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Short photoluminescence lifetimes in vacuum-deposited ch3nh3pbI3 perovskite thin films as a result of fast diffusion of photogenerated charge carriers
- Source :
- The Journal of Physical Chemistry Letters, RODERIC. Repositorio Institucional de la Universitat de Valéncia, instname
- Publication Year :
- 2019
-
Abstract
- It is widely accepted that a long photoluminescence (PL) lifetime in metal halide perovskite films is a crucial and favorable factor, as it ensures a large charge diffusion length leading to a high power conversion efficiency (PCE) in solar cells. It has been recently found that vacuumevaporated CH3NH3PbI3 (eMAPI) films show very short PL lifetimes of several nanoseconds. The corresponding solar cells, however, have high photovoltage (>1.1 V) and PCEs (up to 20%). We rationalize this apparent contradiction and show that eMAPI films are characterized by a very high diffusion coefficient D, estimated from modeling the PL kinetics to exceed 1 cm2/s. Such high D values are favorable for long diffusion length as well as fast transport of carriers to film surfaces, where they recombine nonradiatively with surface recombination velocity S ∼ 104 cm/s. Possible physical origins leading to the high D values are also discussed It is widely accepted that a long photoluminescence (PL) lifetime in metal halide perovskite films is a crucial and favorable factor, as it ensures a large charge diffusion length leading to a high power conversion efficiency (PCE) in solar cells. It has been recently found that vacuumevaporated CH3NH3PbI3 (eMAPI) films show very short PL lifetimes of several nanoseconds. The corresponding solar cells, however, have high photovoltage (>1.1 V) and PCEs (up to 20%). We rationalize this apparent contradiction and show that eMAPI films are characterized by a very high diffusion coefficient D, estimated from modeling the PL kinetics to exceed 1 cm2/s. Such high D values are favorable for long diffusion length as well as fast transport of carriers to film surfaces, where they recombine nonradiatively with surface recombination velocity S ∼ 104 cm/s. Possible physical origins leading to the high D values are also discussed
- Subjects :
- Materials science
Photoluminescence
UNESCO::QUÍMICA
Energy conversion efficiency
Halide
02 engineering and technology
Nanosecond
010402 general chemistry
021001 nanoscience & nanotechnology
QUÍMICA [UNESCO]
01 natural sciences
7. Clean energy
Molecular physics
0104 chemical sciences
General Materials Science
Charge carrier
Physical and Theoretical Chemistry
Thin film
Diffusion (business)
0210 nano-technology
Perovskite (structure)
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Journal :
- The Journal of Physical Chemistry Letters, RODERIC. Repositorio Institucional de la Universitat de Valéncia, instname
- Accession number :
- edsair.doi.dedup.....befd19af64626160bdd1762efa4be567