Red-emitting phosphors as light converters for plant-growth applications [Elektronische Ressource] = Rot emittierende Leuchtstoffe für die Anwendungen als Lichtkonverter bei der Photosynthese von Pflanzen / vorgelegt von Qi Xia

De
Red-Emitting Phosphors as Light Converters for Plant-Growth Applications Rot emittierende Leuchtstoffe für die Anwendungen als Lichtkonverter bei der Photosynthese von Pflanzen ………………………………………………………………………………………………. Der Technischen Fakultät der Universität Erlangen-Nürnberg zur Erlangung des Grades D O K T O R - I N G E N I E U R vorgelegt von Qi Xia ……………………………………………………………………………………………… Erlangen - 2011 Als Dissertation genehmigt von der Technischen Fakultät der Universität Erlangen-Nürnberg Tag der Einreichung: 24. 11. 2010 Tag der Promotion: 02. 02. 2011 Dekan: Prof. Dr.-Ing. habil. Reinhald German Berichterstatter: Prof. i.R. Dr. rer. nat. Albrecht W innackerProf. Dr.-Ing. Lothar Wondraczek Prof. Dr. Donat-Peter Häder TableofContentsChapter 1 Introduction ............................................................................... 1 References ............................................................................................. 4 Chapter 2 Theoretical basics of photoluminesctenteri amlas and photosynthetic activities of green plants .................................................................................................................................. .5.. ..................2.1 Basics of photoluminescent materials. ..................................................... 5 2+ 2+2.1.1. Eu and Mn as dopant ions ................................................. .6. ..............
Publié le : samedi 1 janvier 2011
Lecture(s) : 62
Source : D-NB.INFO/1011709554/34
Nombre de pages : 152
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Red-Emitting Phosphors as Light
Converters for Plant-Growth Applications
Rot emittierende Leuchtstoffe für die
Anwendungen als Lichtkonverter bei der
Photosynthese von Pflanzen
……………………………………………………………………………………………….

Der Technischen Fakultät der
Universität Erlangen-Nürnberg
zur Erlangung des Grades

D O K T O R - I N G E N I E U R

vorgelegt von
Qi Xia
………………………………………………………………………………………………
Erlangen - 2011







Als Dissertation genehmigt von
der Technischen Fakultät der
Universität Erlangen-Nürnberg
Tag der Einreichung: 24. 11. 2010
Tag der Promotion: 02. 02. 2011
Dekan: Prof. Dr.-Ing. habil. Reinhald German
Berichterstatter:
Prof. i.R. Dr. rer. nat. Albrecht W innacker
Prof. Dr.-Ing. Lothar Wondraczek
Prof. Dr. Donat-Peter Häder

TableofContents
Chapter 1 Introduction ............................................................................... 1
References ............................................................................................. 4
Chapter 2 Theoretical basics of photoluminesctenteri amlas and photosynthetic activities of green
plants .................................................................................................................................. .5.. ..................
2.1 Basics of photoluminescent materials. ..................................................... 5
2+ 2+
2.1.1. Eu and Mn as dopant ions ................................................. .6. ..............
2.1.2. Alkaline earth sulfides, strontium asl uamnidn aatlke aline earth silicates as host lattices 10
2.2 Basics of photosynthetic activitiesa ntofs g.r.e.en. p.l....................................... .1.4
2.2.1 General remarks .......................................................................... 14
2.2.2 Influence of light quality (wavelengthso)t osn ypnthesis .......................... .1.6. ........
2.2.3 Influence of light quantity (intensiottyo)s yonnt phhesis ............................................ .1.9. .....
2.2.4 Artificial light sources for plant td ev.e.l.o.p.m.en...................................... .21. ...
References ........................................................................................... 24
2+
Chapter 3 Investigation of tunable r ede miEsusion in alkali earth sulfides phosphorsei r and th
application as light converters ................................................................... 27
Abstract .................................................................... ...................... 27
3.1 Introduction .................................................................................. 27
3.2 Methods of materials syntheses and charatctioenrsi .za...................................................... .29.. ....
3.2.1 Materials synthesis with standard sroelaicdt sitona .t..e.............................. .2.9. .....
3.2.2 Photoluminescent, microscopic, crystalliocg rapahnd temperature-dependent
luminescence characterizations of thSe CrSa:Epuhosphors.............................. .2.9. .........1-x x
3.3 Results and discussions .................................................................... 30
3.3.1 Morphological comparison of the syntheuslifzied e sphosphor particles separated by
sedimentation process ....................................................................... 30
3.3.2 Crystallographic structures of synltfihdees ipzhedo sspuhors ................................... 3.1. ........
2+
3.3.3 Investigation of emission/excitation osfp tecther aC aSrS:Euphosphors ..................... 33 1-x x
2+
3.3.4 Thermal stability of t emhies sEuion in Ca SrS hosts ............................. .3.9. ...........1-x x
I
3.3.5 Spectral modification of a green-phloitghont-r icohnd ition by the prepared sulfide
phosphors ...................................................................................................................................... 41
2+
3.3.6 Investigations of thaned Eeuxcitonic luminescence of the sulfides phos phunodrer
synchrotron radiation ....................................................................... 44
3.4 Conclusions .................................................................................... 49
References ......................................................................................................................................... 50
2+
Chapter 4 Investigation of green and red eEmuissions in SrAOl/SrAlO prepared with oven-2 4 3 2 6
sintering and microwave-heating methods ...................................................... 51
Abstract .................................................................... ...................... 51
4.1. Introduction ................................................................................. 51
4.2 Methods of materials syntheses and charatctioenrsi .za..................................... .5.3. ....
4.2.1 Preparation of the starting materiadl-ss ftoart seo lreactions ....................... .5.3. ......
4.2.2 Synthesis with the conventional oven-gs minettehroind ........................................ 5..3. .........
4.2.3 Synthesis with the microwave-heatin.g. m.e.t..h.o.d............................... .5..3. ........
4.2.4 Photoluminescent, microscopic and crystapahlliocg rcharacterizations of the prepared
strontium aluminatphesosphors ................................................. .5..6. ................
4.3 Results and discussions ............................................................................................................... 57
4.3.1 Investigation of the temperature-tibmaes ecdu rovn est he two synthesis setups ............ 57
4.3.2 Microscopic morphological comparison ofa mtplhese synthesized by the oven-sintering
and the microwave-heating method ...................................................... .5.8
4.3.3 Investigation of crystallographic opfr otpehrte iseasm ples synthesized by oven-sintering
and microwave-heating method ........................................................... 60
2+
4.3.4 Investigation of photoluminescence of t hde opEeud SrAOl /SrAlO phosphors 2 4 3 2 6
prepared with oven-sintering and microwave-heamtetinhg ods .......................... .6.2. ..............
2+ 2+
4.3.5 About the coordination environments oifo nsS arnd the proposed hypothesis of t he Eu
substitutions in tAlhOe S/SrrAOl host lattices ............................................... 67 3 2 6 2 4
2+
4.3.6 Investigation of t hae ndE uexcitonic luminescence in the SOrA/lSrAlO phosphors 2 4 3 2 6
under synchrotron radiation at low tempera.t..u.r.e ...................................... .7.0. .....
4.4 Conclusions .................................................................................................................................. 73
References ........................................................................................... 74
2+ 2+
Chapter 5 Investigation of the two-/thrseei-obna nidn eEmuis/Mn doped alkaline earth silicates
prepared via conventional solid-state procesosl -agndel -sassisted process ..................... 7.6.. ...
II
Abstract .................................................................... ...................... 76
5.1 Introduction ................................................................................. 76
5.2 Methods of materials syntheses and chartacitonesr i.z.a.................................... .7.8 .....
2+ 2+
5.2.1 Synthesis of t/hMne Eu doped silicate phosphors with conventionatl astoel ipdr-oscess
.............................................................................................................................7..8. .......................
2+ 2+
5.2.2 Synthesis of t/hMen Eu doped silicate phosphors with sol-gel-acsessis .t..ed. .p.r.o.... 78
5.2.3 Photoluminescent, microscopic and crysatphalilco grcharacterization of the prepared
silicatpheosphors ......................................................................... 81
5.3 Results and discussions ............................................................................................................... 82
5.3.1 Investigation of the crystallograprhesic, pshtotruoc-t/ucathode-luminescence of
2+ 2+
MgSiO :Eu , Mn phosphors ........................................... ...................... 823 x mol% y mol%
5.3.2 Investigation of the crystallographreisc, pshtortucot-/ucathode-luminescence of
2+ 2+
Ca MgSi O :Eu , Mn phosphors ................................................................................. 86 2 2 7 x mol% y mol%
5.3.3 Investigation of the crystallograprhesic, pshtotruoc-t/ucathode-luminescence of
2+ 2+
CaMgSi O :Eu , Mn phosphors ........................................................... 94 2 6 x mol% y mol%
5.4 Conclusions .................................................................................... 98
References ......................................................................................................................................... 99
2+
Chapter 6 Theoretical calculations of modrif isepde cstolra by CSa rS:Eu as light converter 0.8 0.2 0.3 mol%
and photosynthetic enhancement based on model stesu d..i..................................... 1.0.2. ......
6.1 Configurations of the models ............................................................ 102
6.2 Presumptions for the model studies ......................................................................................... 103
6.3 Parameters and variables for the spectrlalt ciaolnsc u.................................... .1.0.4. ...
6.3.1 Parameters and variables for the phospahtoerd- creolmponents ................... 1.0.4. .............
6.3.2 Parameter and variable for the photosy natchtetivie cmedium ......................... 1.0.5.. ...........
6.3.3 Pre-determined spectra as input funct itonhs e ftorheoretical calculations ... .10.6.. ..............
6.4 The calculations of the modified spectorta oasndyn tphetic photon absorptions based on the
models ............................................................................................ 108
6.4.1 Spectral modifications and photosynttohne tabisco rpphtoions based on Model 1 ......... 108
6.4.2 Spectral modifications and photosynthoent aibcso prphtoions based on Model 2 ......... 113
6.5 Conclusions ................................................................................. 120
III
Chapter 7 Investigation of enhanced photosynatchtetivict y of intact spinach leaves with spectral
2+
modification by CaSrS :aEsu light converter .............................................................. .1.2.2 ....................
Abstract ........................................................................................ 122
7.1 Introduction ................................................................................ 122
7.2 Materials and methods ............................................................................................................. 124
7.2.1 Measurement of the absorption spectra ofo sypnhtohtetic pigments extracted from
spinach chloroplasts ...................................................................... 124
7.2.2 Preparation of the light converter panadr tihcel ecs onversion/reflection foils ...1.2.4. ........
7.2.3 Experimental setup of the reaction cheel lp hfoort otsynthetic activity measurements .. 124
7.2.4 Experiment procedure for the determinat iCoOn o afssimilation under modified/reference 2
light conditions ............................................................................ 126
7.3 Results and discussions .................................................................. 126
7.3.1 Spectral comparison of the modified eafnedr entceh lei grht conditions ......... .1.2.6. ............
7.3.2 Investigation of th ae sCsOimilation by intact spinach leaves underd itfihede /mroeference 2
light conditions ............................................................................ 129
7.4 Conclusions .................................................................................. 132
References ....................................................................................................................................... 132
Chapter 8 Conclusions and outlooks ............................................................ 134
8.1 Conclusions .................................................................................. 134
8.1.1 Creation of red emissions from various amlast seryistems ................................. .1.3.4. ..........
8.1.2 Innovation of synthetic methods for ph porsepharoartsions ..................... .1.3.5.. ...........
2+
8.1.3 Reveal of the origins of r edem iEsusion in SArlO host lattice ............. .1.3.5. ....................3 2 6
8.1.4 Confirmation of spectral conversions by yntthhees iszed phosphors and enhanced
photosynthetic activities ............................................................................................................. 135
8.2 Outlooks .................................................................................... 136
8.2.1 Development of phosphors with high exc itnaetnsitony in green and lower absorption in
blue ............................................................................................ 136
8.2.2 Investigations on other silicate hoslts smyasteermisa ............................... 1.3.6.. .....
8.2.3 Further optimizations of experimental eprasr afmoert the sol-gel route ....... .1.3.7 ...............
8.2.4 Further modifications of the experimuenpt faol rs ethe microwave-heating method .... 137
IV
8.2.5 Further photosynthetic experiments bahsee d tohn eotretically proposed growth-box
configurations .............................................................................................................................. 137
8.2.6 O evolution/biomass production as evaluation oirnd ifcoart photosynthetic activities .. 137 2
8.2.7 Preparations and applications of LuCoLE Dsp lfaontr developments ............... .1.3.7. ............
Zusammenfassung für die Dissertation „Rot emitndte iLeeurce htstoffe für die Anwendungen als
Lichtkonverter bei der Photosynthese von Pflan.ze.n“. .................................................................. .1.3.9.
1. Zusammenfassung ............................................................................ 139
1.1 Erzeugung von Rot-Emissionen aus Systemen vherisecdener Materialien ................. ......... 139
1.2 Innovation der Synthesemethoden für die Herlsutnge lder Leuchtstoffe ...........1.4.0. ..............
2+
1.3 Interpretation der Ursprünge der rote-n Emuission in SAlrO Wirtsgittern .................. 140 3 2 6
1.4 Bestätigung der spektralen Konversion durc hsy ndtiehetisierten Leuchtstoffe und erhöhten
photosynthetischen Aktivität ........................................................ 141
2. Ausblicke ...................................................................................................................................... 141
2.1 Entwicklung von Leuchtstoffen mit hoher Agnsriegntunensität in Grün und geringerer
Absorption in Blau .......................................................................... 141
2.2 Untersuchungen an anderen Silikat Materialien iWrtssystemen .................... .1.4.2 ...............
2.3 Weitere Optimierungen der experimentellen Param eter für die Sol-Gel-Methode ............ 142
2.4 Weitere Modifikationen des Versuchsaufbaus fdüire Mikrowellen-Erhitzungsmethode ... 142
2.5 Weitere Versuche zur Photosynthese basierendf aduen vorgeschlagenen theoretischen
Wachstumsbox-Konfigurationen .......................................................... .1.42
2.6 O-Entwicklung/Produktion von Biomasse als Indikaftüro r die Bewertung der 2
photosynthetischen Aktivitäten ....................................................... 143
2.7 Präparationen und Anwendungen von LuCoLEDs zur Pflanzen-Entwicklung ....................... 143
Acknowledgements ............................................................................................................................. 144
Curriculum Vitae .................................................................................... 145




V
Chapter1Introduction
The human history is as well a history ofo ptmehnte doevfe lthe agriculture. The efforts to
increase the crop availability and productei vnievtery bheena vstopped. The efficiency of
agriculture has been continuously enhanced thrmoeutghho ds by joint efforts from multiple
disciplines. Solutions, through traditiohneasl, aprpe rporaocvided by the technological
development of fertilizer, proper watering, atgruirceu l greenhouse for easy
CO /temperature controlling, anti-pest chemicoanlasl, crlaotsei planting, etc (Taiz and 2
Zeiger, 2006).
Light is the dominant influencing factor foopr ptrohde uctr ion: solar irradiation serves as
the ultimate energy source for photosynthetiticie s acotf ivhigher plants; when the
availability of solar energy is limited dueg et oof cwheaatn her, seasons or location reasons,
various artificial light sources could beo acpopmlpiedns ate the energy need for
photosynthesis. Incandescent lamps, halogen lafmlpuso,r escence lamps (Andersen 1986;
Bukhov et al., 1992; Ernstsen et al., 199en9t)ly alnidg hretc emitting diodes (LEDs) (Goins et
al., 1997; Tamulaitis et al., 2005; Heo e6t) aals. , g2e0ne0ral lighting facilities have all been
tested and utilized for plant growth pracevteri ctesh. e Heonewrgy utilization efficiencies
vary among the types of lamps due to differentr icelietcy-irradiation conversion
mechanisms.
It is important to consider the fact tnthast h agvree ens eplelcative utilization of light for
their photosynthetic activities. aC halndo rbo pahsy ltl he most important photosynthetic
pigments have major absorption peaks in the bldu e raedn spectral regions. In the red
spectral region the absorption peaks of chslo rloopchatylel at about 640 nm and 660 nm,
each with a broad band-width of about 60 nm 1(9H9äd9er),. Green photons are less active
for photosynthetic reactions and are transdm itretfledc taend by the leaves (Taiz and
Zeiger, 2006).
An ideal artificial light source for planhto uglrdo wbet ohne swhich could promote high
photosynthetic activities with the miintimya l ceolnescutmpritcion and maintenance cost.
First of all, the light source shouldi nb et efhfei cioenvter ting electricity into irradiation.
1
Secondly, its emission spectrum should be tumnaedt ctho photonic need of the green plants
by lowering the energetic waste in the spectiroansl wrehgich are less active for
photosynthetic activities.
With the increasing applications in general gl iagphptlicnations thanks to their energy
efficiency, LEDs serve as one of the best solu tfoiro nsthe future plant-growth applications.
Besides the assembled arrays of blue and red LEDass ebd on various III-V semiconductor
systems (Tamulaitis et al., 2005), an innogvhat isvoe ulrice could be developed by coating an
underlying LED chip with suitable phosphorst asc olnviegrhters to provide photons for the
photosynthetic needs. It is known that t hche ibpluse wLEiDth emission peaks at about 460
nm are nowadays widely available with high emi sisnitonensity, long life time and low
fabrication cost (Pimputkar et al., 2009 )is. tThhe etrefaosrke to develop suitable phosphors
with proper photoluminescent properties forl itcahte iaopnp in the plant-growth LEDs.
Besides the applications as luminescence converitn eLrE Ds, such phosphors could also be
used as sun light converters to modify thece tsorluamr tspo match the absorption spectra of
chlorophylls. As a matter of fact, green phicoht oansr e wihnactive for photosynthetic
activities account for about 35 % of thgye sion ltarh ee nervisible range (Xia, 2009). With
suitable phosphor particles imbedded in agri cfuoltilsu reor glass ceilings of the green
houses, more available photosynthetic actives pchooutldo nbe produced by solar spectrum
modification.
The following criteria need to be fulfilled tbya rtgehte phosphors as light converters for LEDs
and solar irradiation. Firstly, they shcoiuenltd lybe eexfcfitable by the readily available light
sources, i.e., the commercial blue LED chips mwiitthi nge peaks at 460 nm and green
photons (500 - 600 nm) from the solar irSraecdoinadtlyi,o nt. he emission spectra of the
phosphors should match the absorption spelcotrorpah oyfla l/c bh with two peaks at 640 nm
and 660 nm in the red range.
In this work, novel red-emitting phosphorse ewxciittha blUV-VIS light sources have been
prepared via various synthesis routes. The em iosfs itonhe dopant ions such as divalent
2+
europium ions (Eu) were studied in three different host lsautltfiidceses, aolfu minates and
2+
(when co-doped with M)n silicates. Three synthetic methods, invovelnvtinigo ncalo noven-
2
sintering, microwave-heating and sol-gel-assinsteredin gs methods, were utilized for the
material preparations. The products were inveeds tbyi gvaatrious characterization methods
to determine their photoluminescent propertsites,a lclroygraphic structures, particle micro-
morphologies, temperature stabilities, etc.n tBahsed moeasurement results, the influence
of lattice compositions, doping levels, syntarhaemseits erps, etc., on photoluminescent
properties have been analyzed. The optimized emisosn i behaviors have been achieved
through modifications of the material compino sithieo nsh ost lattices and doping
concentrations, as well as optimization of htethiec s ypnatrameters. Last but not the least,
the photosynthetic activities, indicataetd iboyn aosfs iCm Oibly intact spinach leaves, has 2
been studied under a simulated sun light condaitnd iotn he conditions modified by the
synthesized phosphors. The photosynthetic extpesr ibmaensed on the intact spinach leaves
in a reliable reaction cell show enhanced CaOssimilation rates under phosphor-modified 2
light conditions.
The thesis is structured as follows: Chaopdtuceres 2 tihnte rtheoretical background of
2+photoluminescent materials in terms of physimciss ioofn eby the dopant ions ( Eaund
2+Mn ), as well as the properties of the host(s umlaftideresi,a lasl uminates, silicates); the
basics of the photosynthesis activities laonft sh igahnde r tpheir dependence on light
quality/quantity will also be discussed in ptehr.is Chchapater 3 to 5 present the
preparations, characterizations and discusstiohnse ionvfe stigated phosphors, which are
europium doped alkali earth sulfides, europium dd opste rontium aluminates and
europium/manganese doped alkaline earth silicatreses, pectively. In Chapter 6 and 7, the
application of the synthetized calcium stlrfoindte iupmh osuphors as light converters for
photosynthetic activities will be invest igtathedor etbotichally and experimentally. In
2+Chapter 6 the modified solar spectra dbyo pEedu sulfide phosphor and photosynthetic
enhancement are theoretically calculated based evoern als growth-box configurations.
Chapter 7 discusses the photosynthetic expbyer imoentitso ring the C Oassimilation 2
rates of intact spinach leaves under the un maondi fmioedified light conditions. In Chapter
8 the key conclusions of the dissertation arrie zesdu; mamna outlook is given by introducing
the further necessary investigations and opotnsi mriezlatied to materials systems, material
synthetic techniques and photosynthetic exp.e riments
3

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