scholarly journals Slow cooling and efficient extraction of C-exciton hot carriers in MoS2 monolayer

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Lei Wang ◽  
Zhuo Wang ◽  
Hai-Yu Wang ◽  
Gustavo Grinblat ◽  
Yu-Li Huang ◽  
...  
2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Mingjie Li ◽  
Saikat Bhaumik ◽  
Teck Wee Goh ◽  
Muduli Subas Kumar ◽  
Natalia Yantara ◽  
...  

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Mingjie Li ◽  
Saikat Bhaumik ◽  
Teck Wee Goh ◽  
Muduli Subas Kumar ◽  
Natalia Yantara ◽  
...  

Abstract Hot-carrier solar cells can overcome the Shockley-Queisser limit by harvesting excess energy from hot carriers. Inorganic semiconductor nanocrystals are considered prime candidates. However, hot-carrier harvesting is compromised by competitive relaxation pathways (for example, intraband Auger process and defects) that overwhelm their phonon bottlenecks. Here we show colloidal halide perovskite nanocrystals transcend these limitations and exhibit around two orders slower hot-carrier cooling times and around four times larger hot-carrier temperatures than their bulk-film counterparts. Under low pump excitation, hot-carrier cooling mediated by a phonon bottleneck is surprisingly slower in smaller nanocrystals (contrasting with conventional nanocrystals). At high pump fluence, Auger heating dominates hot-carrier cooling, which is slower in larger nanocrystals (hitherto unobserved in conventional nanocrystals). Importantly, we demonstrate efficient room temperature hot-electrons extraction (up to ∼83%) by an energy-selective electron acceptor layer within 1 ps from surface-treated perovskite NCs thin films. These insights enable fresh approaches for extremely thin absorber and concentrator-type hot-carrier solar cells.


2019 ◽  
Vol 31 (47) ◽  
pp. 1803054 ◽  
Author(s):  
Prakriti Pradhan Joshi ◽  
Sebastian F. Maehrlein ◽  
Xiaoyang Zhu

1999 ◽  
Vol 40 (6) ◽  
pp. 251-256 ◽  
Author(s):  
Susan B. Watson ◽  
Brian Brownlee ◽  
Trevor Satchwill ◽  
E. McCauley

An efficient extraction method is needed to measure trace levels of taste and odour compounds in surface waters. This is usually accomplished by costly and involved analytical procedures. We have developed a simpler alternative, using a commercially available microextraction apparatus (SPME). With this technique we successfully monitored trace levels of some target organoleptics (unsaturated aldehydes e.g. heptadienal, nonadienal, and related compounds) which commonly cause aquatic taste and odour. We identified these compounds in culture material, and analyzed for them during the development of odourous chrysophyte blooms in two ponds. Preliminary work has also found a good recovery of some important off-flavour terpenoids (e.g. geosmin and MIB). SPME is labour and cost efficient, and therefore appealing to water treatment facilities for detection and monitoring. In addition, SPME requires only small sample volumes, and is therefore suitable for culture work.


2020 ◽  
Vol 10 (3) ◽  
pp. 206-212
Author(s):  
Vijeesh Padmanabhan ◽  
Maneesha P. Madhu ◽  
Supriya M. Hariharan

Aim: To study the temperature stability of TGS doped with ZnSO4, CdCl2, BaCl2, and compare it with that of pure TGS. Objectives: Synthesizing pure and doped TGS and studying their temperature dependence using TGA, DTA, and DSC analysis. Methods: Slow cooling solution growth was used to grow single crystals of pure and doped TGS. The TGA, DTA and DSC analysis was conducted for determining the temperature stability. Results: The thermal analysis of pure and doped TGS shows that the doped samples show a similar dependence on temperature as pure TGS. The temperature of decomposition of pure and doped samples (BTGS, ZTGS, CdTGS) was 226.60°C, 228.38°C, 229.13°C, and 239.13°C respectively. The melting onset of these samples was 214.51°C, 216.04°C, 217.69°C and 216.04°C respectively. Conclusion: The study shows that doping TGS with the above three described materials did not alter their temperature stability considerably. It is a good result as doping TGS, for varying its characteristics like absorbance, reflectance, bandgap energy, etc., which did not alter its temperature stability. Therefore, TGS doped with the above three dopants can be used at the same temperature ranges as of pure TGS but with much-improved efficiency.


2020 ◽  
Vol 251 ◽  
pp. 117327 ◽  
Author(s):  
M.N. Keddar ◽  
A. Ballesteros-Gómez ◽  
M. Amiali ◽  
J.A. Siles ◽  
D. Zerrouki ◽  
...  
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