Neodymium Chloride-Doped Perovskite Nanocrystals for Efficient Blue Light-Emitting Devices

2020 ◽  
Vol 12 (48) ◽  
pp. 53891-53898
Author(s):  
Takayuki Chiba ◽  
Jun Sato ◽  
Shota Ishikawa ◽  
Yoshihito Takahashi ◽  
Hinako Ebe ◽  
...  
Keyword(s):  
Blue Light ◽  
Light Emitting ◽  
Perovskite Nanocrystals ◽  
Light Emitting Devices ◽  
Neodymium Chloride

The Multiple Roles of Metal Ion Dopants in Spectrally Stable, Efficient Quasi‐2D Perovskite Sky‐Blue Light‐Emitting Devices

2021 ◽  
pp. 2100860
Author(s):  
Cham Heng Angus Li ◽  
Pai Geng ◽  
Sunil Benachigere Shivarudraiah ◽  
Michael Ng ◽  
Xian‐Fu Zhang ◽  
...  
Keyword(s):  
Blue Light ◽  
Metal Ion ◽  
Multiple Roles ◽  
Light Emitting ◽  
Light Emitting Devices

scholarly journals Perception of Sleep Disturbances due to Bedtime Use of Blue Light-Emitting Devices and Its Impact on Habits and Sleep Quality among Young Medical Students

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Asmaa Jniene ◽  
Leila Errguig ◽  
Abdelkader Jalil El Hangouche ◽  
Hanan Rkain ◽  
Souad Aboudrar ◽  
...  
Keyword(s):  
Medical Students ◽  
Sleep Quality ◽  
Blue Light ◽  
Sleep Disturbances ◽  
Poor Sleep ◽  
Poor Sleep Quality ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
The Mean ◽  
Perception Of Sleep

Introduction. The use of blue light-emitting devices (smartphones, tablets, and laptops) at bedtime has negative effects on sleep due to light stimulation and/or problematic excessive use. We aimed to evaluate, among young medical students, if the perception of sleep disturbances due to bedtime use of these devices is consistent with healthier habits and a better sleep quality. Materials and methods. 294 medical students in medicine and pharmacy from the Faculty of Medicine and Pharmacy of Rabat, Morocco, took part in this anonymous and voluntary cross-sectional study and answered an electronic questionnaire. Student and Mann–Whitney U tests were used to compare variables between 2 groups based on their perception of sleep disturbances. The level of significance was p≤0.05. Results. 286 students (97.3%) used a blue light-emitting smart device at bedtime before sleep, and sleep quality was poor (Pittsburgh Sleep Quality Index, PSQI > 5) in 101 students (35.3%). The perception of sleep disturbances due to this night usage was reported by 188 of them (65.7%). In this group, 154 (81.9%) used their device with all the lights turned off in the room (p=0.02), 34 (18.1%) put devices under pillows (p=0.04), 114 (60.6%) interrupted sleep to check messages (p<0.001), and the mean duration use of these technologies at bedtime was 2 h ± 23 min per night (p=0.02). Also, the mean sleep duration was 6.3 hours ± 1.25 (p=0.04), 119 (63.3%) presented fatigue on waking more than one time per week (p=0.04), and 76 (40.4%) presented poor sleep quality (75.2% of the students with PSQI > 5) (p=0.005). Conclusions. Despite the perception of sleep disturbances due to bedtime use of blue light-emitting devices, unhealthy sleep habits tend to be frequent in young medical students and worrying because it is associated to significant poor sleep quality.

Engineering Color-Stable Blue Light-Emitting Diodes with Lead Halide Perovskite Nanocrystals

2019 ◽  
Vol 11 (24) ◽  
pp. 21655-21660 ◽  
Author(s):  
Stefan T. Ochsenbein ◽  
Franziska Krieg ◽  
Yevhen Shynkarenko ◽  
Gabriele Rainò ◽  
Maksym V. Kovalenko
Keyword(s):  
Blue Light ◽  
Light Emitting Diodes ◽  
Light Emitting ◽  
Perovskite Nanocrystals ◽  
Halide Perovskite ◽  
Lead Halide

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.

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