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Mn 4+ ‐related photoemission enhancement via energy transfer in La 2 MgGeO 6 :Dy 3+ , Mn 4+ phosphor for plant growth light‐emitting diodes
Author(s) -
Chen Wei,
Shen Linli,
Shen Chenyang,
Zhang Zelong,
Liang Xiaojuan,
Xiang Weidong
Publication year - 2019
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.15923
Subject(s) - phosphor , analytical chemistry (journal) , luminescence , materials science , high resolution transmission electron microscopy , light emitting diode , transmission electron microscopy , chemistry , optoelectronics , nanotechnology , chromatography
A double perovskite‐type substrate of La 2 MgGeO 6 ( LMGO ) was successfully synthesized via a high‐temperature solid‐state reaction method and was codoped with Mn 4+ and Dy 3+ to form a new deep‐red phosphor ( LMGO :Mn 4+ ,Dy 3+ ) for artificial plant growth light‐emitting diodes ( LED s). This extraordinary phosphor can exhibit strong far‐red emission with a maximum peak at 708 nm between 650 and 750 nm, which can be ascribed to the 2 E g → 2 A 2 g spin‐forbidden transition of Mn 4+ . The X‐ray diffraction ( XRD ) patterns and high‐resolution transmission electron microscopy ( HRTEM ) clarified that the La 3+ sites in the host were partly replaced by Dy 3+ ions. Moreover, we discovered energy transfers from Dy 3+ to Mn 4+ by directly observing the significant overlap of the excitation spectrum of Mn 4+ and the emission spectrum of Dy 3+ as well as the systematic relative decline and growth of the emission bands of Dy 3+ and Mn 4+ , respectively. With the increase in the activator (Mn 4+ ) concentration, the relationship between the luminescence decay time and the energy transfer efficiency of the sensitizer (Dy 3+ ) was studied in detail. Finally, an LED device was fabricated using a 460 nm blue chip, and the as‐obtained far‐red emitting LMGO :Mn 4+ ,Dy 3+ phosphors for Wedelia chinensis cultivation. As expected, the as‐fabricated plant growth LED ‐treated Wedelia chinensis cultured in the artificial climate box with overhead LED s demonstrated that after 28 days of irradiation, the average plant growth rate and the total chlorophyll content were better than those of specimens cultured using the commercial R‐B LED lamps, indicating that the as‐prepared phosphor could have a potential application in the agricultural industry.