Solution-processed whispering-gallery-mode microsphere lasers based on colloidal CsPbBr3 perovskite nanocrystals

Abstract Perovskite nanocrystals (NCs) have emerged as attractive gain materials for solution-processed microlasers. Despite the recent surge of reports in this feld, it is still challenging to develop low-cost perovskite NCbased microlasers with high performance. Herein, we demonstrate low-threshold, spectrally tunable lasing from ensembles of CsPbBr3 NCs deposited on silica microspheres. Multiple whispering-gallery-mode lasing is achieved from individual NC/microspheres with a low threshold of ∼3.1 µJ cm−2 and cavity quality factor of ∼1193. Through time-resolved photoluminescence measurements, electron-hole plasma recombination is elucidated as the lasing mechanism. By tuning the microsphere diameter, the desirable single-mode lasing is successfully achieved. Remarkably, the CsPbBr3 NCs display durable room-temperature lasing under ∼107 shots of pulsed laser excitation, substantially exceeding the stability of conventional colloidal NCs. These CsPbBr3 NC-based microlasers can be potentially useful in photonic applications.

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Robust single-mode lasers based on hexagonal CdS microflakes

Journal of Materials Chemistry C ◽

10.1039/d0tc02703k ◽

2020 ◽

Vol 8 (32) ◽

pp. 11201-11208

Author(s):

Yang Mi ◽

Yaoyao Wu ◽

Jinchun Shi ◽

Sheng-Nian Luo

Keyword(s):

Radiative Recombination ◽

Single Mode ◽

Whispering Gallery Mode ◽

Radiative Recombination Rate ◽

Electron Hole ◽

High Quality ◽

Time Resolved ◽

Whispering Gallery ◽

Electron Hole Plasma ◽

Time Resolved Photoluminescence

We have achieved single-mode whispering-gallery-mode lasing in CdS microflakes with sharp linewidth (∼0.12 nm) and high quality factor (∼4200). Such lasers are superior to previous CdS lasers in these lasing parameters. Through time-resolved photoluminescence measurements, electron–hole plasma recombination is established to be the lasing mechanism. The radiative recombination rate of CdS microflakes is enhanced by a factor of ∼4.7 due to the Purcell effect.

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Highly fluorescent CsPbBr3/TiO2 core/shell perovskite nanocrystals with excellent stability

SN Applied Sciences ◽

10.1007/s42452-021-04648-8 ◽

2021 ◽

Vol 3 (6) ◽

Author(s):

Haitao Chen ◽

Renhua Li ◽

Anqi Guo ◽

Yu Xia

Keyword(s):

Identical Particle ◽

Core Shell ◽

List Type ◽

Easy Method ◽

Time Resolved ◽

Perovskite Nanocrystals ◽

Promising Application ◽

The Stability ◽

Time Resolved Photoluminescence ◽

Excellent Stability

AbstractThe poor stability of CsPbX3 (X = Cl, Br, I) perovskite nanocrystals is the most impediment to its application in the field of photoelectrics. In this work, monodisperse CsPbBr3/TiO2 nanocrystals are successfully prepared by coating titanium precursor on the surface of colloidal CsPbBr3 nanocrystals at room temperature. The CsPbBr3/TiO2 nanocomposites exhibit excellent stability, remaining the identical particle size (9.2 nm), crystal structures and optical properties. Time-resolved photoluminescence decay shows that the lifetime of CsPbBr3/TiO2 nanocrystals is about 4.04 ns and keeps great stability after lasting two months in the air. Results show that the coating of TiO2 on CsPbBr3 NCs greatly suppressed the anion exchange and photodegradation, which are the main reasons for dramatically improving their chemical stability and photostability. The results provide an effective method to solve the stability problem of perovskite nanostructures and are expected to have a promising application in optoelectronic fieldsArticle highlights 1. Prepared the all-inorganic CsPbBr3/TiO2 core/shell perovskite nanocrystals by an easy method. 2. Explored its essences of PL and lifetime of the synthesized CsPbBr3/TiO2 perovskite nanocrystals. 3. CsPbBr3/TiO2 nanocrystals show the great thermal stability after the post-annealing. 4. The CsPbBr3/TiO2 nanocrystals have a high PLQY and have a promising application in solar cells.

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Optical whispering-gallery mode barcodes for high-precision and wide-range temperature measurements

Light Science & Applications ◽

10.1038/s41377-021-00472-2 ◽

2021 ◽

Vol 10 (1) ◽

Author(s):

Jie Liao ◽

Lan Yang

Keyword(s):

High Precision ◽

Dynamic Range ◽

Single Mode ◽

Whispering Gallery Mode ◽

Temperature Measurements ◽

Laser Source ◽

Multiple Modes ◽

Whispering Gallery ◽

Wide Range ◽

Thermal Sensing

AbstractTemperature is one of the most fundamental physical properties to characterize various physical, chemical, and biological processes. Even a slight change in temperature could have an impact on the status or dynamics of a system. Thus, there is a great need for high-precision and large-dynamic-range temperature measurements. Conventional temperature sensors encounter difficulties in high-precision thermal sensing on the submicron scale. Recently, optical whispering-gallery mode (WGM) sensors have shown promise for many sensing applications, such as thermal sensing, magnetic detection, and biosensing. However, despite their superior sensitivity, the conventional sensing method for WGM resonators relies on tracking the changes in a single mode, which limits the dynamic range constrained by the laser source that has to be fine-tuned in a timely manner to follow the selected mode during the measurement. Moreover, we cannot derive the actual temperature from the spectrum directly but rather derive a relative temperature change. Here, we demonstrate an optical WGM barcode technique involving simultaneous monitoring of the patterns of multiple modes that can provide a direct temperature readout from the spectrum. The measurement relies on the patterns of multiple modes in the WGM spectrum instead of the changes of a particular mode. It can provide us with more information than the single-mode spectrum, such as the precise measurement of actual temperatures. Leveraging the high sensitivity of WGMs and eliminating the need to monitor particular modes, this work lays the foundation for developing a high-performance temperature sensor with not only superior sensitivity but also a broad dynamic range.

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Whispering Gallery Mode Based Optical Fiber Sensor for Measuring Concentration of Salt Solution

Journal of Nanomaterials ◽

10.1155/2013/372625 ◽

2013 ◽

Vol 2013 ◽

pp. 1-4 ◽

Cited By ~ 4

Author(s):

Chia-Chin Chiang ◽

Jian-Cin Chao

Keyword(s):

Optical Fiber ◽

Mass Production ◽

Low Cost ◽

Optical Fiber Sensor ◽

Whispering Gallery Mode ◽

Solution Concentration ◽

Fiber Sensor ◽

Average Sensitivity ◽

Whispering Gallery ◽

The Right

An optical fiber solution-concentration sensor based on whispering gallery mode (WGM) is proposed in this paper. The WGM solution-concentration sensors were used to measure salt solutions, in which the concentrations ranged from 1% to 25% and the wavelength drifted from the left to the right. The experimental results showed an average sensitivity of approximately 0.372 nm/% and anR2linearity of 0.8835. The proposed WGM sensors are of low cost, feasible for mass production, and durable for solution-concentration sensing.

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High-performance thermoelectric silver selenide thin films cation exchanged from a copper selenide template

Nanoscale Advances ◽

10.1039/c9na00605b ◽

2020 ◽

Vol 2 (1) ◽

pp. 368-376 ◽

Cited By ~ 3

Author(s):

Nan Chen ◽

Michael R. Scimeca ◽

Shlok J. Paul ◽

Shihab B. Hafiz ◽

Ze Yang ◽

...

Keyword(s):

Thin Film ◽

Thin Films ◽

Cation Exchange ◽

High Performance ◽

Low Cost ◽

Copper Selenide ◽

Silver Selenide ◽

Solution Processed

A high-performance n-type thermoelectric Ag2Se thin film via cation exchange using a low-cost solution processed Cu2Se template.

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Fabrication, Characterization and Microsensing of Whispering-Gallery Mode Micro-Coupling Systems

Volume 13: Nano-Manufacturing Technology; and Micro and Nano Systems, Parts A and B ◽

10.1115/imece2008-66946 ◽

2008 ◽

Cited By ~ 1

Author(s):

Qiulin Ma ◽

Tobias Rossmann ◽

Zhixiong Guo

Keyword(s):

Transmission Loss ◽

Coupling Efficiency ◽

High Sensitivity ◽

Single Mode ◽

Whispering Gallery Mode ◽

Single Mode Fiber ◽

Whispering Gallery ◽

Coupling System ◽

Wide Range ◽

Micro Sensor

An optical micro-coupling system of whispering-gallery mode usually consists of a resonator (e.g. a sphere) and a coupler (e.g. a taper). In this report, silica microspheres of 50–500 μm in diameter are fabricated by hydrogen flame fusing of an end of a single mode fiber or fiber taper. Fiber tapers are fabricated by the method of heating and pulling that meets an adiabatic condition. Taper’s waist diameter can routinely be made less than 1 μm and almost zero transmission loss in a taper is achieved which allows an effective and phase-matched coupling for a wide range sizes of microspheres. Both resonators and couplers’ surface microstructure and shapes are examined by scanning electronic microscopy. Three regimes of coupling are achieved, enabling a good flexibility to control Q value and coupling efficiency of a micro-coupling system. Whispering gallery mode shift is used to demonstrate a novel temperature micro-sensor. Its sensitivity determined from actual experimental results agrees well with the theoretical value. A concept of using the photon’s cavity ring down (CRD) in the microsphere to make a novel high-sensitivity trace gas micro-sensor is proposed. The CRD time constant when ammonia is chosen as the analyte gas is predicted using the simulated absorption lines.

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High‐Quality Hexagonal Nonlayered CdS Nanoplatelets for Low‐Threshold Whispering‐Gallery‐Mode Lasing

Small ◽

10.1002/smll.201901364 ◽

2019 ◽

Vol 15 (35) ◽

pp. 1901364 ◽

Cited By ~ 10

Author(s):

Yang Mi ◽

Bao Jin ◽

Liyun Zhao ◽

Jie Chen ◽

Shuai Zhang ◽

...

Keyword(s):

Whispering Gallery Mode ◽

High Quality ◽

Whispering Gallery ◽

Low Threshold

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Silica coating enhances the stability of inorganic perovskite nanocrystals for efficient and stable down-conversion in white light-emitting devices

Nanoscale ◽

10.1039/c8nr07022a ◽

2018 ◽

Vol 10 (43) ◽

pp. 20131-20139 ◽

Cited By ~ 57

Author(s):

Fei Zhang ◽

Zhi-Feng Shi ◽

Zhuang-Zhuang Ma ◽

Ying Li ◽

Sen Li ◽

...

Keyword(s):

White Light ◽

High Performance ◽

Silica Coating ◽

White Led ◽

Light Emitting ◽

Perovskite Nanocrystals ◽

Light Emitting Devices ◽

Improved Stability ◽

The Stability ◽

Down Conversion

CsPbBr3 QDs/silica composites with substantially improved stability were applied as the color-converting layer for high-performance white LED fabrication.

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