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They further fine-tuned the film's composite dynamics, leading to high-efficiency quasi-2D perovskite green LEDs with an effective area of 9.0 cm 2. An external quantum efficiency (EQE) of 16.4% was attained at <n> = 3, making it the most efficient large-area perovskite LED. Moreover, a luminance of 9.1×104 cd/m 2 was achieved in the <n> = 10 ...
As the length of the 2D organic ion increases, the spacing between the corner sharing octahedra does as well, forming a 2D or quasi-2D structure. [30] The organic and inorganic layers are held together by van der waals forces. A formula of R 2 A n−1 B n X 3n+1 is used to characterize the 2D and quasi 2D structures. [30]
It was observed that emission from perovskite nanocrystals may be the result of a bright (optically active) triplet state. [30] Several effects have been suggested to play a role on the exciton fine structure such as electron-hole exchange interactions, [ 60 ] crystal field and shape anisotropy, [ 61 ] [ 62 ] as well as the Rashba effect.
The main obstacle to viable tin perovskite solar cells is the instability of tin's oxidation state Sn 2+, which is easily oxidized to the stabler Sn 4+. [21] In solar cell research, this process is called self-doping, [22] because the Sn 4+ acts as a p-dopant and reduces solar cell efficiency.
Perovskite (pronunciation: / p ə ˈ r ɒ v s k aɪ t /) is a calcium titanium oxide mineral composed of calcium titanate (chemical formula Ca Ti O 3).Its name is also applied to the class of compounds which have the same type of crystal structure as CaTiO 3, known as the perovskite structure, which has a general chemical formula A 2+ B 4+ (X 2−) 3. [6]
A perovskite is a crystalline material of formula ABX 3 with a crystal structure similar to that of the mineral perovskite, this latter consisting of calcium titanium oxide (CaTiO 3). [2] The mineral was first discovered in the Ural mountains of Russia by Gustav Rose in 1839 and named after Russian mineralogist L. A. Perovski (1792–1856).
However, one finds a low-temperature quasi-ordered phase with a correlation function (see statistical mechanics) that decreases with the distance like a power, which depends on the temperature. The transition from the high-temperature disordered phase with the exponential correlation to this low-temperature quasi-ordered phase is a Kosterlitz ...
Dynamic light scattering (DLS) is a technique in physics that can be used to determine the size distribution profile of small particles in suspension or polymers in solution. [1] In the scope of DLS, temporal fluctuations are usually analyzed using the intensity or photon autocorrelation function (also known as photon correlation spectroscopy ...