In the pursuit to better understand mechanisms of perovskite solar cells we performed Raman and photoluminescence measurements free-standing CH3NH3PbI3 films, comparing dark with working conditions. The grown on a glass substrate sealed by thin coverslip, were measured subsequent white-light pretreatments. extremely slow changes observe in both cannot be regarded as electronic processes, which are much faster. Thus, most probable explanation is photoinduced structural changes. transformation...

With solar conversion efficiencies surpassing 20%, organometallic perovskites show tremendous promise for cell technology. Their high brightness has also led to demonstrations of lasing and power-efficient electroluminescence. Here we that thin films methylammonium lead iodide, prepared by solution processing at temperatures not exceeding 100 °C, exhibit a highly nonlinear intensity-dependent refractive index due changes in the free-carrier concentration femtosecond excitation higher...

All-oxide-based photovoltaics (PVs) encompass the potential for extremely low cost solar cells, provided they can obtain an order of magnitude improvement in their power conversion efficiencies. To achieve this goal, we perform a combinatorial materials study metal oxide based light absorbers, charge transporters, junctions between them, and PV devices. Here report development internal quantum efficiency (IQE) method. IQE measures associated with separation collection processes, thus is...

Hybridized polaritons are generated by simultaneously coupling two vibrational modes of different organic materials to the resonance a low-loss infrared optical microcavity. A thin film poly methyl methacrylate with solvent molecules dimethylformamide trapped inside provided spectrally narrow, closely spaced carbonyl stretches absorption peaks at 1731 and 1678 cm(-1). Situating this in microcavity based on Ge/ZnS distributed Bragg reflector mirrors produced three distinct polariton branches...

Among the most reliable techniques for exfoliation of two-dimensional (2D) layered materials, sonication-assisted liquid-phase (LPE) is considered as a cost-effective and straightforward method preparing graphene its 2D inorganic counterparts at reasonable sizes acceptable levels defects. Although there were rapid advances in this field, effect outcome sonication frequency are poorly understood often ignored, resulting low efficiency. Here, we demonstrate that simple mild bath higher power...

Abstract Sb 2 Se 3 has emerged as an important photoelectrochemical (PEC) and photovoltaic (PV) material due to its rapid rise in photoconversion efficiencies. However, a complex defect chemistry, which reduces the maximum photovoltage. Thus, it is understand these defects develop passivation strategies . A comprehensive investigation of charge carrier dynamics influence sulfur treatment on optoelectronic properties performed using time‐resolved microwave conductivity (TRMC),...

We investigate the incoherent diffusion of excitons in thin films ($5.1\ifmmode\pm\else\textpm\fi{}0.1\text{ }\text{nm}$ thick) a highly absorbing J-aggregated cyanine dye material (${10}^{6}\text{ }{\text{cm}}^{\ensuremath{-}1}$ absorption constant) as excitonic component polariton microcavity. Under high-intensity pulsed laser excitation, molecular exhibit significant exciton-exciton annihilation, indicating large exciton radius more than 100 nm. When is strongly coupled to cavity,...

We describe the design, fabrication, and characterization of mechanically stable, reproducible, highly reflecting distributed Bragg reflectors (DBR) composed thermally evaporated thin films calcium fluoride (CaF2) zinc sulfide (ZnS). CaF2 ZnS were chosen as low high refractive index components multilayer DBR structures, with n = 1.43 2.38 respectively, because neither material requires substrate heating during deposition process in order to produce optical quality films. DBRs consisting...

Microcavity devices exhibiting strong light‐matter coupling in the mid‐infrared spectral range offer potential to explore exciting open physical questions pertaining energy transfer between heat and light can lead a new generation of efficient wavelength tunable sources coherent based on polariton Bose‐Einstein Condensation. Vibrational transitions organic molecules, which often have absorption peaks infrared considerably narrower linewidths than excitonic resonances, generate polaritonic...

The low-frequency vibrational (LFV) modes of biomolecules reflect specific intramolecular and intermolecular thermally induced fluctuations that are driven by external perturbations, such as ligand binding, protein interaction, electron transfer, enzymatic activity. Large efforts have been invested over the years to develop methods access LFV due their importance in studies mechanisms biological functions biomolecules. Here, we present a method measure based on Raman spectroscopy combines...

An open microcavity (OMC) is an optical system that composed of two mirrors, where one fixed and the second on a movable stage. OMCs enable tuning resonances insertion different materials between mirrors are therefore large scientific interest due to their many potential applications. Strong light–matter coupling vibrational transitions organic molecules with modes generates new polaritonic states in mid-infrared (mid-IR) spectral region. Here we achieve strong mid-IR using low optical-loss...

We present a new method for differentiating racemic crystals from enantiopure crystals. Recently, developments in optical filters have enabled the facile use of Raman spectroscopy to detect low-frequency vibrational (LFV) modes. Here, first time, we characterize LFV modes crystalline organic materials composed chiral molecules. The LF-Raman spectra and exhibit significant variation, which attribute different hydrogen-bond networks crystal structures. Across representative set amino acids,...

Pulsed laser deposition (PLD) is widely used in combinatorial material science, as it enables rapid fabrication of different composite materials. Nevertheless, this method was usually limited to small substrates, since PLD on large substrate areas results severe lateral inhomogeneity. A few technical solutions for problem have been suggested, including the use designs masks, which were meant prevent inhomogeneity thickness, density, and oxidation state a layer, while only composition allowed...

The structural instability of organometal halide perovskites (OHP) is one the major issues concerning commercialization perovskite solar cells. Probing this intrinsic milestones and challenging tasks toward enhancing lifespan material. Here we have incorporated Cs ions into methylammonium lead iodide (MAPbI3) films studied thin film optical properties. Incorporation MAPbI3 leads to formation both α-CsPbI3 ∂-CsPbI3 phases, black yellow, respectively, as indicated by evolution band edge X-ray...

In this paper, we demonstrated a method to super-resolved Raman spectroscopy, which improves the resolution of pure silicon spectra. Experimental investigations were carried out on spectra silicon. A tunable Fabry–Perot (F-P) filter was added classical setup in measuring for different states F-P coupled with decoded experimental results yielded spectrum higher having reduced linewidth spectrum. Therefore, can be very helpful improving detection material nanostructures using low spectroscopy system.

Coordination polymers (CPs) and coordination network solids such as metal-organic frameworks (MOFs) have gained increasing interest during recent years due to their unique properties potential applications. Preparing 3D printed structures using CP would provide many advantages towards utilization in fields catalysis sensing. So far, functional were mostly by dispersing pre-synthesized particles of CPs MOFs within a polymerizable carrier. This resulted active material dispersed polymeric...

We demonstrate an unexpected tenfold reduction in the lasing threshold of organic vertical microcavity under subpicosecond optical excitation. In contrast to conventional theory lasing, we find that depends on rate at which excitons are created rather than total energy delivered within exciton lifetime. The is discussed context microcavity-enhanced super-radiant coupling between excitons. interpretation super-radiance supported by temporal relaxation dynamics emission, follows time cavity...

Abstract The pharmaceutical industry is in need of new techniques to identify the chirality solids due regulatory and safety concerns regarding biological activity enantiomers. In this study, we present for first time application low‐frequency Raman spectroscopy as a sensitive method analyzing chiral purity crystals. Using method, were able small amounts, low 1 % w/w, an enantiomer racemic To demonstrate capabilities used model system based on crystals enantiopure, their mixtures various...

Rapid and accurate Gram differentiation is paramount as the first step of pathogen identification antibiotics administration. However, current method requires additional reagents, time-consuming, operator dependent. Here we show principle tip enhanced Raman spectroscopy (TERS) can differentiate between negative positive species, by detecting changes in tip-enhancement scattering from bacteria's lipid-bilayer membrane, which specifically enhances bacteria.

We synthesized millimeter-tall, dense carpets of crystalline CNTs on nonpolished copper substrates with a thin Al2O3 (below 10 nm) underlayer and Fe (1.2 layer as catalyst using chemical vapor deposition (CVD). Preheating the hydrocarbon precursor gases in-situ formation controlled amounts water were critical process parameters. High-resolution microscopy showed that lengths up to millimeter. Electrical conduction between substrate was demonstrated multiple methods (probe station,...

ABSTRACT In this paper, we present a method for "super-resolved" Raman spectroscopy which improves the resolution of obtained spectra. Experimental investigations were carried out on spectra toluene and toluene–chlorobenzene mixture. A tunable Fabry–Perot filter is added to detection channel by measuring several states spectrum higher can be after decoding process. We demonstrate both reduced linewidth in pure partial separation two overlapping peaks