scholarly journals Octahedral distortion driven by CsPbI3 nanocrystals reaction temperature – the effects on phase stability and beyond

Nanoscale ◽  
2021 ◽  
Author(s):  
Anastasia Matuhina ◽  
G. Krishnamurthy Grandhi ◽  
Maning Liu ◽  
Jan-Henrik Smått ◽  
N. S. M. Viswanath ◽  
...  
Keyword(s):  
Reaction Temperature ◽  
Phase Stability ◽  
Room Temperature ◽  
Lead Iodide ◽  
Perovskite Nanocrystals ◽  
Octahedral Distortion

Cesium lead iodide (CsPbI3) perovskite nanocrystals (NCs) suffer from a known transformation at room temperature from their red-emitting (black) to non-emitting (yellow) phase, induced by the tilting of PbI6 octahedra....

High Performance Optoelectronic Devices Based on Bright Perovskite Nanocrystals Synthesized at Room Temperature

2018 ◽  
Author(s):  
Sotirios Christodoulou ◽  
Francesco Di Stasio ◽  
Santanu Pradhan ◽  
Inigo Ramiro ◽  
Yu Bi ◽  
...  
Keyword(s):  
High Performance ◽  
Room Temperature ◽  
Optoelectronic Devices ◽  
Perovskite Nanocrystals

Stabilizing black-phase formamidinium perovskite formation at room temperature and high humidity

Science ◽  
2021 ◽  
Vol 371 (6536) ◽  
pp. 1359-1364
Author(s):  
Wei Hui ◽  
Lingfeng Chao ◽  
Hui Lu ◽  
Fei Xia ◽  
Qi Wei ◽  
...  
Keyword(s):  
Thin Film ◽  
Room Temperature ◽  
Power Conversion ◽  
Light Stress ◽  
Continuous Light ◽  
Nanometer Scale ◽  
High Humidity ◽  
Lead Iodide ◽  
Vertically Aligned ◽  
Grown Structure

The stabilization of black-phase formamidinium lead iodide (α-FAPbI3) perovskite under various environmental conditions is considered necessary for solar cells. However, challenges remain regarding the temperature sensitivity of α-FAPbI3 and the requirements for strict humidity control in its processing. Here we report the synthesis of stable α-FAPbI3, regardless of humidity and temperature, based on a vertically aligned lead iodide thin film grown from an ionic liquid, methylamine formate. The vertically grown structure has numerous nanometer-scale ion channels that facilitate the permeation of formamidinium iodide into the lead iodide thin films for fast and robust transformation to α-FAPbI3. A solar cell with a power-conversion efficiency of 24.1% was achieved. The unencapsulated cells retain 80 and 90% of their initial efficiencies for 500 hours at 85°C and continuous light stress, respectively.

scholarly journals The dark exciton ground state promotes photon-pair emission in individual perovskite nanocrystals

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Philippe Tamarat ◽  
Lei Hou ◽  
Jean-Baptiste Trebbia ◽  
Abhishek Swarnkar ◽  
Louis Biadala ◽  
...  
Keyword(s):  
Near Infrared ◽  
Exciton State ◽  
Lead Iodide ◽  
Electron Hole ◽  
Light Emitting ◽  
Perovskite Nanocrystals ◽  
Light Emitting Devices ◽  
Optical And Electronic Properties ◽  
Wide Range ◽  
Halide Perovskites

AbstractCesium lead halide perovskites exhibit outstanding optical and electronic properties for a wide range of applications in optoelectronics and for light-emitting devices. Yet, the physics of the band-edge exciton, whose recombination is at the origin of the photoluminescence, is not elucidated. Here, we unveil the exciton fine structure of individual cesium lead iodide perovskite nanocrystals and demonstrate that it is governed by the electron-hole exchange interaction and nanocrystal shape anisotropy. The lowest-energy exciton state is a long-lived dark singlet state, which promotes the creation of biexcitons at low temperatures and thus correlated photon pairs. These bright quantum emitters in the near-infrared have a photon statistics that can readily be tuned from bunching to antibunching, using magnetic or thermal coupling between dark and bright exciton sublevels.

Thermal Analysis on Dehydroxylation of Sol-Gel Derived Zinc Doped Calcium Phosphate Powders

2015 ◽  
Vol 1115 ◽  
pp. 353-356
Author(s):  
Gunawan ◽  
I. Sopyan
Keyword(s):  
Phase Stability ◽  
Room Temperature ◽  
Sol Gel ◽  
Conversion Degree ◽  
Zn Concentration ◽  
Calculated Activation Energy ◽  
Controlling Processes ◽  
Kinetics Of ◽  
Calculated Activation ◽  
Wall Method

The dehydroxylation of Zn free and 4 mol% Zn CaP powder was investigated using thermogravimetric analysis over the range of room temperature to 1200 °C. The kinetic result of dehydroxylation of Zn free and 4 mol% Zn CaP was calculated by means of the Ozawa–Flynn–Wall method. The XRD result indicated that the amount of Zn incorporated in HA lattice influences the phase stability of HA as it decreases with an increase in Zn concentration. According to calculated activation energy and conversion degree, the kinetics of HA dehydroxylation was identified, which included four successive conversion stages kinetically controlled by different rate-controlling processes. The dehydroxylation analysis of TG/DTG data show that Zn incorporation in HA lattice influences the phase stability of HA.

The Research for Microwave Modified Vermiculite Adsorption of Zn2+

2014 ◽  
Vol 809-810 ◽  
pp. 493-499
Author(s):  
Li Fang Bao ◽  
Chen Li Wang ◽  
Jin Chuan Gu ◽  
Sheng Zhong ◽  
Rui Wang
Keyword(s):  
Reaction Time ◽  
Correlation Coefficient ◽  
Adsorption Isotherms ◽  
Reaction Temperature ◽  
Room Temperature ◽  
Adsorption Equilibrium ◽  
Adsorption Rate ◽  
Absorption Mechanism ◽  
Initial Concentration ◽  
The Impact

The impact on the adsorption of Zn2+of these factors, initial concentration, modification time, reaction time vermiculite dosage, reaction temperature and pH having, and absorption mechanism are studied . The results show that: microwave modification time 30s, reaction time 40min, modified vermiculite dosage 8g/L, reaction temperature 30°C, reaction pH 6, Zn2+ adsorption rate can reach 97.91%, adsorption isotherms of Zn2+ by microwave modified vermiculite show that the adsorption equilibrium is consistent with Langmuir curves, correlation coefficient reached to 0.997 at room temperature.

scholarly journals Direct Observation of Dynamic Symmetry Breaking above Room Temperature in Methylammonium Lead Iodide Perovskite

2016 ◽  
Vol 1 (4) ◽  
pp. 880-887 ◽  
Author(s):  
Alexander N. Beecher ◽  
Octavi E. Semonin ◽  
Jonathan M. Skelton ◽  
Jarvist M. Frost ◽  
Maxwell W. Terban ◽  
...  
Keyword(s):  
Symmetry Breaking ◽  
Direct Observation ◽  
Room Temperature ◽  
Dynamic Symmetry ◽  
Lead Iodide ◽  
Methylammonium Lead Iodide

Pressure-Tailored Band Gap Engineering and Structure Evolution of Cubic Cesium Lead Iodide Perovskite Nanocrystals

2018 ◽  
Vol 122 (17) ◽  
pp. 9332-9338 ◽  
Author(s):  
Ye Cao ◽  
Guangyu Qi ◽  
Chuang Liu ◽  
Lingrui Wang ◽  
Zhiwei Ma ◽  
...  
Keyword(s):  
Band Gap ◽  
Structure Evolution ◽  
Lead Iodide ◽  
Band Gap Engineering ◽  
Perovskite Nanocrystals
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