- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Spectral Tuning of Efficient CsPbBrxCl3-x Blue Light-Emitting Diodes via Halogen Exchange Triggered by Benzenesulfonates
摘要： CsPbX3 nanocrystals (NCs)-based blue perovskite light-emitting diodes (PeLEDs) are still in a backward position while the green and red counterparts have achieved significant progress in the past few years. The emission spectrum of perovskite NCs can be manipulated via the ratio control of halides in precursor or halogen exchange of NCs. Herein, CsPbBrxCl3-x NCs are synthesized in ambient condition. With tetrabutylammonium p-toluenesulfonate (TBSA) added as the ligand during the purification process of as-synthesized perovskite NCs, bromine in NCs is substituted by chlorine and the spectrum undergoes a blue-shift, whereas chlorine is exchanged by bromine in NCs and the spectrum undergoes a red-shift by introducing sodium dodecylbenzenesulfonate (SDSA) as the ligand. The origin for halogen exchange can be attributed to the synergistic effects of anion and cation of benzenesulfonates. The photoluminescence quantum yield (PLQY) of NCs increases from 7% to 81% due to the effective passivating effects of the strong ionic sulfonate heads, and the blue PeLEDs prepared by this method show a promising external quantum efficiency (EQE) of 2.6%. Our work provides a new approach into spectral tuning of efficient blue PeLEDs.
关键词： halogen exchange,spectral tuning,blue perovskite light-emitting diodes,benzenesulfonates,CsPbX3 nanocrystals
更新于2025-09-19 17:13:59
-
Improved Charge Injection and Transport of Light-Emitting Diodes Based on Two-Dimensional Materials
摘要： Light-emitting diodes (LEDs) are considered to be the most promising energy-saving technology for future lighting and display. Two-dimensional (2D) materials, a class of materials comprised of monolayer or few layers of atoms (or unit cells), have attracted much attention in recent years, due to their unique physical and chemical properties. Here, we summarize the recent advances on the applications of 2D materials for improving the performance of LEDs, including organic light emitting diodes (OLEDs), quantum dot light emitting diodes (QLEDs) and perovskite light emitting diodes (PeLEDs), using organic ?lms, quantum dots and perovskite ?lms as emission layers (EMLs), respectively. Two dimensional materials, including graphene and its derivatives and transition metal dichalcogenides (TMDs), can be employed as interlayers and dopant in composite functional layers for high-e?ciency LEDs, suggesting the extensive application in LEDs. The functions of 2D materials used in LEDs include the improved work function, e?ective electron blocking, suppressed exciton quenching and reduced surface roughness. The potential application of 2D materials in PeLEDs is also presented and analyzed.
关键词： perovskite light emitting diodes,quantum dot light emitting diodes,organic light emitting diodes,two-dimensional materials
更新于2025-09-16 10:30:52
-
Organic composition tailored perovskite solar cells and light-emitting diodes: Perspectives and advances
摘要： Recent years have witnessed a significant performance breakthrough in both metal halide perovskite (MHP) solar cells and light-emitting diodes, but their unsatisfactory operating stabilities are still the main challenges toward commercialization. We have summarized different kinds of organic species including organic cations in MHP crystal, functional molecules in MHP polycrystalline bulk films, ligands attached on MHP quantum dots, covered polymers in composite films and encapsulants coated on devices. They assume key roles in film formation, stabilizing black phase, passivating defects, extending photoluminescence lifetime, inhibiting charge-recombination and preventing degradation. This review further examines the relationship among crystal structure, optical and electrical properties, performance and stability, revealing several irreplaceable roles of organic species in determining the performance and stability of MHP devices. Finally, we call on establishing standard stability measurements and exploring efficient encapsulation methods to improve the stabilities of MHP solar cells and LEDs, which pushes them from a promise to a production and promotes a continuous progress in this field.
关键词： Performance,Perovskite light-emitting diodes,Perovskite solar cells,Organic species,Stability
更新于2025-09-16 10:30:52
-
Highly Efficient Flexible Perovskite Light-Emitting Diodes Using Modified PEDOT:PSS Hole Transport Layer and Polymer-Silver Nanowires Composite Electrode
摘要： Metal halide perovskites have been actively studied as promising materials in optoelectronic devices because of their superior optical and electrical properties, and have also shown considerable potential for flexible devices because of their good mechanical properties. However, the large hole injection barrier and exciton quenching between the perovskite emitter and poly(3,4-ethylenedioxythiophene):poly-styrene sulfonate (PEDOT:PSS) can lead to the reduction in device efficiency. Here, a nonconductive fluorosurfactant, Zonyl FS-300 (Zonyl), is introduced into the PEDOT:PSS hole transport layer, which reduces the hole injection barrier and exciton quenching at the PEDOT:PSS/perovskite interface. Moreover, a flexible perovskite light-emitting diode with a polymer–silver nanowire composite electrode is demonstrated, showing a maximum current efficiency (CEmax) of 17.90 cd A–1, and this is maintained even after 1,000 cycles of bending with a 2.5 mm bending radius.
关键词： flexible perovskite light-emitting diodes,hole transport layer,flexible electrode,silver nanowires (AgNWs),poly(3,4-ethylenedioxythiophene):poly-styrene sulfonate (PEDOT:PSS)
更新于2025-09-16 10:30:52
-
High-Intensity CsPbBr <sub/>3</sub> Perovskite LED using Poly(bis(4-phenyl)(2,4,6-trimethylphenyl)amine) as Hole Transport and Electron-Blocking Layer
摘要： The majority of highly efficient perovskite light-emitting diodes (PeLED) contain PEDOT:PSS (poly(3,4-ethylenedioxythiophene):polystyrenesulfonate) as hole transport layer (HTL). However, the hygroscopic and acidic nature of PEDOT:PSS may lead to deterioration of PeLED performance. Moreover, due to its inferior electron-blocking properties, an additional electron-blocking layer (EBL) is required to establish charge balance and consequently obtain superior emission characteristics in typically electron-rich PeLED structures. In this work, PTAA (poly(bis(4-phenyl)(2,4,6-trimethylphenyl)amine)) serving both as HTL and EBL is employed to substitute PEDOT:PSS in PeLED. The perovskite CsPbBr3 is chosen as emissive layer (EML) material due to its high color purity and photoluminescence (PL) quantum yield. Dense CsPbBr3 films are fabricated on PTAA-coated ITO substrates by employing a one-step spin-coating approach based on nonstoichiometric perovskite precursor solutions. To suppress non-radiative recombination, a small amount of methylammonium bromide (MABr) is incorporated in the CsPbBr3 lattice. The resulting films exhibit excellent coverage and PL intensity. PeLED containing pure CsPbBr3 films as EML show a green emission with a peak at 520 nm, maximum luminance of 11,000 cd/m2, an external quantum efficiency (EQE) of 3.3 % and a current efficiency (CE) of 10.3 cd/A. Further enhancement to 21,000 cd/m2, 7.5 % and 27.0 cd/A is demonstrated by PeLED with MABr-doped CsPbBr3 layers.
关键词： PTAA,perovskite light-emitting diodes,PEDOT:PSS,electron-blocking layer,CsPbBr3,hole transport layer
更新于2025-09-16 10:30:52
-
Triplet management for efficient perovskite light-emitting diodes
摘要： Perovskite light-emitting diodes are promising for next-generation lighting and displays because of their high colour purity and performance1. Although the management of singlet and triplet excitons is fundamental to the design of efficient organic light-emitting diodes, the nature of how excitons affect performance is still not clear in perovskite2–4 and quasi-two-dimensional (2D) perovskite-based devices5–9. Here, we show that triplet excitons are key to efficient emission in green quasi-2D perovskite devices and that quenching of triplets by the organic cation is a major loss path. Employing an organic cation with a high triplet energy level (phenylethylammonium) in a quasi-2D perovskite based on formamidinium lead bromide yields efficient harvesting of triplets. Furthermore, we show that upconversion of triplets to singlets can occur, making 100% harvesting of electrically generated excitons potentially possible. The external quantum and current efficiencies of our green (527 nm) devices reached 12.4% and 52.1 cd A?1, respectively.
关键词： Perovskite light-emitting diodes,quasi-2D perovskite,external quantum efficiency,triplet excitons,organic cation
更新于2025-09-12 10:27:22
-
Efficient sky-blue perovskite light-emitting diodes via photoluminescence enhancement
摘要： The efficiencies of green and red perovskite light-emitting diodes (PeLEDs) have been increased close to their theoretical upper limit, while the efficiency of blue PeLEDs is lagging far behind. Here we report enhancing the efficiency of sky-blue PeLEDs by overcoming a major hurdle of low photoluminescence quantum efficiency in wide-bandgap perovskites. Blending phenylethylammonium chloride into cesium lead halide perovskites yields a mixture of two-dimensional and three-dimensional perovskites, which enhances photoluminescence quantum efficiency from 1.1% to 19.8%. Adding yttrium (III) chloride into the mixture further enhances photoluminescence quantum efficiency to 49.7%. Yttrium is found to incorporate into the three-dimensional perovskite grain, while it is still rich at grain boundaries and surfaces. The yttrium on grain surface increases the bandgap of grain shell, which confines the charge carriers inside grains for efficient radiative recombination. Record efficiencies of 11.0% and 4.8% were obtained in sky-blue and blue PeLEDs, respectively.
关键词： radiative recombination,perovskite light-emitting diodes,yttrium (III) chloride,photoluminescence quantum efficiency,wide-bandgap perovskites
更新于2025-09-12 10:27:22
-
Perovskite light-emitting diodes for uniform eight-segment displays
摘要： With the development of the display technology, there are higher requirements for color saturation and vividness. As a base unit, light-emitting diode (LED) has become a primary object of study. Perovskite quantum dots with high photoluminescence quantum yield, narrow emission, and wide color gamut have attracted special attention in recent years. Although LEDs based on perovskite exhibit excellent performance, there are few applications of perovskite LEDs in display. Herein, LEDs based on CsPbI3 perovskite were used as basic units for fabricating eight-segment LED displays. The LEDs exhibited a luminance of 780 cd/m2 and an external quantum efficiency of 6%. The current-density and luminance vs driving voltage confirms the uniformity of these LEDs in the eight segments, which will promote the application of perovskite nanocrystalline LEDs in the field of full color display.
关键词： Perovskite,light-emitting diodes,eight-segment displays,quantum dots,display technology
更新于2025-09-12 10:27:22
-
Efficient Quasi-Two-Dimensional Perovskite Light-Emitting Diodes with Improved Multiple Quantum Well Structure
摘要： Quasi-two-dimensional (quasi-2D) perovskites with a multiple quantum well structure can enhance the exciton binding energy and controllable quantum con?ne e?ect, which are attractive materials for e?cient perovskite light-emitting diodes (PeLEDs). However, the multiphase mixtures contained in these materials would cause nonradiative recombination at the perovskite ?lm surface. Here, a facile solution surface treatment is adopted to improve the multiple quantum well structure of the quasi-2D perovskite emitting layer, which can reduce the in?uence of defectinduced nonradiative recombination and the electric-?eld-induced dissociation of excitons for the PeLEDs. The improved multiple quantum well structure is veri?ed by UV absorption spectra and temperature-dependent photoluminescence spectra measurements. The photoluminescence quantum yield of the quasi-2D perovskite ?lm with surface treatment has been approximately increased by 200%. Meanwhile, the electroluminescence device achieves a current e?ciency of 45.9 cd/A.
关键词： electroluminescence,quasi-two-dimensional perovskite light-emitting diodes,surface treatment,multiple quantum well structure,photoluminescence quantum yield
更新于2025-09-12 10:27:22
-
Surface-modification of Cu2O nanoparticles towards band-optimized hole-injection layers in CsPbBr3 perovskite light-emitting diodes
摘要： Herein, we have proposed a strategy to grow surface-modified cuprous oxide (Cu2O) nanoparticles as an efficient hole-injecting layer (HIL) in all-inorganic cesium lead bromide (CsPbBr3) perovskite light-emitting diodes (PeLEDs). Surface of the oxide nanoparticles was modified by different ligands (thiols or silane) which in turn tailored its conduction and valence band-edge energies. As evidenced from the density of states (DOS) spectra, such modification of band-edge energies tuned the band-alignment at the perovskite-HIL interface influencing the efficiency of the PeLEDs thereby. The device performance has been correlated with the band-diagram of the heterojunctions. The report hence provides a strategy to achieve a favorable band-alignment in perovskite-based heterojunctions for optoelectronic applications.
关键词： scanning tunneling spectroscopy,Cu2O nanoparticles,band-engineering,surface-modification,perovskite light-emitting diodes.
更新于2025-09-11 14:15:04