Search results
Results from the WOW.Com Content Network
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 ...
Ruddlesden-Popper (RP) phases are a type of perovskite structure that consists of two-dimensional perovskite-like slabs interleaved with cations.The general formula of an RP phase is A n+1 B n X 3n+1, where A and B are cations, X is an anion (e.g., oxygen), and n is the number of octahedral layers in the perovskite-like stack. [1]
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]
Furthermore, tolerance factors of t > 1 yield hexagonal structures (CsNiBr 3 type), and t < 0.8 result in NH 4 CdCl 3 type structures. [115] If the A-site cation is too large (t >1), but packs efficiently, 2D perovskites can be formed. [116]
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.
Light soaking for these types of cells are known to show induced efficiency under illumination and produce a ~5% efficiency improvement after light exposure for periods in the order of hours. The effect in these modules is reversible and relaxation time to the low efficiency state is found to be ~3–16 hours.
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]
Thus the electrons appear to be a 2D sheet embedded in a 3D world. ... and so is quasi-two-dimensional. ... ISBN 0-521-48148-1. References This page was ...