Why Oxygen Increases Carrier Lifetimes but Accelerates Degradation of CH3NH3PbI3 under Light Irradiation: Time-Domain Ab Initio Analysis

2020 ◽  
Vol 142 (34) ◽  
pp. 14664-14673 ◽  
Author(s):  
Jinlu He ◽  
Wei-Hai Fang ◽  
Run Long ◽  
Oleg V. Prezhdo
Keyword(s):  
Ab Initio ◽  
Time Domain ◽  
Irradiation Time ◽  
Light Irradiation ◽  
Carrier Lifetimes

Strain Controls Charge Carrier Lifetimes in Monolayer WSe2: Ab Initio Time Domain Analysis

2019 ◽  
Vol 10 (24) ◽  
pp. 7732-7739 ◽  
Author(s):  
Yating Yang ◽  
Wei-Hai Fang ◽  
Alex Benderskii ◽  
Run Long ◽  
Oleg V. Prezhdo
Keyword(s):  
Charge Carrier ◽  
Ab Initio ◽  
Time Domain ◽  
Time Domain Analysis ◽  
Domain Analysis ◽  
Carrier Lifetimes

scholarly journals Influence of shade and irradiation time on the hardness of composite resins

2007 ◽  
Vol 18 (3) ◽  
pp. 231-234 ◽  
Author(s):  
Álvaro Della Bona ◽  
Vinícius Rosa ◽  
Dileta Cecchetti
Keyword(s):  
Composite Resin ◽  
Irradiation Time ◽  
Composite Resins ◽  
Light Irradiation ◽  
Hardness Tester ◽  
Different Depths ◽  
Study Hypothesis ◽  
Dark Shade

This study tested the following hypotheses: 1. increasing light irradiation time (IT) produces greater values of superficial hardness on different depths (0 and 3 mm); and 2. a dark shade composite (A3) needs longer IT than a light shade composite (A1) to produce similar hardness. Disk-shaped specimens (n=24 per shade) were fabricated using a 3-mm-thick increment of composite resin (Z100). Specimens were randomly assigned to 3 groups (n=8) according to the IT (400 mW/cm2) at the upper (U) surface: A1-10 and A3-10: 10 s; A1-20 and A3-20: 20 s; A1-40 and A3-40: 40 s. Specimens were stored in black lightproof containers at 37ºC for 24 h before indentation in a hardness tester. Three Vickers indentations were performed on the U and lower (L) surfaces of each specimen. The indent diagonals were measured and the hardness value calculated. The results were analyzed statistically by ANOVA and Tukey's test (alpha=0.05). Statistically significant differences were found between U and L surfaces of each composite shade-IT combination (p=0.0001) and among the ITs of same shade-surface combination (p=0.0001), except between groups A1-20U and A1-40U, confirming the study hypothesis 1 and partially rejecting the hypothesis 2.

scholarly journals Pb dimerization greatly accelerates charge losses in MAPbI3: Time-domain ab initio analysis

2020 ◽  
Vol 152 (6) ◽  
pp. 064707 ◽  
Author(s):  
Zhaosheng Zhang ◽  
Lu Qiao ◽  
Carlos Mora-Perez ◽  
Run Long ◽  
Oleg V. Prezhdo
Keyword(s):  
Ab Initio ◽  
Time Domain
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