Upconversion of infrared to visible light in rare-earths doped phosphate phosphors for photodynamic therapy application
| dc.contributor.advisor | Ntwaeaborwa, O. M. | en_ZA |
| dc.contributor.advisor | Swart, H. C. | en_ZA |
| dc.contributor.author | Mokoena, Puseletso Pricilla | en_ZA |
| dc.date.accessioned | 2018-01-24T09:46:09Z | |
| dc.date.available | 2018-01-24T09:46:09Z | |
| dc.date.issued | 2017 | en_ZA |
| dc.description | Thesis (Ph.D.(Physics))--University of the Free State, 2017 | en_ZA |
| dc.description.abstract | 𝑬𝒏𝒈𝒍𝒊𝒔𝒉 Phosphate phosphors have emerged as an important family of luminescent material due to their low sintering temperature, broad band gaps, high thermal and chemical stability, and moderate phonon energies. Their structure can provide a wide range of possible cationic substitutions since there are different inequivalent sites of metal ions presenting a large-scale of size and coordination spheres. Rare earth ions doped phosphate compounds as luminescence materials have been widely investigated in different host lattices including phosphates. In this study, the luminescent properties of different phosphate phosphors doped with Er3+, Eu3+, and Yb3+ were investigated. Er3+ and Yb3+ singly doped, and Er3+/Yb3+ co-doped Ba5(PO4)3OH phosphor powders were successfully synthesized by the urea combustion method. The X-ray Diffraction (XRD) patterns exhibited hexagonal structure for Ba5(PO4)3OH referenced in the ICDD (International Center for Diffraction Data) Card Number 00-024-0028. There were no peak shifts nor secondary peaks observed suggesting that pure phases were crystallized. The Scanning Electron Microscope (SEM) image showed that the particles were agglomerated together forming ellipsoidal shapes. The Energy Dispersive x-ray Spectroscopy (EDS) spectra with intense peaks of Ba, P, and O were observed confirming the formation of Ba5(PO4)3OH. The particle size distribution of the Ba5(PO4)3OH powder was estimated from a statistical analysis by measuring approximately 10 particles. The average particles length and width were 867 and 169 nm, respectively. Upon excitation using a 980 nm laser, multiple emission peaks in the green region and red region were observed corresponding to the transition of the Er3+ ion. By further co-doping with Yb3+ the red emission was enhanced due to energy transfer from Yb3+ to Er3+. Ba5(PO4)3OH co-doped with Eu3+ and Yb3+ phosphors were prepared by the urea combustion method. The diffraction peaks of Ba5(PO4)3OH were indexed to the pure hexagonal phase, referenced in ICDD Card Number 00-024-0028. The SEM images showed a change (ranging from rods, spherical, needle-like to non-uniform particles) in surface morphology which was due to annealing and addition of dopants. The size of the particles appeared to be larger/bigger when comparing as-prepared and annealed phosphor powders. This could be due to the annealing-induced expansion. The broad intense excitation peak at 240 nm and other excitation peaks located at ~319, 360, 382, 395 and 465-537 nm were assigned to transitions of Eu3+ ion. The emission peaks were observed at ~589, 614, 651 and 699 nm. Upon co-doping with Yb3+, the strong emission peak was observed at 657 nm assigned to the Eu3+ transitions. This was due to the cooperative energy transfer process. Er3+ and Yb3+ co-doped Ca5(PO4)3OH samples were synthesized by urea the combustion method. The XRD patterns of Ca5(PO4)3OH powders for both as-prepared and those annealed at 800 0C were attributed to the hexagonal phase of Ca5(PO4)3OH referenced in ICDD Card No. 00-073-0293. The SEM micrographs exhibited rod or plate-like morphology forming flowers, plate-like structures and small agglomerated particles on top of the plates. For Er3+ singly doped phosphors emission peaks were observed in the green region ranging from 517 -573 nm and red region in the range of 653- 679 nm. Ca5(PO4)3OH:Er3+ phosphors were prepared using different concentrations of Er3+ ranging from 1-7 mol.%. The photoluminescence intensity increased with increasing concentrations from 1 to 3 mol%, and decreased at high concentrations of 5 and 7 mol.% due to concentration quenching effects. Adding different concentrations (5-15 mol.%) of Yb3+. The emission intensities on both the green and red region increased with increasing concentrations of Yb3+ ions. The enhancement of green emission can be due to increasing of the three-photon energy transfer process probability between the Yb3+ and Er3+ ions. Ca5(PO4)3OH:Eu3+, Yb3+ phosphor powders were synthesized by the combustion method using urea as a fuel. The XRD patterns of Ca5(PO4)3OH powders for both as-prepared and those annealed at 800 0C were assigned to the hexagonal phase of Ca5(PO4)3OH referenced in ICDD Card No. 00-073-0293. The crystal sizes calculated for as-prepared and annealed powders were found to be 27 and 44 nm, respectively. UC emission spectrum of Ca5(PO4)3OH:Eu3+,Yb3+ phosphor powder was observed under 980 nm excitation. Prominent red emission from Eu3+ ion was clearly observed at 613 nm together with minor emission peaks at 547, 591, 654 and 697 nm. The prominent red emission from Eu3+ was due to energy transfer from Yb3+ ion. A cooperative energy transfer from Yb3+ ion pair to a single Eu3+ ion occurred by fast non-radiative relaxation to the metastable 5D0 state, and the red Eu3+ emission was observed. Sr5(PO4)3OH co-doped Er3+/Yb3+ phosphor powders were synthesized by combustion method. The XRD pattern diffraction peaks were consistent with the standard data referenced in ICDD Card No. 00-033-1348. The average crystallite size calculated was 43 ± 2 nm. The SEM micrographs showed that the powder was composed of agglomerated particles with edges forming hexagonal shapes. The agglomeration showed a porous structure resulting from the nature of the combustion reaction associated with the evolution of large volume of gases. Upon 980 nm excitation, Sr5(PO4)3OH:Er3+ exhibited multiple emission bands in the green region and a less intense peak in the red region. The strong red emission peak with two minor splits were observed at 661 nm, and (651 and 679 nm), by co-doping with Yb3+ ion. Sr5(PO4)3OH co-doped Eu3+/Yb3+ phosphor powders were synthesized by the combustion method. All the diffraction patterns matched with the standard data referenced by ICDD Card No. 00-033-1348. The SEM image showed that the powder composed of a network of particles with irregular shapes and small bright particles encrusted on the surface of the bigger particles. The particles containing heavy atoms in backscattered electron detector were stronger than light particles and they appear brighter. UC emission spectrum of Sr5(PO4)3OH:Eu3+,Yb3+ phosphor powder was observed under 980 nm excitation. Prominent red emission from Eu3+ ion was clearly observed at 658 nm due to cooperative energy transfer process. Photodynamic therapy uses special drugs, called photosensitizers, along with light to kill cancer cells. The drugs only works after been activated by certain kinds of light. Most drugs are activated by red light. The enhanced red luminescence from the above mentioned phosphors suitable to activate different photosensitizers for treatment of cancer or photodynamic therapy. Photodynamic therapy activity was performed using red emitting phosphors prepared in this study together with phthalocyanine as a photosensitizer. Phthalocyanine is activated by the wavelength ~670 nm. The activity results are discussed in chapter 10. ___________________________________________________________________ | en_ZA |
| dc.description.abstract | 𝑨𝒇𝒓𝒊𝒌𝒂𝒂𝒏𝒔 Fosfaatfosfore het na vore gekom as 'n belangrike familie van helder materiaal vanweë hul lae sintertemperatuur, breë bandgapings, hoë termiese en chemiese stabiliteit en matige fononenergieë. Die struktuur kan 'n wye reeks moontlike kationiese plaasvervangers verskaf aangesien daar verskillende ongelykwaardige plekke van metaalione is wat 'n grootskaalse grootte en koördinasie van sfere aanbied. Seldsame aardelemente dokteer fosfaatverbindings as helder material en is wyd ondersoek in verskillende gasheerroosters insluitend fosfate. In hierdie studie is die helder eienskappe van verskillende fosfaatfosfore wat met Er3+, Eu3+ en Yb3+ gedokteer is, ondersoek. Er3+ en Yb3+ enkelgedokteerde, en Er3+/Yb3+ saamgedokteerde Ba5(PO4)3OH fosforpoeiers is suksesvol gesintetiseer deur die ureum verbrandingsmetode. Die X-straaldiffraksie (XRD) patrone het seskantige struktuur getoon vir Ba5(PO4)3OH waarna verwys word in die ICDD (Internasionale Sentrum vir Diffraksie Data) Kaartnommer 00-024-0028. Daar was geen piekverskuiwings of sekondêre pieke waargeneem wat daarop dui dat suiwer fases gekristalliseer is nie. Die skandeerelektronmikroskoop (SEM) beeld het getoon dat die deeltjies saam geagglomereer is en ellipsoïdale vorms vorm. Die Energie Dispersiewe X-straalspektroskopie (EDS) spektra met intense pieke van Ba, P en O is waargeneem, wat die vorming van Ba5(PO4)3OH bevestig. Die deeltjiegrootteverspreiding van die Ba5(PO4)3OH-poeier is beraam uit 'n statistiese analise deur ongeveer 10 deeltjies te meet. Die gemiddelde deeltjies se lengte en breedte was onderskeidelik 867 en 169 nm. Met opwekking met behulp van 'n 980 nm laser, is veelvuldige emissiepieke in die groen gebied en rooi gebied waargeneem wat ooreenstem met die oorgang van die Er3+ ioon. Deur verdere mededoktering met Yb3+ is die rooi emissie verbeter as gevolg van energie-oordrag van Yb3+ na Er3+. Ba5(PO4)3OH, wat saam met Eu3+ en Yb3+-fosfore gedokteer is, is deur die ureumverbrandingsmetode berei. Die diffraksiepieke van Ba5(PO4)3OH is geïndekseer na die suiwer heksagonale fase, waarna verwys word in ICDD-kaartnommer 00-024-0028. Die SEM-beelde het 'n verandering (wat wissel van stawe, sferiese, naaldagtige tot nie-uniforme deeltjies) in oppervlakmorfologie getoon wat te wyte was aan uitgloeiing en toevoeging van dokteermiddels. Die grootte van die deeltjies blyk groter te wees wanneer as-voorbereide en uitgegloeide fosforpoeiers vergelyk word. Dit kan wees as gevolg van die uitgloeiing-geïnduseerde uitbreiding. Die breë intense opwekkingspiek by 240 nm en ander opwekkingspieke geleë by ~319, 360, 382, 395 en 465-537 nm is aan oorgange van die Eu3+ ioon toegeken. Die emissiepieke is by ~589, 614, 651 en 699 nm waargeneem. By mede-doktering met Yb3+, is die sterk emissiepiek waargeneem by 657 nm wat aan die Eu3+ oorgange toegeken is. Dit was as gevolg van die koöperatiewe energie-oordragproses. Er3+ en Yb3+ saamgedokteerde Ca5(PO4)3OH-monsters is gesintetiseer deur ureum tydens die verbrandingsmetode. Die XRD-patrone van Ca5(PO4)3OH-poeiers vir beide as-voorbereide en dié wat by 800 0C uitgegloei is, is toegeskryf aan die heksagonale fase van Ca5(PO4)3OH waarna verwys word in ICDD Kaart No. 00-073-0293. Die SEM mikrografieke het staaf- of plaatagtige morfologie getoon wat blomme, plaatagtige strukture en klein geagglomereerde deeltjies bo-op die plate vorm. Vir Er3+ is enkelgedokteerde fosfor-emissiepieke waargeneem in die groen gebied wat tussen 517 -573 nm wissel en die rooi gebied in die omgewing van 653 - 679 nm. Ca5(PO4)3OH:Er3+-fosfor is berei deur gebruik te maak van verskillende konsentrasies Er3+ wat wissel van 1-7 mol.%. Die fotohelder-intensiteit het toegeneem met toenemende konsentrasies van 1 tot 3 mol%, en het afgeneem by hoë konsentrasies van 5 en 7 mol.% as gevolg van ’n konsentrasie bluseffekte. Voeg verskillende konsentrasies (5-15 mol.%) Yb3+ by. Die emissie-intensiteite op beide die groen en rooi gebied het toegeneem met toenemende konsentrasies van Yb3+ ione. Die verbetering van groen emissie kan wees as gevolg van die verhoging van die drie-foton energieoordragproses, waarskynlikheid tussen die Yb3+ en Er3+ ione. Ca5(PO4)3OH:Eu3+, Yb3+ fosforpoeiers is gesintetiseer deur die verbrandingsmetode met ureum as brandstof. Die XRD-patrone van Ca5(PO4)3OH-poeiers vir beide as-bereide en dié wat by 800 0C uitgegloei is, is toegeken aan die seskantige fase van Ca5(PO4)3OH waarna verwys word in ICDD-kaart nr. 00-073-0293. Die kristalgroottes bereken vir as-bereide en uitgegloeide poeiers is onderskeidelik 27 en 44 nm gevind. UC-emissiespektrum van Ca5(PO4)3OH:Eu3+, Yb3+ fosforpoeier is waargeneem onder 980 nm opwekking. Prominente rooi emissie van die Eu3+ ioon is duidelik waargeneem by 613 nm saam met geringe emissiepieke by 547, 591, 654 en 697 nm. Die prominente rooi emissie van Eu3+ was as gevolg van energie-oordrag vanaf die Yb3+ ioon. 'n Koöperatiewe energie-oordrag van Yb3+ ioonpaar na 'n enkele Eu3+ ioon het plaasgevind deur vinnige nie-stralingsverslapping na die metastabiele 5D0 toestand, en die rooi Eu3+ emissie is waargeneem. Sr5(PO4)3OH saamgedokteerde Er3+/Yb3+ fosforpoeiers is gesintetiseer deur middel van die verbrandingsmetode. Die XRD patroon diffraksiepieke was in ooreenstemming met die standaard data waarna verwys word in ICDD Kaart No. 00-033-1348. Die gemiddelde kristallietgrootte wat bereken is, was 43 ± 2 nm. Die SEM mikrografieke het getoon dat die poeier saamgestel is uit geagglomereerde deeltjies met rande wat heksagonale vorms vorm. Die agglomerasie het 'n poreuse struktuur getoon wat voortspruit uit die aard van die verbrandingsreaksie wat verband hou met die evolusie van groot volume gasse. By 980 nm opwekking het Sr5(PO4)3OH:Er3+ veelvuldige emissiebande in die groen gebied vertoon en 'n minder intense piek in die rooi gebied. Die sterk rooi emissiepiek met twee geringe splitsings is waargeneem by 661 nm, en (651 en 679 nm), deur mede-doktering met die Yb3+ ioon. Sr5(PO4)3OH mede-gedokteerde Eu3+/Yb3+ fosforpoeiers is gesintetiseer deur die verbrandingsmetode. Al die diffraksiepatrone het ooreengestem met die standaarddata waarna verwys word deur ICDD-kaartnommer 00-033-1348. Die SEM-beeld het getoon dat die poeier bestaan uit 'n netwerk van deeltjies met onreëlmatige vorms en klein helder deeltjies op die oppervlak van die groter deeltjies. Die deeltjies wat swaar atome in terugverstrooide elektrondetektor bevat, was sterker as ligte deeltjies en hulle lyk helderder. Die UC-emissiespektrum van Sr5(PO4)3OH:Eu3+, Yb3+ fosforpoeier is waargeneem onder 980 nm opwekking. Prominente rooi emissie van die Eu3+ ioon is duidelik waargeneem by 658 nm as gevolg van samewerkende energie-oordragproses. Fotodinamiese terapie gebruik spesiale middels, genaamd fotosensitiseerders, saam met lig om kankerselle dood te maak. Die middels werk eers nadat dit deur sekere soorte lig geaktiveer is. Die meeste middels word deur rooi lig geaktiveer. Die verbeterde rooi luminessensie van bogenoemde fosfor wat geskik is om verskillende fotosensibiliseerders te aktiveer vir behandeling van kanker of fotodinamiese terapie. Fotodinamiese terapie-aktiwiteit is uitgevoer met behulp van rooi-emitterende fosfors wat in hierdie studie saam met ftalosianien as 'n fotosensibiliseerder voorberei is. Ftalosianien word geaktiveer deur die golflengte ~670 nm. Die aktiwiteitsresultate word in hoofstuk 10 bespreek. ___________________________________________________________________ | af_ZA |
| dc.description.abstract | 𝑺𝒆𝑺𝒐𝒕𝒉𝒐 Phosphate phosphors di hlahella e le mofuta wa bohlokwa wa thepa e kganyang ka lebaka la thempheretjha ya tsona e phahameng hanyenyane, makgalo a broad band, botsitso ba thermal e phahameng le ba dikhemikhale, esita le matla a lekaneng hantle a bohareng a phonon. Sebopeho sa tsona se ka fana ka menyetla e mengata ya phetolo tsa cationic kaha ho na le dikarolo tse ngata tse sa lekaneng tsa metal ions tse hlahisang karolo e kgolo ya boholo le ya kgokahano. Ho entswe dipatlisiso tsa metswako ya rare earth ions doped phosphate e le thepa ya luminescence ho host lattices tse fapaneng tse kenyeletsang difosfeiti. Diphuputsong tsena dikarolwana tse luminescent tse fapaneng tsa phosphate phosphors doped with Er3+, Eu3+, le Yb3+ di ile tsa batlisiswa ka botlalo. Er3+ le Yb3+ singly doped, and Er3+/Yb3+ co-doped Ba5(PO4)3OH phosphor powders di ile tsa kopanywa ka katleho ka ho sebedisa mokgwa wa urea wa ho tukisa kapa ho eketsa motjheso. Dipaterone tse fapaneng tsa X-ray Diffraction (XRD) di hlahisitse sebopeho se hexagonal bakeng sa Ba5(PO4)3OH e boletsweng ho ICDD (International Center for Diffraction Data) Card Number 00-024-0028. Ho ne ho se na diphetoho tsa bophahamo kapa sehlohlolo kapa tsona tsa sekondari tse lemohilweng tse totobatsang hore dikgato tse hlakileng di ile tsa fetolwa dikristale. Scanning Electron Microscope (SEM) image e ile ya bontsha hore dikarolwana di kopantswe hammoho ho theha dibopeho tse ellipsoidal. Energy Dispersive x-ray Spectroscopy (EDS) spectra with intense peaks of Ba, P, and O di ile tsa hlokomelwa bakeng sa ho tiisa ho thehwa ha Ba5(PO4)3OH. Kabo ya boholo ba dikarolwana ya phoshwana ya Ba5(PO4)3OH e ile ya lekanyetswa ka mokgwa wa tshekatsheko ya dipalopalo ka ho metha palo e ka bang dikarolwana tse 10. Palohare ya bolelele le bophara ba dikarolwana e ne e le 867 le 169 nm ka ho latelana. Nakong ya keketso ya matla ka ho sebedisa 980 nm laser, bophahamo ba ho hlatsa kapa ho ntshwa lebatoweng le letala le lebatowa le lefubedu ho ile ha hlokomelwa mme ho tsamaelana le phetoho ya Er3+ ion. Ka ho kopanya hape le Yb3+ ho ntshwa ho ho fubedu ho ile ha eketswa ka lebaka la phetiso ya matla ho tswa ho Yb3+ ho ya ho Er3+. Ho tswakwa ha Ba5(PO4)3OH le Eu3+ hammoho le Yb3+ phosphors ho ile ha hlophiswa ka ho sebedisa mokgwa wa urea wa keketso ya motjheso kapa ho tukisa. Tekanyo ya bolelele ba sebaka kapa diffraction peaks of Ba5(PO4)3OH e tla be e bontshwa ho kgato ya pure hexagonal, e boletsweng ho ICDD Card Number 00-024-0028. Ditshwantsho tsa SEM di hlahisa phetoho (e tlohang ka dithupa, spherical, e kang dinale ho isa ho dikarolwana tse sa tshwaneng) ho sebopeho sa sebaka se bileng ka lebaka la kekeso ya motjheso le keketso ya dopants. Boholo ba dikarolwana bo bonahetse bo phatlaletse/ bo le boholo ha bo bapiswa le bo hlophisitsweng le phoshwana tsa phosphor tse ekeditsweng motjheso. Hona ho ka bakwa ke ho saroloha ka lebaka la ho eketsa motjheso. Dikeketso tse ding tsa motjheso ka bophahamo ba ho fihla ho 240 nm esita le ho phahama ho hong ha motjheso ho fihlang ho ~319, 360, 382, 395 le 465-537 nm di lebisitswe ho diphetoho tsa Eu3+ ion. The emission peaks were observed at ~589, 614, 651 and 699 nm. Ka ho eketsa mothamo ka Yb3+, tlhahiso e phahameng e bonahetse ho 657 nm e abetsweng diphetoho tsa Eu3+. Hona e bile ka lebaka la tshebetso ya phetiso ya matla ka kopanelo. Er3+ le Yb3+ di tswakile hammoho disampole tsa Ca5(PO4)3OH di ne di kopantswe hammoho ka ho sebedisa mokgwa wa urea wa keketso ya motjheso kapa ho tuka. Dipaterone tsa XRD tsa diphoshwana tsa Ca5(PO4)3OH bakeng sa tse hlophisitsweng le tse futhumaditsweng ka 800 0C di bapisitswe le kgato ya hexagonal ya Ca5(PO4)3OH e boletsweng ho ho ICDD Card No. 00-073-0293. SEM micrographs di bontshitse sebopeho se kang sa thupa kapa poleiti mme di theha dipalesa, dibopeho tse kang poleiti le dikarolwana tse nyenyane tse kopaneng ka hodima dipoleiti. Bakeng sa Er3+ singly doped phosphors tlhahiso e phahameng e bonahetse lebatoweng le letala ho tloha ho 517 -573 nm athe lebatoweng le lefubedu ke ho tloha ho 653- 679 nm. Ca5(PO4)3OH:Er3+ phosphors di hlophisitswe ka ho sebedisa metswako e fapaneng ya Er3+ e tlohang ho 1-7 mol.%. Sekgahla sa photoluminescence se eketsehile ka ho eketseha ha metswako ho tloha ho 1 ho isa ho 3 mol.%, mme tsa fokotseha ka motswako o phahameng wa 5 le 7 mol.% ho ya ka ditlamorao tse thusang motswako. Ho eketsa metswako e fapaneng (5-15 mol.%) ya Yb3+. Sekgahla sa emission se ntse se eketseha mabatoweng a botala le bofubedu a eketsehileng ka metswako ya Yb3+ ions. Ho eketseha ha tlhahiso e tala e ka ba ka lebaka la ho eketseha ha tshebetso ya phetiso ya three-photon energy pakeng tsa Yb3+ le Er3+ ions. Diphoshwana tsa Ca5(PO4)3OH:Eu3+, Yb3+ phosphor di ne di kopantswe ka mokgwa wa ho futhumatsa kapa ho eketsa motjheso ka ho sebedisa mokgwa wa urea jwaloka petrolo. Dipaterone tsa XRD tsa diphoshwana tsa Ca5(PO4)3OH bakeng sa tse hlophisitsweng le tse tjhesisitsweng ka 800 0C di filwe kgato ya hexagonal ya Ca5(PO4)3OH e boletsweng ho ICDD Card No. 00-073-0293. Dikristale tsa boholo bo fapaneng di badilwe bakeng sa diphoshwana tse hlophisitsweng le tse futhumaditsweng di fumanwe e le 27 le 44 nm, ka ho latelana. Boholo ba UC emission spectrum ba phoshwana ya Ca5(PO4)3OH:Eu3+,Yb3+ phosphor bo bonahetse ho ya ka sekgahla sa matla sa 980 nm. Prominent red emission e tswang ho Eu3+ ion e hlokometswe ka ho hlaka ka 613 nm hammoho le minor emission peaks ka 547, 591, 654 le 697 nm. Prominent red emission ho tswa ho Eu3+ e ne e le ka lebaka la phetiso ya matla ho tswa ho Yb3+ ion. Ho hlokometswe phetiso ya matla a kopanelo ho tswa ho bobedi ba Yb3+ ion ho ya ho bonngwe ba Eu3+ ion ho etsahetse ka ho phomola ha fast non-radiative relaxation boemong ba metastable 5D0, mme ho lemohilwe red Eu3+ emission. Ka ho sebedisa keketso ya motjheso kapa ho tuka Sr5(PO4)3OH co-doped Er3+/Yb3+ phosphor powders di ile tsa kopanywa. Paterone ya XRD ya ho phahama ha diffraction ho ne ho amana le dintlha tswa tlwaelo tse boletsweng ho ICDD Card No. 00-033-1348. Palohare ya boholo ba kristale bo badilweng e ne e le 43 ± 2 nm. SEM micrographs e bontshitse hore phoshwana e ne e kopantswe le dikarolwana tse ding tse kopaneng qetellong ho etsa sebopeho sa hexagonal. Kopano kapa ho tswakana hona ho bontsha sebopeho se nang le masoba se bakwang ke mofuta wa keketso ya motjheso o amanywang le ho hlaha ha bongata ba gase. Palo e ka bang 980 nm ya Sr5(PO4)3OH:Er3+ e hlahisitse multiple emission bands lebatoweng le letala le ho fokola kapa ho theoha lebatoweng le lefubedu. Ho hlaha ho matla ha red emission peak ho nang le dikarolwana tse pedi ho bonahetse ka 661 nm, le (651 le 679 nm), ka ho kopanya le Yb3+ ion. Diphoshwana tsa Sr5(PO4)3OH co-doped Eu3+/Yb3+ phosphor di kopantswe ka tsela ya keketso ya motjheso. Dipaterone tsohle tsa diffraction di kgema le dintlha tse tlwaelehileng tse boletsweng ke ICDD Card No. 00-033-1348. SEM image e bontshitse hore phoshwana e kopantse neteweke ya dikarolwana tse nang le sebopeho se sa lekaneng le dikarolwana tse nyenyane tse benyang tse takilweng ka hodimo ho dikarolwana tse kgolwanyane. Dikarolwana tse nang le diatomo tse boima ho backscattered electron detector di ne di le matla haholwanyane ho feta dikarolwana tse bobebe mme di bonahala di kganya hanyenyane. Phoshwana ya UC emission spectrum of Sr5(PO4)3OH:Eu3+,Yb3+ phosphor e ile ya hlokomelwa tlasa 980 nm excitation. Prominent red emission from Eu3+ ion e ile ya hlokomelwa ka ho hlaka ho 658 nm ka lebaka la tshebetso ya phetiso ya kgobokano ya matla. Photodynamic therapy e sebedisa dithethefatsi tse ikgethileng, tse bitswang photosensitizers, hammoho le kganya bakeng sa ho bolaya disele tsa mofetshe kapa kankere. Dithethefatsi di sebetsa feela kamora ho bakwa ho ba mahlahahlaha ke mefuta e itseng ya kganya kapa lesedi. Dithethefatsi tse ngata di etswa mahlahahlaha ke kganya e kgubedu. Red luminescence tse ekeditsweng ho tswa ho phosphors tse boletsweng ka hodimo di loketse ho hlahafatsa photosensitizers tse fapaneng bakeng sa phekolo ya kankere kapa photodynamic therapy. Photodynamic therapy activity e entswe ka ho sebedisa red emitting phosphors tse hlophisitsweng diphuputsong tsena hammoho le phthalocyanine jwaloka photosensitizer. Phthalocyanine e entswe mahlahahlaha ka wavelength ~670 nm. Diphetho tsa mosebetsi ona di hlaloswa ka botlalo kgaolong ya 10. ___________________________________________________________________ | st_ZA |
| dc.description.abstract | 𝑰𝒔𝒊𝒁𝒖𝒍𝒖 I-Phosphate phosphors iye yavela njengomndeni obalulekile wezinto ezikhanyayo ngenxa yezinga lokushisa eliphansi le-sintering, izikhala ezibanzi ze-band, ukuzinza okuphezulu kwe-thermal kanye namakhemikhali, namandla e-phonon aphakathi. Isakhiwo sazo singahlinzeka ngohlu olubanzi lokushintshwa kwe-cationic okungenzeka kube khona njengoba kunezindawo ezihlukene ezingalingani zama-ion ensimbi ezethula ubukhulu obukhulu kanye nama-coordination sphere. Ama-ion omhlaba angajwayelekile ane-doped phosphate compounds njengezinto ze-luminescence ziye zaphenywa kabanzi kuma-lattice ahlukahlukene ahlanganisa ama-phosphates. Kulolu cwaningo, izici zokukhanya ze-phosphate phosphor ehlukene ezifakwe i-Er3+, Eu3+, ne-Yb3+ zaphenywa. I-Er3+ ne-Yb3+ eyenziwe nge-singly doped, kanye ne-Er3+/Yb3+ co-doped Ba5(PO4)3OH phosphor powders ahlanganiswe ngempumelelo ngendlela yokuvutha kwe-urea. Amaphethini e-X-ray Diffraction (XRD) abonise ukwakheka kwe-hexagonal ye-Ba5(PO4)3OH ekhonjwe ku-ICDD (Isikhungo Somhlaba Wonke Sedatha Yokuhlukanisa) Inombolo Yekhadi 00-024-0028. Awekho amashifu aphezulu noma iziqongo zesibili eziboniwe eziphakamisa ukuthi izigaba ezimsulwa zenziwe zacwebezela. Isithombe se-Scanning Electron Microscope (SEM) sabonisa ukuthi izinhlayiya zazihlangene ndawonye zakha umumo oyi-ellipsoidal. I-spectra ye-Energy Dispersive x-ray Spectroscopy (EDS) eneziqongo eziqinile ze-Ba, P, no-O ibonwe iqinisekisa ukwakheka kwe-Ba5(PO4)3OH. Ukusabalalisa usayizi wezinhlayiyana ze-Ba5 (PO4) 3OH powder kulinganiselwa kusukela ekuhlaziyweni kwezibalo ngokulinganisa cishe izinhlayiya ze-10. Isilinganiso sobude nobubanzi bezinhlayiya bekungama-867 no-169 nm, ngokulandelana. Emuva kwesasasa kusetshenziswa i-laser engu-980 nm, iziqongo zokukhishwa okuningi endaweni eluhlaza kanye nesifunda esibomvu zibonwe zihambisana nokushintshwa kwe-ion ye-Er3+. Ngokuqhubeka nokusebenzisana ne-Yb3+ ukukhishwa okubomvu kuye kwathuthukiswa ngenxa yokudluliswa kwamandla ukusuka ku-Yb3+ kuya ku-Er3+. I-Ba5(PO4)3OH ehlanganiswe ne-Eu3+ kanye ne-Yb3+ phosphor ilungiswe ngendlela yokushiswa kwe-urea. Iziqongo ze-diffraction ze-Ba5(PO4)3OH zikhonjwe esigabeni esimsulwa se-hexagonal, okubhekiselwe kuNombolo Yekhadi le-ICDD 00-024-0028. Izithombe ze-SEM zibonise uguquko (kusukela ezindongeni, eziyisiyingi, ezifana nenaliti kuya ezinhlayiyeni ezingafananga) ku-morphology engaphezulu okwabangelwa ukukhishwa kwe-anneal kanye nokwengezwa kwama-dopants. Usayizi wezinhlayiya ubonakale umkhulu uma uqhathanisa nezimpushana ze-phosphor ezilungiselelwe njengoba zilungisiwe. Lokhu kungase kube ngenxa yokwanda okubangelwa i-anealing. Ivuthondaba ebanzi yesasasa elingu-240 nm nezinye iziqongo zenjabulo ezitholakala ku-~319, 360, 382, 395 kanye no-465-537 nm zabelwe izinguquko ze-Eu3+ ion. Iziqongo ezikhishwayo zibonwe ku-~589, 614, 651 naku-699 nm. Lapho usebenzisana ne-Yb3+, inani eliphakeme lokukhipha umoya libonwe ku-657 nm elabelwe izinguquko ze-Eu3+. Lokhu kube ngenxa yenqubo yokusebenzisana yokudlulisa amandla. Amasampula e-Er3+ kanye ne-Yb3+ ahlanganiswe ndawonye e-Ca5(PO4)3OH ahlanganiswa yi-urea indlela yokuvutha. Amaphethini we-XRD wezimpushana ze-Ca5(PO4)3OH kokubili njengoba elungisiwe kanye nalawo adonswe ku-800 0C abalulwe esigabeni esiyi-hexagonal se-Ca5(PO4)3OH esishiwo ku-ICDD Card No. 00-073-0293. Ama-micrographs e-SEM abonisa induku noma i-morphology efana nepuleti eyenza izimbali, izakhiwo ezinjengepuleti kanye nezinhlayiya ezincane ezinama-agglomerated phezulu kwamapuleti. Okwe-Er3+ iziqongo zokuphuma kwe-phosphors ezifakwe ngendlela eyodwa zibonwe endaweni eluhlaza ukusuka ku-517 -573 nm kanye nesifunda esibomvu ebangeni lika-653- 679 nm. I-Ca5(PO4)3OH:I-Er3+ phosphor yalungiswa kusetshenziswa ukugxila okuhlukile kwe-Er3+ kusukela ku-1-7 mol.%. Amandla e-photoluminescence anda ngokugxila okwandayo kusuka ku-1 kuya ku-3 mol%, futhi ehla ekugxilweni okuphezulu kwe-5 kanye ne-7 mol.% ngenxa yemiphumela yokuqeda ukugxila. Ukwengeza ukugxila okuhlukile (5-15 mol.%) kwe-Yb3+. Amandla okukhipha kuzo zombili izindawo eziluhlaza nesibomvu anyuke ngokugxila okukhulayo kwama-Yb3+ ions. Ukuthuthukiswa kokukhipha okuluhlaza kungase kube ngenxa yokwanda kwamathuba enqubo yokudlulisa amandla ezithombe ezintathu phakathi kwama-Yb3+ kanye ne-Er3+ ions. I-Ca5(PO4)3OH:Eu3+, Yb3+ phosphor powders ahlanganiswa ngendlela yokusha kusetshenziswa i-urea njengophethiloli. Amaphethini we-XRD wezimpushana ze-Ca5(PO4)3OH kokubili njengoba elungisiwe kanye nalawo adonswe ku-800 0C abelwa esigabeni esiyi-hexagonal se-Ca5(PO4)3OH okubhekiselwe ku-ICDD Card No. 00-073-0293. Osayizi bekristalu ababalelwe izimpushana ezilungiselelwe njengoba zilungisiwe kanye ne-annealed batholakale bengama-27 no-44 nm, ngokulandelana. I-UC emission spectrum ye-Ca5(PO4) 3OH:Eu3+,Yb3+ phosphor powder ibonwe ngaphansi kwe-980 nm excitation. Ukukhishwa okubomvu okuvelele okuvela ku-Eu3+ ion kubonwe ngokucacile ku-613 nm kanye neziqongo ezincane zokukhishwa kwe-547, 591, 654 kanye ne-697 nm. Ukukhishwa okubomvu okuvelele okuvela ku-Eu3+ kube ngenxa yokudluliswa kwamandla kusuka ku-Yb3+ ion. Ukudluliswa kwamandla okusebenzisana kusuka ku-Yb3+ ion kuya ku-ion eyodwa ye-Eu3+ kwenzeke ngokukhululeka okungenamisebe okusheshayo kuya esimweni se-metastable 5D0, futhi ukukhishwa kwe-Eu3+ ebomvu kwabonwa. I-Sr5(PO4)3OH i-co-doped Er3+/Yb3+ phosphor powders yahlanganiswa ngendlela yokuvutha. Iziqongo zephethini ye-XRD diffraction bezihambisana nedatha ejwayelekile ebalulwe ekhadini le-ICDD No. 00-033-1348. Isilinganiso sosayizi wecrystallite obaliwe sasingu-43 ± 2 nm. Ama-micrographs e-SEM abonise ukuthi i-powder yakhiwa izinhlayiya ezihlanganisiwe ezinemiphetho eyakha amajamo angama-hexagonal. I-agglomeration ibonise isakhiwo esinezimbotshana esibangelwa imvelo yokusabela komlilo okuhlobene nokuvela kwevolumu enkulu yamagesi. Phezu kwesasasa elingu-980 nm, i-Sr5(PO4)3OH:I-Er3+ ibonise amabhendi e-emission amaningi endaweni eluhlaza kanye nenani eliphakeme elincane kakhulu endaweni ebomvu. Isiqongo esinamandla sokuphuma esibomvu esinezihlukaniso ezimbili ezincane zibonwe ku-661 nm, kanye (651 kanye no-679 nm), ngokwenza i-co-doping nge-Yb3+ ion. I-Sr5(PO4)3OH i-co-doped Eu3+/Yb3+ phosphor powders yahlanganiswa ngendlela yokuvutha. Wonke amaphethini okuphazamisa afaniswe nedatha evamile ebalulwe yi-ICDD Card No. 00-033-1348. Isithombe se-SEM sibonise ukuthi impushana eyakhiwe inethiwekhi yezinhlayiya ezinobunjwa obungavamile kanye nezinhlayiya ezincane ezikhanyayo ezifakwe ebusweni bezinhlayiya ezinkulu. Izinhlayiya eziqukethe ama-athomu asindayo kumshini wama-electron ahlakazekile zazinamandla kunezinhlayiya zokukhanya futhi zibonakala zikhanya. I-UC emission spectrum ye-Sr5(PO4)3OH:Eu3+,Yb3+ phosphor powder ibonwe ngaphansi kwe-980 nm excitation. Ukukhishwa okubomvu okuvelele okuvela ku-Eu3+ ion kubonwe ngokucacile ku-658 nm ngenxa yenqubo yokubambisana yokudlulisa amandla. I-Photodynamic therapy isebenzisa izidakamizwa ezikhethekile, ezibizwa ngokuthi ama-photosensitizers, kanye nokukhanya ukubulala amangqamuzana omdlavuza. Izidakamizwa zisebenza kuphela ngemva kokwenziwa kusebenze izinhlobo ezithile zokukhanya. Izidakamizwa eziningi zenziwa kusebenze ilambu elibomvu. I-luminescence ebomvu ethuthukisiwe evela kumaphosphor ashiwo ngenhla afanele ukwenza ama-photosensitizer ahlukene ekwelapheni umdlavuza noma ukwelashwa kwe-photodynamic. Umsebenzi we-Photodynamic therapy wenziwa kusetshenziswa ama-phosphor akhiphayo abomvu alungiselelwe kulolu cwaningo kanye ne-phthalocyanine njenge-photosensitizer. I-Phthalocyanine yenziwa yasebenza ubude begagasi ~670 nm. Imiphumela yomsebenzi kuxoxwa ngayo esahlukweni se-10. ___________________________________________________________________ | isiZ_ZA |
| dc.description.sponsorship | National Research Foundation (NRF) | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/11660/7699 | |
| dc.language.iso | en | en_ZA |
| dc.publisher | University of the Free State | en_ZA |
| dc.publisher | Abstract in other languages 𝘚𝘤𝘳𝘰𝘭𝘭 𝘥𝘰𝘸𝘯 𝘧𝘰𝘳 𝘈𝘧𝘳𝘪𝘬𝘢𝘢𝘯𝘴, 𝘚𝘦𝘚𝘰𝘵𝘩𝘰 𝘢𝘯𝘥 𝘐𝘴𝘪𝘡𝘶𝘭𝘶 | |
| dc.rights.holder | University of the Free State | en_ZA |
| dc.subject | Phosphates powders | en_ZA |
| dc.subject | Rare earth ions | en_ZA |
| dc.subject | Upconversion luminescence | en_ZA |
| dc.subject | Energy transfer | en_ZA |
| dc.subject | Photodynamic therapy | en_ZA |
| dc.subject | Earths, Rare | en_ZA |
| dc.subject | Phosphors | en_ZA |
| dc.title | Upconversion of infrared to visible light in rare-earths doped phosphate phosphors for photodynamic therapy application | en_ZA |
| dc.type | Thesis | en_ZA |