| 1. |
- Wang, Nana, et al.
(författare)
-
Perovskite light-emitting diodes based on solution-processed self-organized multiple quantum wells
- 2016
-
Ingår i: Nature Photonics. - : NATURE PUBLISHING GROUP. - 1749-4885 .- 1749-4893. ; 10:11, s. 699-
-
Tidskriftsartikel (refereegranskat)abstract
- Organometal halide perovskites can be processed from solutions at low temperatures to form crystalline direct-bandgap semiconductors with promising optoelectronic properties(1-5). However, the efficiency of their electroluminescence is limited by non-radiative recombination, which is associated with defects and leakage current due to incomplete surface coverage(6-9). Here we demonstrate a solution-processed perovskite light-emitting diode (LED) based on self-organized multiple quantum wells (MQWs) with excellent film morphologies. The MQW-based LED exhibits a very high external quantum efficiency of up to 11.7%, good stability and exceptional highpower performance with an energy conversion efficiency of 5.5% at a current density of 100 mA cm(-2). This outstanding performance arises because the lower bandgap regions that generate electroluminescence are effectively confined by perovskite MQWs with higher energy gaps, resulting in very efficient radiative decay. Surprisingly, there is no evidence that the large interfacial areas between different bandgap regions cause luminescence quenching.
|
|
| 2. |
- Asokan, Vijayshankar, 1984, et al.
(författare)
-
Growth of 'W' doped molybdenum disulfide on graphene transferred molybdenum substrate
- 2018
-
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322 .- 2045-2322. ; 8:1
-
Tidskriftsartikel (refereegranskat)abstract
- In the present study, a novel method has been carried out to grow tungsten (W) doped molybdenum disulfide (MoS 2 ) on the graphene transferred TEM grid in a chemical vapor deposition (CVD) setup. Tungsten trioxide (WO 3 ) has been used as a source for 'W' while 'Mo' has been derived from Mo based substrate. Different experimental parameters were used in this experiment. Higher gas flow rate decreases the size of the sample flake and on other side increases the dopant concentrations. The interaction mechanism between Mo, S, W and oxygen (O) have been explored. The influence of oxygen seems to be not avoidable completely which also imposes effective growth condition for the reaction of Mo with incoming sulfur atoms. The difference in the migration energies of Mo, WO 3 , S clusters on the graphene and the higher reactivity of Mo clusters over other possibly formed atomic clusters on the graphene leads to the growth of W doped MoS 2 monolayers. Formation of MoS 2 monolayer and the nature of edge doping of 'W' is explained well with the crystal model using underlying nucleation principles. We believe our result provide a special route to prepare W doped MoS 2 on graphene substrate in the future.
|
|
