Cadmium-free quantum dots based violet light-emitting diodes: High-efficiency and brightness via optimization of organic hole transport layers

Lin, Qingli; Shen, Huaibin; Wang, Hongzhe; Wang, Aqiang; Niu, Jinzhong; Liu, Qian; Guo, Fang; Li, Lin Song

doi:10.1016/j.orgel.2015.06.032

Cited by 76 publications

(42 citation statements)

References 40 publications

(58 reference statements)

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“…improved the ZnSe/ZnS core shell QLEDs with a maximum EQE of 7.83 % which is much higher than the best record (1.7 %) of their Cd‐containing counterparts emitting in a similar spectral range (Figure a–e) . The current density for ZnSe/ZnS core/shell QLEDs have been promoted to 2856 cd/m 2 of maximum brightness with a narrow full width at half maximum (FWHM) less than 21 nm …”

Section: Photoelectronic Energy Conversion Applicationsmentioning

confidence: 90%

Recent Advances in Zinc‐Containing Colloidal Semiconductor Nanocrystals for Optoelectronic and Energy Conversion Applications

et al. 2019

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Colloidal semiconductor nanocrystals (NCs), especially cadmium (Cd)‐ and lead (Pb)‐containing ones, have been proved to be the promising materials for photoelectronic energy conversion applications. However, the high toxicity and cost of these materials restrict their widespread use. Zinc (Zn)‐containing colloidal semiconductor NCs are non‐/less toxic and environmentally friendly materials, manifesting in stimulating optical and electronic properties with relevance to a broad scope of applications including light‐emitting diodes (LEDs), sensors, photocatalysts, and more. In this Review, we elaborate on the shape control of Zn‐containing colloidal semiconductor NCs achieved by a variety of wet‐chemical synthetic approaches. Moreover, the formation of core‐shell, doped, and hybrid structures based on Zn‐containing colloidal semiconductor NCs allow for the optimization of their functionalities, which underpin stimulating photoelectronic energy conversion applications in quantum‐dot LEDs (QLEDs), photodetectors, and photocatalysis. Zn‐containing colloidal semiconductor NCs that combine the green chemistry with sustainable developments possess a bright future.

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Section: Photoelectronic Energy Conversion Applicationsmentioning

confidence: 90%

Recent Advances in Zinc‐Containing Colloidal Semiconductor Nanocrystals for Optoelectronic and Energy Conversion Applications

et al. 2019

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“…Over the past few years, numerous studies have focused on indium phosphide (InP), [11,12] copper indium sulfide (CIS), [13] and zinc selenide (ZnSe) [14][15][16][17][18] as replacements for Cd-based QDs. Specifically, ZnSe-based QDs are promising candidate materials for Cd-free blue QLEDs given their large bandgap (≈2.7 eV) and narrow full-width at half-maximum values (FWHM).…”

Section: Introductionmentioning

confidence: 99%

“…To resolve these issues, previous studies attempted to raise the PLQY of QDs [14] or modify the HTL to minimize the hole injection barrier. [15][16][17] However, there has been no comprehensive study of the tuning of the electrical characteristics of ZnSe QD films to settle the asymmetric carrier mobility issue. Generally, it is challenging to achieve highly efficient QLEDs by simply modifying the QD layer because this often compromises the optical and electrical characteristics; [25][26][27] the majority of previous reports therefore attempted to improve the electrical properties of the charge transport layers.…”

Section: Introductionmentioning

confidence: 99%

Highly Efficient Deep Blue Cd‐Free Quantum Dot Light‐Emitting Diodes by a p‐Type Doped Emissive Layer

Cho

Park

Shin

et al. 2020

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Environmentally friendly ZnSe/ZnS core/shell quantum dots (QDs) as an alternative blue emission material to Cd‐based QDs have shown great potential for use in next‐generation displays. However, it remains still challenging to realize a high‐efficiency quantum dot light‐emitting diode (QLED) based on ZnSe/ZnS QDs due to their insufficient electrical characteristics, such as excessively high electron mobility (compared to the hole mobility) and the deep‐lying valence band. In this work, the effects of QDs doped with hole transport materials (hybrid QDs) on the electrical characteristics of a QLED are investigated. These hybrid QDs show a p‐type doping effect, which leads to a change in the density of the carriers. Specifically, the hybrid QDs can balance electrons and holes by suppressing the overflow of electrons and improving injection of holes, respectively. These electrical characteristics help to improve device performance. In detail, an external quantum efficiency (EQE) of 6.88% is achieved with the hybrid QDs. This is increased by 180% compared to a device with pure ZnSe/ZnS QDs (EQE of 2.46%). This record is the highest among deep‐blue Cd‐free QLED devices. These findings provide the importance of p‐type doping effect in QD layers and guidance for the study of the electrical properties of QDs.

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“…Recently, hybrid polymers/inorganic nanocrystal bulk heterojunction materials have emerged as a class of electronic and optoelectronic media for a number of potential applications [1][2][3][4]. They present a special interest for both theoretical and experimental considerations [5,6].…”

Section: Introductionmentioning

confidence: 99%

Optical properties of P3HT:tributylphosphine oxide-capped CdSe nanocomposites

Benchaabane

Hamed

Lahmar³

et al. 2016

Appl. Phys. A

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The optical properties of nanocomposite layers prepared by incorporation of tributylphosphine oxide (TBPO)-capped CdSe nanocrystals (NCs) in a P3HT polymer matrix are studied using different nanocrystal concentrations. Reflection spectra analyzed through Kim oscillator model lead to the determination of optical constants such as refractive index n, extinction coefficient k, dielectric permittivity e and absorption coefficient a.Using the common Cauchy, Drude-Lorentz, Tauc and single-effective-oscillator theoretical models, we have determined the values of static refractive index n s and permittivity e s , plasma frequency x p , carrier density N, optical band gap E g and oscillator and dispersion energies E 0 and E d , respectively. It is found that TBPO-capped CdSe NCs concentration affects the optoelectronic parameters of the nanocomposite thin films. Moreover, the disorder of this hybrid system is also studied by the determination of Urbach energy, which increases with TBPO-capped CdSe concentration.

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Cadmium-free quantum dots based violet light-emitting diodes: High-efficiency and brightness via optimization of organic hole transport layers

Cited by 76 publications

References 40 publications

Recent Advances in Zinc‐Containing Colloidal Semiconductor Nanocrystals for Optoelectronic and Energy Conversion Applications

Recent Advances in Zinc‐Containing Colloidal Semiconductor Nanocrystals for Optoelectronic and Energy Conversion Applications

Highly Efficient Deep Blue Cd‐Free Quantum Dot Light‐Emitting Diodes by a p‐Type Doped Emissive Layer

Optical properties of P3HT:tributylphosphine oxide-capped CdSe nanocomposites

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