Combinatorial Screening and Optimization of Luminescent Materials and Organic Light-Emitting Devices
- PDF / 3,618,454 Bytes
- 7 Pages / 612 x 792 pts (letter) Page_size
- 18 Downloads / 180 Views
Combinatorial
Screening and Optimization of Luminescent Materials and Organic LightEmitting Devices Ted X. Sun and G.E. Jabbour
Abstract The rapid development of modern photonic technologies—for example, mercury-free lamps, flat-panel displays, and solid-state lamps—demands the timely discovery of advanced phosphors. A combinatorial process has been developed to dramatically accelerate the experimental search for such phosphors. High-density phosphor “libraries” containing from 100 to over 1000 discrete chemical compositions on a 1 in. 1 in. substrate have been made in thin-film or powder form using selective vapor deposition and liquid-dispensing techniques, respectively. In this article, the existing methods of combinatorial synthesis and screening of phosphors will be reviewed with examples. These methods may also be used to screen organic-based solid-state materials and optimize their device properties. In this regard, combinatorial and spreading techniques have been utilized to study and rapidly optimize organic light-emitting devices (OLEDs). Keywords: combinatorial methods, luminescent materials, optical materials, optical properties, organic light-emitting devices (OLEDs).
Combinatorial Synthesis and Screening of Luminescent Materials Although the search for advanced phosphors began about a century ago,1 the recent emergence of photonic technologies—for example, mercury-free fluorescent lamps,2 various flat-panel displays,3 and computed tomography4 —demands new phosphors with advanced properties, including high quantum efficiencies (QEs), good absorption of the excitation energy, adequate color coordinates, long lifetimes, and low cost.
MRS BULLETIN/APRIL 2002
Discovering advanced phosphors with multiple superior properties remains a difficult problem. The specific spectral properties, absorption, QEs, and lumen maintenance depend on complex interactions among such aspects as the excitation source, the host composition and structure, process condition and defects, and fluorescent dopants. Luminescent properties are highly sensitive to dopant composition, host stoichiometry, and processing conditions.1 Consequently, the identification of phosphors that are ideally
suited to the requirements of a given photonic application is highly empirical. To accelerate the search for advanced phosphors for various photonic applications, a high-throughput combinatorial strategy was developed to synthesize and screen phosphors for advanced luminescent properties. This short review covers some existing effective technologies for synthesizing and screening phosphors, with examples of a few novel phosphors discovered by the combinatorial process.
Combinatorial Deposition and Synthesis of Phosphors: High-Density Thin-Film Phosphor Libraries Fabricated by Physical Vapor Deposition and Masking Thin-film deposition and a masking strategy were used to generate a thin-film “spatially addressable library,” in which each sample on the library is formed from a multiple-layered precursor.5,6 Following deposition of the precurs
Data Loading...
