals is a highly challenging subject for enhancing optoelectronic device performance.We synthesized organic/inorganic lead-halide perovskite MAPbBr3(MA=methylammonium)clusters comprising nanocrystals with diameters ranging between 20 and 30 nm and characterized an enhanced photoluminescence(PL)quantum yield(as much as^7 times)by encapsulating the MAPbBr3 with graphene(Gr).The optical properties of MAPbBr3 and Gr/MAPbBr3 were investigated by temperature-dependent micro-PL and time-resolved PL measurements.Density functional theory calculations show that the surface defect states in MAPbBr3 are removed and the optical band gap is reduced by a 0.15 eV by encapsulation with graphene due to partial restoration of lattice distortions.

Coarse and fine-tuning of lasing transverse electromagnetic modes in coupled all-inorganic perovskite quantum dots

Inorganic perovskite lasers are of particular interest,with much recent work focusing on Fabry-P6rot cavity-forming nanowires.We demonstrate the direct observation of lasing from transverse electromagnetic(TEM)modes with a long coherence time-9.5ps in coupled CsPbBr_(3) quantum dots,which dispense with an external cavity resonator and show how the wavelength of the modes can be controlled via two independent tuning-mechanisms.Controlling the pump power allowed us tofine-tune the TEM mode structure to the emission wavelength,thus providing a degree of control over the properties of the lasing signal.The temperature-tuning provided an additional degree of control over the wavelength of the lasing peak,importantly,maintained a constant full width at half maximum(FWHM)over the entire tuning range without mode-hopping.