Query: Transition metal ion doping perovskite nanocrystals for high luminescence quantum yield

Candidate papers:

abstract: Abstract All inorganic perovskite nanocrystals (NCs) have become a new generation of low cost semiconductor luminescent materials for optoelectronic applications due to their excellent optical properties. Prepared perovskite NCs undergo different ion doping and surface modification, which makes the NCs photo luminescence quantum yield (PLQY) basically uniform. However, stability of perovskite NCs solution in the environment has always been an important factor restricting its practical application. Here, we used melt quenching method to prepare a series of different Ni2+ doped CsPbBr3 NCs glass. Through experimental characterization and DFT calculation it is found that the entry of Ni2+ into the NCs lattice can eliminate the structural defects of NCs and improve the order of the perovskite lattice. Ni2+ doped perovskite NCs have strong band edge emission and high quantum yield (up to 84.3%
author_names: Chenyang Shen

Yi Zhao

Lin Yuan

Ling Ding

Ya Chen

Haishen Yang

Shimin Liu

Jingheng Nie

Weidong Xiang

Xiaojuan Liang
title: Transition metal ion doping perovskite nanocrystals for high luminescence quantum yield
year: 2020

abstract: The luminescence and charge transport properties of inorganic CsPbX3 perovskite nanocrystals (NCs) make them attractive candidates for various optoelectronic applications, such as lasing, X ray imaging, light communication, and light emitting diodes (LEDs) However, to realize cutting edge device performance, high quality NCs with high photoluminescence quantum yields (PLQYs) are essential. Therefore, substantial efforts and progress have been made to attain superior design/engineering and optimization of the inorganic NCs with a focus on surface quality, reduced nonradiative charge carrier recombination centers, and improved colloidal stabilities. Metal ion doping has been proven to have a robust influence on the electronic band structure, PL behavior, and charge carrier recombination dynamics. Thus, in this perspective, we summarize the recent progress of the significant impact of metal cation doping on the optical properties, including the PL enhancement of CsPbCl3, CsPbBr3, and CsPbI3 perovskite NCs. Moreover, we shed light on the mechanism behind such improved properties. We conclude by recommending possible aspects and strategies to be further explored and considered for better utilization of these doped NCs in thin film optoelectronic and energy conversion devices.
author_names: Ghada H Ahmed

Jun Yin

Osman M Bakr

Omar F Mohammed
title: Near unity photoluminescence quantum yield in inorganic perovskite nanocrystals by metal ion doping.
venue: The Journal of chemical physics
year: 2020

abstract: Metal halide perovskite nanocrystals (NCs) have attracted great attention in the fields of light emitting diodes, lasers, X ray imaging, solar cells and photoelectric detectors due to their excellent optoelectronic properties. Compared with organic inorganic hybrid perovskite NCs, all inorganic perovskite CsPbX3 (X Cl, Br, I) NCs have good photoelectric properties and high stability. To further improve the photoluminescence (PL) quantum yields (QYs) and stability of CsPbX3 NCs, researchers reduced the defects as nonradiative recombination centers in NCs by the following strategies: 1) surface treatment with different ligands; 2) control of synthesis conditions with halide rich compounds; 3) doping of metal ions. Among them, metal doping is considered as a universal and effective way to adjust the optoelectronic properties of semiconductors. It is found that the type and the concentration of metal ions have great influence on the electronic band structure and PL performance of NCs after the metal ions have been doped into CsPbX3 NCs. At the same time, compared with II VI and III V semiconductors, the unique structure of all inorganic perovskite NCs makes the doping of metal ions easier. Appropriate doping can not only enhance the intrinsic optical properties of the NCs without affecting their crystal structure, but also introduce new electronic energy levels into the NCs and new luminescent properties of doped metal ions. Based on metal ions doping strategy, the PLQYs of doped CsPbX3 NCs have been enhanced to nearly 100% In this work, we summarize recent advances in metal doping of the four typical kinds of perovskite NCs, including CsPbCl3, CsPbBr3, CsPbI3, and Mn2+ doped CsPbX3, and discuss the physical mechanisms of the improved properties through doping metal ions. It should be pointed out that the doping of some metal ions such as Ni2+ and Cd2+ into the above four kinds of NC systems can effectively passivate NC defects, thus improving the PL QY and stability of NCs. In addition, we put forward some personal perspectives on the future research subjects of interest and directions of metal doping for enhanced PL of CsPbX3 NCs, which needs to be further explored in order to promote extensive application of perovskite NCs to various optoelectronic devices.
author_names: Pengchao Yu

Sheng Cao

Ruosheng Zeng

Bingsuo Zou

Jialong Zhao
title: Advances in improved photoluminescence properties of all inorganic perovskite nanocrystals via metal ion doping
venue: Acta Physica Sinica
year: 2020

abstract: Lanthanides have been widely explored as optically active dopants in inorganic crystal lattices, which are often insulating in nature. Doping trivalent lanthanide (Ln 3+ into traditional semiconductor nanocrystals, such as CdSe, is challenging because of their tetrahedral coordination. Interestingly, CsPbX 3 (X Cl, Br, I) perovskite nanocrystals provide the octahedral coordination suitable for Ln 3+ doping. Over the last two years, tremendous success has been achieved in doping Ln 3+ into CsPbX 3 nanocrystals, combining the excellent optoelectronic properties of the host with the f f electronic transitions of the dopants. For example, the efficient quantum cutting phenomenon in Yb 3+ doped CsPb(Cl,Br) 3 nanocrystals yields a photoluminescence quantum yield close to 200% Other approaches of Ln 3+ doping and codoping have enabled promising proof of principle demonstration of solid state lighting and solar photovoltaics. In this perspective article, we highlight the salient features of the material design (including doping in Pb free perovskites) optical properties and potential optoelectronic applications of lanthanide doped metal halide perovskite nanocrystals. While review articles on doping different metal ions into perovskite nanocrystals are present, the present review type article is solely dedicated to lanthanide doped metal halide perovskite nanocrystals. Methods for integrating lanthanide materials into light emitting devices to improve their performance have been reviewed by scientists from India and China. Semiconductors create light when the energy of a high energy electron is converted to a single photon. Conventionally, the minimum energy of this photon is determined by an intrinsic material property known as the bandgap. Wasim Mir from the Indian Institute of Science Education and Research Pune, and colleagues, summarize developments in using lanthanide ions to enable the generation of lower energy light. Lanthanide ions provide an energy "step" within the bandgap that means the electron is converted to two low energy photons rather than a single high energy one. The authors review how embedding lanthanum ions within nanoparticles made from so called metal halide perovskites makes them easier to integrate into common optoelectronic semiconductors such as silicon. Metal halide perovskites are extraordinary defect tolerant semiconductors. A unique structural aspect of perovskites is the octahedral coordination for (B site) metal ions, unlike other semiconductors that exhibit tetrahedral coordination. This octahedral coordination helped to achieve lanthanide doping in halide perovskite nanocrystals in 2017. Fundamental understanding of material design, luminescence and quantum cutting phenomena in lanthanides (with focus on Yb 3+ doped in CsPbX 3 (X Cl, Br, I) and Cs 2 AgInCl 6 nanocrystals are reported. Subsequently, these doped systems are applied for solar energy harvesting and lighting in both visible and near infrared region. This perspective article summarizes everything important that has happened so far in field and discusses about the future research directions.
author_names: Wasim J Mir

Tariq Sheikh

Habibul Arfin

Zhiguo Xia

Angshuman Nag
title: Lanthanide doping in metal halide perovskite nanocrystals: spectral shifting, quantum cutting and optoelectronic applications
venue: NPG Asia Materials
year: 2020

abstract: Cesium lead halide (CsPbX3; X Cl, Br, and I) perovskite nanocrystals (PNCs) have drawn much attention toward their synthesis and optoelectronic properties, but violet emitting CsPbCl3 PNCs fall behind CsPbBr3 (green) and CsPbI3 (red) ones in terms of the photoluminescence quantum yield (PLQY) and material durability limiting their commercial use in devices. Herein, we synthesized highly stable Zn incorporated CsPbCl3 PNCs via a hot injection method and demonstrated their optical performances (PLQY) and thermal moisture photostabilities. A wide range of structural characterizations were used to demonstrate the substitution of Pb2+ sites by Zn2+ ions without altering the CsPbCl3 PNC crystal lattice. The optical measurements revealed that Zn doping had substantially improved the overall PLQY >85% at around 408 410 nm and had also enhanced the short range lattice order by eliminating intrinsic defects like halide vacancies and octahedral distortions. The Zn doped CsPbCl3 PNCs retained 49% of their initial luminescence even after annealing at 413 K and exhibited good moisture and photostability. Blue emitting Zn doped CsPb(Cl/Br)3 PNCs with a PLQY above 90% at around 445 450 nm were synthesized and blended with PMMA to use them as a color conversion layer in combination with CsPbBr3(green) and CsPb(Br/I)3 (red) @PMMA/glasses to generate white light using a commercial ultraviolet LED chip (365 nm) The designed 20 mA driven prototype white LED device displayed a bright white light with a luminous efficiency of 67.5 lm/W, a CCT of 6285 K, and a CRI of 86.3. The designed white LED device also achieved a wide color gamut of ~118% NTSC and 87% Rec. 2020.
author_names: V Naresh

Nohyun Lee
title: Zn(II) Doped Cesium Lead Halide Perovskite Nanocrystals with High Quantum Yield and Wide Color Tunability for Color Conversion Light Emitting Displays
year: 2020

abstract: Abstract Mn doped CsPbCl3 nanocrystals are considered to be a promising material for luminescence and display applications owing to Mn doping provides a way to introduce new optical properties and reduce the use of toxic Pb. Complicate ion exchange and hot injection are commonly used for the fabrication of the nanocrystals. Developing a fast and efficient synthesis method remains a challenge so far. Herein, we developed a simplified solid state mechanochemical approach to synthesize Mn doped CsPbCl3 nanocrystals and investigated the structure and luminescence properties of the as synthesized nanocrystals. Cubic morphology of Mn doped CsPbCl3 nanocrystals with average size of 13 nm have been obtained by this approach. Mn was successfully incorporated in CsPbCl3 perovskite nanocrystals, resulting in a high photoluminescence quantum yield of 40.7% with an improvement of stability. Emission peak of 594 nm that can be assigned to the luminescence of Mn2+ d d transition was observed under 365 nm UV excitation. The color of the luminescence changed from blue to warm white to yellow depended on the amount of Mn doping, exhibiting a tunable color property. It is expected that this approach provides an effective route that would help for synthesis of perovskite nanocrystals doped with different dopants.
author_names: Jianing Cheng

Ya'nan Li

Wei Feng Qu

Min Sun

Yiwen Liu

Wang-zhou Shi

Weijie Du

Yiwen Zhang
title: Mechanochemical synthesis and characterization of Mn doped CsPbCl3 perovskite nanocrystals
year: 2020

abstract: All inorganic perovskite nanocrystals (NCs) have drawn enormous attention recently for their excellent optoelectronic properties in many fields. However, their poor stability in polar solvents and at high temperatures hinders practical applications. Moreover, PbX2 (X Cl, Br or I) is employed both as lead and halide precursor in common protocols, which imposes limitations on the precise adjustment of the amount of reaction species and the composition of the final NCs. Here, we demonstrate that transition metal halides (FeX3, CoX2, NiX2, CuX2 and ZnX2; X Cl, Br or I) can be efficiently used as halide sources, which not only allows efficient control of the amount of halide precursors and emission wavelength, but also significantly improves the stability of NCs. Since the metal ions are mainly doped on the surface of NCs as ligand stabilizers, all excellent optical properties are preserved, such as high photoluminescent quantum yield and narrow full width at half maxima. Finally, by using green emitting FeBr3 assisted CsPbBr3 NCs and red emitting BaGe4O9:Eu3+ phosphors as color converters, a warm white light emitting diode (WLED) device can be fabricated, with the CIE coordinates of (0.3804, 0.3813) the color temperature of 4033 K, and luminous efficiency of 38.89 lm W 1 under a driving current of 20 mA. This device also shows potential applications in backlit displays, with a wide color gamut a National Television System Committee (NTSC) value of 125% and ITU R Recommendation B.T. 2020 (Rec. 2020) of 95%
author_names: Hongwei Ding

Weiwei Liu

Youkun Zheng

Chunmei Li

Hui Jiang

Xuemei Wang
title: Transition metal halide doped, highly stable all inorganic perovskite nanocrystals for fabrication of white light emitting diodes
year: 2019

abstract: Abstract Room temperature phase instability of cubic CsPbI3 perovskite nanocrystals is one of the notorious limitations for practical applications in optoelectronic fields. Herein, the incorporation of Ni2+ ions into CsPbI3 lattice was successfully achieved by a modified hot injection method using nickel acetate as doping precursor. The as prepared Ni2+ (3.3 mol% CsPbI3 nanocrystals exhibited an improved, near unity (95%~100% photoluminescence quantum yield owing to the enhanced radiative decay rate and the decreased non radiative decay rate. Additionally, Ni doping was demonstrated to stabilize CsPbI3 lattice and the Ni2+ CsPbI3 film and colloidal solution can retain their red luminescence up to 15 days and 7 months in atmosphere, respectively. First principle calculations verified that the significantly improved optical performance and stability of Ni2+ CsPbI3 nanocrystals arose primarily from the increased formation energy due to the successful doping of Ni2+ in CsPbI3. Benefiting from such an effective doping strategy, the as prepared Ni2+ doped CsPbI3 perovskite nanocrystals can function well as efficient red light emitter toward the fabrication of high performance perovskite LED with a peak external quantum efficiency of ~7%
author_names: Menglong Liu

Naizhong Jiang

Hai Huang

Jidong Lin

Feng Huang

Yongping Zheng

Daqin Chen
title: Ni2+ doped CsPbI3 perovskite nanocrystals with near unity photoluminescence quantum yield and superior structure stability for red light emitting devices
year: 2020

abstract: Cesium lead halide perovskite nanocrystals (NCs) have emerged as promising luminescent materials for a range of applications. However, the creation of highly luminescent violet emitting CsPbCl3 NCs mostly relies on doping of a limited number of small sized metal ions or post synthetic surface treatment of NCs. Alkaline earth (AE) metals (e.g. Ca2+ Sr2+ and Ba2+ have been proposed to be able to substitute Pb2+ in halide perovskites, yet it remains incompletely understood whether AE metal ions can be incorporated into the perovskite lattice or can be merely situated at the surface. Here, we explore the possibility of using AE metal ions for the suppression of the formation of trap centers, which leads us to develop a one pot synthetic passivation strategy to boost the violet emitting efficiency of CsPbCl3 NCs through the creation of a Ca2+/Sr2+ involved passivation layer. The photoluminescence quantum yield of violet emission reaches 77.1% by incorporating an optimal amount of Ca2+ A wide range of opti.
author_names: Jia-Kai Chen

Ju-Ping Ma

Shaoqiang Guo

Ya-Meng Chen

Qing Zhao

Bin-Bin Zhang

Zhi-Yong Li

Yang Zhou

Jingshan Hou

Yoshihiro Kuroiwa

Chikako Moriyoshi

Osman M Bakr

Junying Zhang

Hongtao Sun
title: High Efficiency Violet Emitting All Inorganic Perovskite Nanocrystals Enabled by Alkaline Earth Metal Passivation
venue: Chemistry of Materials
year: 2019

abstract: Abstract Doping metal ions into lead halide perovskite nanocrystals (NCs) has attracted great attention over the past few years due to the emergence of novel properties relevant to optoelectronic applications. Here, the synthesis of Mn2+/Yb3+ codoped CsPbCl3 NCs through a hot injection technique is reported. The resulting NCs show a unique triple wavelength emission covering ultraviolet/blue, visible, and near infrared regions. By optimizing the dopant concentrations, the total photoluminescence quantum yield (PL QY) of the codoped NCs can reach 125.3% due to quantum cutting effects. Mechanism studies reveal the efficient energy transfer processes from host NCs to Mn2+ and Yb3+ dopant ions, as well as a possible inter dopant energy transfer from Mn2+ to Yb3+ ion centers. Owing to the high PL QYs and minimal reabsorption loss, the codoped perovskite NCs are demonstrated to be used as efficient emitters in luminescent solar concentrators, with greatly enhanced external optical efficiency compared to that of using solely Mn2+ doped CsPbCl3 NCs. This study presents a new model system for enriching doping chemistry studies and future applications of perovskite NCs.
author_names: Tong Cai

Junyu Wang

Wenhao Li

Katie Hills-Kimball

Hanjun Yang

Yasutaka Nagaoka

Yucheng Yuan

Rashid Zia

Ou Chen
title: Mn2+/Yb3+ Codoped CsPbCl3 Perovskite Nanocrystals with Triple Wavelength Emission for Luminescent Solar Concentrators
venue: Advanced science
year: 2020