Award Abstract # 1911311
Collaborative Research: Designing New Phosphors using Computational and Experimental Co-discovery

NSF Org: DMR
Division Of Materials Research
Recipient: UNIVERSITY OF HOUSTON SYSTEM
Initial Amendment Date: May 22, 2019
Latest Amendment Date: June 7, 2022
Award Number: 1911311
Award Instrument: Continuing Grant
Program Manager: Jonathan Madison
jmadison@nsf.gov
 (703)292-2937
DMR
 Division Of Materials Research
MPS
 Directorate for Mathematical and Physical Sciences
Start Date: June 1, 2019
End Date: December 31, 2024 (Estimated)
Total Intended Award Amount: $213,332.00
Total Awarded Amount to Date: $213,332.00
Funds Obligated to Date: FY 2019 = $106,666.00
FY 2021 = $53,333.00

FY 2022 = $53,333.00
History of Investigator:
  • Jakoah Brgoch (Principal Investigator)
    jbrgoch@uh.edu
Recipient Sponsored Research Office: University of Houston
4300 MARTIN LUTHER KING BLVD
HOUSTON
TX  US  77204-3067
(713)743-5773
Sponsor Congressional District: 18
Primary Place of Performance: University of Houston
3585 Cullen Blvd., Room 112
Houston
TX  US  77204-5003
Primary Place of Performance
Congressional District:
18
Unique Entity Identifier (UEI): QKWEF8XLMTT3
Parent UEI:
NSF Program(s): CERAMICS
Primary Program Source: 01001920DB NSF RESEARCH & RELATED ACTIVIT
01002122DB NSF RESEARCH & RELATED ACTIVIT

01002223DB NSF RESEARCH & RELATED ACTIVIT
Program Reference Code(s): 054Z, 7237, 8396, 8611, 8614
Program Element Code(s): 177400
Award Agency Code: 4900
Fund Agency Code: 4900
Assistance Listing Number(s): 47.049

ABSTRACT

NON-TECHNICAL DESCRIPTION: Lighting home and commercial buildings in the US account for 6% of the total US electrical energy use and 15% of the total electrical energy expenditure, which translates to $50 billion per year. There is an outstanding opportunity to reduce this cost by replacing current incandescent and fluorescent lighting with white light emitting diodes (LEDs). However, the color quality and efficiency must be improved further. These LED-based light bulbs produce white light by using a luminescent powder called a phosphor, coating on top of a near-ultraviolet (UV) or blue-emitting LED chip. The phosphor is a key component in these devices because it is critical for the overall efficiency and color of these bulbs; unfortunately, there are only a few viable phosphors available for this application today. Therefore, it is prudent to discover new phosphor systems to fully realize the conversion to new efficient lighting. The researchers are addressing this challenge by developing computational and data-driven methods to predict the properties of phosphors. This approach allows the directed discovery of new phosphors with enhanced optical response. This grant also supports extensive scientific education including sponsoring numerous research opportunities for high school and undergraduate students. These students, mostly from underrepresented groups, are learning how to synthesize and characterize phosphors as well as the importance of this energy-efficient technology. The graduate students supported by this work are trained to pursue opportunities in the optoelectronics industry and also across the technology sector where materials science play a crucial role. Finally, the computational products of this research are disseminated through open-source platforms, so all researchers benefit from the scientific developments.

TECHNICAL DETAILS: Replacing a traditional light bulb with an energy-efficient, phosphor converted-light emitting diode is one of the easiest ways to decrease electricity consumption. This goal requires the discovery of new phosphor systems, which convert the nearly monochromatic LED light into a broad spectrum white light, to fully make use of this technology. The phosphors investigated in this project are based on wide band gap materials (hosts) that contain a small amount of activator (rare-earth element). Depending on the host:activator combination, colors across the visible spectrum are obtained. The central hypothesis driving this research is that the quantum efficiency and thermal quenching resistance of a phosphor are related to the local coordination environment of the activator ion. This research employs advanced first-principles calculations, local structure analysis using X-ray and neutron scattering, and data science to establish a quantitative understanding of this relationship. Modeling these properties using computational tools and confirming the predictions through materials synthesis and characterization produces a feedback loop where our research results are improved with each discovery. The outcome is a series of design rules that will lead to the discovery of new phosphors with superior optical properties.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH

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(Showing: 1 - 10 of 20)
Amachraa, Mahdi and Wang, Zhenbin and Chen, Chi and Hariyani, Shruti and Tang, Hanmei and Brgoch, Jakoah and Ong, Shyue Ping "Predicting Thermal Quenching in Inorganic Phosphors" Chemistry of Materials , v.32 , 2020 https://doi.org/10.1021/acs.chemmater.0c02231 Citation Details
Gray, Matthew B. and Hariyani, Shruti and Strom, T. Amanda and Majher, Jackson D. and Brgoch, Jakoah and Woodward, Patrick M. "High-efficiency blue photoluminescence in the Cs 2 NaInCl 6 :Sb 3+ double perovskite phosphor" Journal of Materials Chemistry C , v.8 , 2020 https://doi.org/10.1039/D0TC01037E Citation Details
Hariyani, Shruti and Amachraa, Mahdi and Khan, Mariam and Ong, Shyue Ping and Brgoch, Jakoah "Local environment rigidity and the evolution of optical properties in the green-emitting phosphor Ba 1x Sr x ScO 2 F:Eu 2+" Journal of Materials Chemistry C , v.10 , 2022 https://doi.org/10.1039/D1TC05411B Citation Details
Hariyani, Shruti and Armijo, Edward and Brgoch, Jakoah "Broad Green Emission in the Leucite-Like Cs 2 ZnSi 5 O 12 :Eu 2+ Phosphor" ECS Journal of Solid State Science and Technology , v.9 , 2019 10.1149/2.0222001JSS Citation Details
Hariyani, Shruti and Brgoch, Jakoah "Advancing Human-Centric LED Lighting Using Na2MgPO4F:Eu2+" ACS Applied Materials & Interfaces , 2021 https://doi.org/10.1021/acsami.1c00909 Citation Details
Hariyani, Shruti and Brgoch, Jakoah "Local Structure Distortion Induced Broad Band Emission in the All-Inorganic BaScO 2 F:Eu 2+ Perovskite" Chemistry of Materials , v.32 , 2020 https://doi.org/10.1021/acs.chemmater.0c02062 Citation Details
Hariyani, Shruti and Brgoch, Jakoah "Spectral Design of Phosphor-Converted LED Lighting Guided by Color Theory" Inorganic Chemistry , v.61 , 2022 https://doi.org/10.1021/acs.inorgchem.1c02975 Citation Details
Hariyani, Shruti and Brgoch, Jakoah and Garcia-Santamaria, Florencio and Sista, Srinivas P. and Murphy, James E. and Setlur, Anant A. "From lab to lamp: Understanding downconverter degradation in LED packages" Journal of Applied Physics , v.132 , 2022 https://doi.org/10.1063/5.0122735 Citation Details
Hariyani, Shruti and Duke, Anna C. and Krauskopf, Thorben and Zeier, Wolfgang G. and Brgoch, Jakoah "The effect of rare-earth substitution on the Debye temperature of inorganic phosphors" Applied Physics Letters , v.116 , 2020 https://doi.org/10.1063/1.5142167 Citation Details
Hariyani, Shruti and Sójka, Magorzata and Setlur, Anant and Brgoch, Jakoah "A guide to comprehensive phosphor discovery for solid-state lighting" Nature Reviews Materials , v.8 , 2023 https://doi.org/10.1038/s41578-023-00605-6 Citation Details
Hariyani, Shruti and Xing, Xinxin and Amachraa, Mahdi and Bao, Jiming and Ong, Shyue Ping and Brgoch, Jakoah "Realizing WideGamut HumanCentric Display Lighting with K 3 AlP 3 O 9 N:Eu 2+" Advanced Optical Materials , v.11 , 2023 https://doi.org/10.1002/adom.202202689 Citation Details
(Showing: 1 - 10 of 20)

PROJECT OUTCOMES REPORT

Disclaimer

This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.

Rare-earth substituted inorganic phosphors play a crucial role in solid-state lighting and display technologies, where they enable high-efficiency white light generation and color rendering. However, developing new phosphors with high quantum efficiency (QE), strong resistance to thermal quenching (TQR), and tailored optical properties remains a significant challenge. This multi-year research project aimed to address these challenges by integrating experimental synthesis and characterization with computational modeling and ab initio molecular dynamics (AIMD) simulations. Conducted at the University of Houston and the University of California, San Diego (UCSD), the project led to the discovery and characterization of novel phosphors, advancing fundamental understanding and accelerating materials discovery for next-generation lighting applications. The project resulted in 20 research products and trained multiple students, including graduate students, undergraduate students, and postdoctoral scholars.

This project deepened the understanding of phosphor chemistry by developing a predictive model for thermal quenching that incorporates both crossover and thermal ionization mechanisms, demonstrating sigificant intellectual merit. Ab inition molecular dynamic (AIMD) simulations were used to reveal that the stability of an activator’s local environment is a crucial factor influencing thermal quenching behavior. The model successfully predicted thermal quenching values for 29 known phosphors with a root-mean-square error of ~5%, demonstrating its accuracy in identifying thermally stable phosphors. This computational framework then facilitated the efficient screening of new phosphor candidates, leading to several promising discoveries.

Experimentally, the research focused on synthesizing phosphors emitting in the green, cyan, and blue spectral regions, which are essential for full-spectrum white light applications. Several novel phosphors were reported, including Cs2ZnSi5O12:Eu2+, NaMgBO3:Ce3+, Ba5Si8O21:Ce3+, and Cs2NaInCl6:Sb3+, each optimized for lighting technologies. Na2MgPO4F:Eu2+ emerged as an exceptionally stable phosphor, enabling the development of a prototype LED with superior chromatic stability. The discovery of (Na,K)3AlP3O9N:Eu2+, with its ultra-narrow blue emission, has significant implications for high-resolution display technologies. Two patents have been filed based on these breakthroughs.

Another significant outcome of the research was the identification of local structural distortions as key factors influencing phosphor optical properties. In the BaScO2F perovskite system, Eu2+ substitution induced structural distortions that led to multiple emission peaks, emphasizing the need for local coordination analysis in phosphor design. Additionally, h-BAS:Eu powders were studied using photoluminescence, cathodoluminescence, electron paramagnetic resonance, and density functional theory calculations to understand the impact of barium vacancies on optical performance. These findings highlight the role of defects and distortions in tuning phosphor emissions, providing future pathways for engineering new materials.

The final phase of the project focused on phosphors with narrow emission bandwidths, a critical requirement for high-efficiency LED and display applications. The solid-solution phosphor series MI2.97Eu0.015MIIIP3O9N (MI = Na, K; MIII = Al, Ga, In) was systematically studied to determine how cation substitution affects emission properties. This work provides fundamental insights into the relationship between host structure chemistry and photoluminescence behavior, guiding future phosphor development.

This project also made a significant contribution to education and workforce development. Two PhD-level graduate students gained expertise in materials synthesis, optical characterization, and computational analysis. One also engaged in an international collaboration by visiting the University of Augsburg to learn new synthesis techniques of air sensitive materials, which were later applied in this project upon her return to the University of Houston.

Multiple undergraduate students were actively involved, receiving hands-on training in materials synthesis and characterization. Each student contributed to research on luminescent materials, learning how to make new materials, characterize their properties, and understand the process of phosphor discovery. These experiences have provided them with valuable skills applicable to future academic and professional careers.

Beyond student training, this research has supported broader STEM education efforts through outreach initiatives. The ENLACE summer research program at UCSD, one of the largest in the United States, worked with 89 high school students and 96 undergraduates in hands-on STEM experiences.

Additionally, computational models developed in this project have been applied to large-scale crystal structure databases, such as ICSD and the Materials Project, to identify potential phosphor hosts with high QE and low TQR. These models continue to be refined and are publicly available, facilitating broader adoption within the materials research community.

In summary, this project made significant advancements in the field of luminescent materials by elucidating key mechanisms that govern phosphor performance, developing predictive models for thermal quenching, and discovering novel materials with applications in solid-state lighting and displays. The integration of computational and experimental approaches has proven highly effective in accelerating the discovery of phosphors. Educational and outreach initiatives have trained the next generation of scientists while fostering a broader appreciation for materials research. These contributions align with the NSF’s mission to advance scientific knowledge and generate broader societal benefits through research and education.

 


Last Modified: 03/31/2025
Modified by: Jakoah Brgoch

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