High efficiency perovskite light-emitting diodes of ligand-engineered colloidal formamidinium lead bromide nanoparticles

Almost ten years after the renaissance of the popular perovskite‐type semiconductors based on lead salts with the general formula AMX3 (A=organic or inorganic cation; M=divalent metal; X=halide), many facets of photophysics continue to puzzle researchers. In this Minireview, light is shed on the low mobilities of charge carriers in lead halide perovskites with special focus on the lattice properties at non‐zero temperature. The polar and soft lattice leads to pronounced electron‐phonon coupling, limiting carrier mobility and retarding recombination. We propose that the proper picture of excited charge carriers at temperature ranges that are relevant for device operations is that of a polaron, with Fröhlich coupling constants between 1<α<3. Under the aspect of light‐emitting diode application, APbX3 perovskite show moderate second order (bimolecular) recombination rates and high third‐order (Auger) rate constants. It has become apparent that this is a direct consequence of the anisotropic polar A‐site cation in organic–inorganic hybrid perovskites and might be alleviated by replacing the organic moiety with an isotropic cation.

show abstract

“…], although it has frequently been reported, [48] is not as straightforward as ar ecombination rate model ands hould be considered with care.…”

Section: Charge-carrier Generation and Recombination Kineticsmentioning

confidence: 99%

Polaronic Charge Carrier–Lattice Interactions in Lead Halide Perovskites

et al. 2017

Self Cite

View full text Add to dashboard Cite

show abstract

“…[25] ForH OIP QDs,w hich is different to II-VI and III-V semiconductor by their ionic properties,l igand exchange methods are hardly used to improve the carrier transport in HOIP QDs solid films. [26] Considering the trade-off between the stability and carriers transport of HOIP QDs films,ligand density control [27] and reducing ligand chain length [28] have been adopted to improve carrier injection and transport in HOIP QD films.H owever, owing to insulating ligands being not discarded, the dilemma of the trade-off between conductivity of QDs films and colloidal stability of QDs colloidal solution is still not fundamentally broken.Conjugated molecules or polymers can exhibit higher conductivity owing to the delocalization of the molecular electric orbitals.H erein, for the first time,w ei ntroduce an organic conjugated amine containing aC =Cgroup molecule, 3-phenyl-2-propen-1-amine (PPA), and use it as capping ligand to prepare methylamine lead bromide (MAPbBr 3 ) QDs.T aking OA ligand as reference,w ef ound the above dilemma was perfectly solved, that is,effectively improve the conductivity of MAPbBr 3 QDs films without compromising its optical property and colloidal stability by using PPAa s ligands.The conjugated PPAligands enable a22-fold increase Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.…”

mentioning

confidence: 99%

Charge Transport between Coupling Colloidal Perovskite Quantum Dots Assisted by Functional Conjugated Ligands

Dai

et al. 2018

Angew Chem Int Ed

131

View full text Add to dashboard Cite

Long alkyl-chain capping ligands are indispensable for preparing stable colloidal quantum dots. However, its insulating feature blocks efficient carrier transport among QDs, leading to inferior performance in light-emitting diodes (LEDs). The trade-off between conductivity and colloidal stability of QDs has now been overcome. Methylamine lead bromide (MAPbBr ) QDs with a conjugated alkyl-amine, 3-phenyl-2-propen-1-amine (PPA), as ligands were prepared. Owing to electron cloud overlapping and the delocalization effect of conjugated molecules, the conductivity and carrier mobility of PPA-QDs films increased almost 22 times over that of OA-QD films without compromising colloidal stability and photoluminescence. PPA-QDs LEDs exhibit a maximum current efficiency of 9.08 cd A , which is 8 times of that of OA-QDs LEDs (1.14 cd A ). This work provides critical solution for the poor conductivity of QDs in applications of energy-related devices.

show abstract

“…Based on these, many research groups have proposed RT synthesis strategies like supersaturated recrystallization (SR) and ligand-assisted precipitation (LARP). [20] Due to the different polarity of reaction solvent system, we divide RT synthesis into two aspects: polar solvent and non-polar solvent system.…”

Section: Rt Synthesismentioning

confidence: 99%

Synthesis of Colloidal Halide Perovskite Quantum Dots/Nanocrystals: Progresses and Advances

Zhao

Dong

Song

2019

Israel Journal of Chemistry

View full text Add to dashboard Cite

Colloidal halide perovskite (CHP) quantum dots (QDs)/nanocrystals (NCs) have superior optoelectronic properties, such as high optical absorption coefficient, high photoluminescence quantum yield (PLQY), tunable bandgap, composition‐related luminescence, and low manufacturing cost, which have been considered as promising low‐dimensional semiconductor materials. Profiting from these unique characteristics, CHP NCs could be widely used in various optoelectronic devices, including light‐emitting diodes (LEDs), photodetectors (PDs), solar cells (SCs), and lasers. Synthesis is the basis for the wide use of CHP NCs, which plays a vital role in the research, development and application of CHPs. Therefore, we summarize the recent synthetic strategies, and their influencing factors (e. g., the effects of ligands, and anion exchange). Besides, a summary of their optoelectronic applications is plainly mentioned. Finally, we make a brief prospect and summarize the current problems and possible solutions of this area.

show abstract

High efficiency perovskite light-emitting diodes of ligand-engineered colloidal formamidinium lead bromide nanoparticles

Cited by 206 publications

References 41 publications

Polaronic Charge Carrier–Lattice Interactions in Lead Halide Perovskites

Polaronic Charge Carrier–Lattice Interactions in Lead Halide Perovskites

Charge Transport between Coupling Colloidal Perovskite Quantum Dots Assisted by Functional Conjugated Ligands

Synthesis of Colloidal Halide Perovskite Quantum Dots/Nanocrystals: Progresses and Advances

Contact Info

Product

Resources

About