ω ω ω Η Δ δ τορ ή Δ τρ ή " ", 2016
Η Ω Ω Ω Η Η Η Η Η Ω Ή ω ω Η Ε Ε Ε :., -,. (Ε ω ).., -,.., -,.., -,.., -,.., -,..., -,.
ί -.,..,,,.,.....,.,..,,..,,..,...,.,.,.,.,.,.,.,...,.
ί.,. Έ.., -.,, /,.,. Ω TiO2.,., (S/Na2S Na2S/Na2SO3)., S/Na2S S2 2-., Na2S/Na2SO3. Ω TiO2
(CuS, CoS, Cu2S).,, TiO2 WO3 BiVO4..
Abstract The aim of this study was the photoelectrochemical production of electricity and hydrogen using Photo-fuel cells. Photo-fuel cells are basically photoelectrochemical cells which can be used as an alternative way to convert solar energy into useful forms of energy photo-degrading simultaneously organic or inorganic wastes which are used as sacrificial agents. The basic configuration of such a cell comprises of a photoanode which is a light-absorbing semiconductor electrode and of a counter electrode in which an electrocatalyst is deposited. The two electrodes are immersed in an aqueous electrolyte solution which contains the sacrificial agent and are connected through an external circuit. When the photoanode is irradiated with photons that have energy equal to or higher than the band gap of the semiconductor, electron-hole pairs are created. The photo-generated holes in the valence band diffuse to the semiconductor-electrolyte interface where they oxidize the sacrificial agent, while the electrons are transferred through the external electrical circuit to the counter electrode and they take part in reduction reactions. In the case of Photo-fuel cells using organic sacrificial agents, ethanol was studied as a representative example of alcohols that can be found in different kind of wastes and biomass by-products. TiO2 was used as photo-anode both sensitized and non-sensitized in the visible spectrum with different kind of quantum dots. Also, alternative electrocatalysts were studied in order to subsistute platinum. Apart from the different kind of organic sacrificial agents, there are also inorganic coumpounds that can be used as very efficient hole acceptors, enabling the effective separation of the charge carriers. In the present study, two different sulfur mixtures were used (S/Na2S and Na2S/Na2SO3), high amounts of which are released from fossil fuel processing. In the first case, only electricity production was studied due to the fact that the photoelectrocatalytic efficiency of H2 production is very low in solutions containing only sulfide ions. This is attributed to the formation of disulfide ions, S 2- which exhibit a less negative reduction potential than protons. In the case of Na2S/Na2SO3 mixture, both photoelectrochemical electricity and hydrogen production were studied. TiO2 was again used as photo-anode combined with different quantum dots whereas in that case metal sulfides (CuS, CoS, Cu2S) were studied as electrocatalysts because platinum is unstable and increases the charge carrier transfer resistance in the presence of sulfur mixtures.
Finally, for the photoelectrochemical production of hydrogen, in addition to TiO2, WO3 and BiVO4 were synthesized and studied as well. These materials are medium band gap semiconductors which exhibit better photocatalytic activity than titania due to their visible light absorption.
ό Ε ω :... 1 1.... 2 2.... 3 3.... 5... 8... 9 Κ 1: Ε ω ω ω... 11 1.1... 12 1.2... 15 1.2.1 Ά... 15 1.2.2... 15 1.3 Fermi (Fermi Level)... 16 1.4... 17 1.5... 19 1.6... 20 1.7 TiO2... 23 1.8 TiO2... 27... 29 Κ 2: ω... 33... 34 2.1... 35 2.2... 39 2.2.1... 39 2.2.2... 43 2.3 /.... 44 2.4... 48
2.5... 54 2.5.1... 54 2.5.2 ph... 54 2.5.3... 55 2.6... 56... 62 Κ 3: Π... 68... 69 3.1... 69 3.1.1... 69 3.1.2 TiO2... 70 3.1.3 TiO2... 74 3.1.4 WO3... 77 3.1.5 BiVO4... 78 3.2... 79 3.2.1 Pt... 80 3.2.2....81 3.2.3... 82 3.2.4 Pt FTO... 83 3.2.5 FTO... 84 3.3... 85 3.4 ΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙ...86 3.4.1... 86 3.4.2... 87 3.4.3... 90 3.4.4... 91 3.5... 93 3.5.1... 93
3.5.2 (IPCE) 93 3.5.3... 94 3.6... 96 3.7... 98 3.7.1 (SEM)... 98 3.7.2... 98 3.7.3-99 3.7.4 Π (X-ray diffraction, XRD)... 101 3.7.5 Π... 102... 104... 106 Κ 4: Φω ω ω ω ω.. 107... 108 4.1 X... 108 4.1.1 TiO2... 108 4.1.2... 111 4.1.3 TiO2 Π... 115 4.1.4 - (UV-Vis DRS)... 117 4.1.5 CdS/TiO2 UPS... 122 4.2... 124 4.2.1... 124 4.2.2 GMC-S-X.. 127 4.2.3 XPS GMC-S-X... 128 4.3... 130 4.3.1 ( )... 130 4.3.2... 131
4.3.4... 135 4.4 TiO2... 143 4.5... 155... 163 Κ 5: Φω ω ω ω ω ω 166... 167 5.1... 167 5.1.1 (DRS)ΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙΙ..ΙΙΙΙ.167 5.1.2 Raman... 171 5.2... 173 5.2.1... 173 5.2.2 Cu2S Π... 177 5.3 CdS CdS/TiO2... 177 5.4 TiO2... 181 5.4.1 ZnS/CdSe/CdS/TiO2... 181 5.4.2... 186 5.5... 192... 199 Κ 6: Ε ω ω ω... 202... 203 6.1 WO3 BiVO4... 204 6.2... 209... 223
... 224... 227... 228... 229
ή ί ί ή ί ή 1: ή (816000 Km 2 ) ά ί ϊ ά ή ό % ή ή ύ ί 20 TW [1]. - 1 -
1. ό ό ύ ή., (, ), [2]. 56% ( ) 2010 2040, US Energy Information Administration (US-EIA) [3] ( 1)., (,, ) 85% [4],. ή 2: ό ώ ά έ έ - 2040 [3]. - 2 -
2. ώ έ έ.,. ( ) (United States Environmental Protection Agency) [5].,,..,., [6,7]., [8]. ( ). : Ε :. Η Θ. ( ). - 3 -
Υ Ε :. (,,,, ).,. ω Ε :,.. ( ). :, ( ).. (,,..) (,..). Η :.,..,. - 4 -
3. ή έ ί ή 3β10 24 J, 10.000 [9,10]., 100.000 TW, ( 3),. ή 3: ά ή ί. 2012, 7 18 TW [11].,,., [12]. Π 1. - 5 -
ί : ή ί ά ό έ ό ά ί ώ ώ [1]. ή έ ύ TW) ή Α σ - % ς Α 4 ς ς σ ς. Υ 1-2 Τ ς, TW. Γ ω 12 Μ σ σ. Α σ σ Π 10 ς ς GW/ ώ ς. Ε ό ό 10 Α % ς ς ς ς. Α, % ς Η >20 ς ς ς ϊ σ σ σ ς %. Έ 20 TW, 10% 816000 m 2 900x900 m 2 ( 1) [1].,.,,. (Solar-Thermal System). Έ.,,. - 6 -
(Photovoltaic Systems).,,. 35-40% [13]. (Photoelectrochemical Systems),,.,., 1839 Edmund Becquerel ω ( ) [14]. 1954 1972 Fujishima Honda [15].. Ό,,. ( ),., [16].,,.. - 7 -
,. /..,. ό ή.,. - 8 -
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ά 1 ή ί ώ ή 1.1: ό ά έ ύ ώ ό ά ά ά ύ [1]. - 11 -
1.1 ά ά ώ..,,,. Ό,. ( 10 22 Π 10 23 cm -3 ).,,., ( 1.2).,. (Valence band, VB).. - 12 -
ή 1.2: ό ώ ώ ό ί ύ ό [2]. ω (Conduction band, CB)., ( nergy band gap, Eg) [3]: Ε = E E V ev (1.1)..,.,.,.,, - 13 -
.. (Eg > 4 ev), ω (insulator)., ω (conductors).,. ω (Semiconductors),.,, ( ) [4,5].,. 1.3. ή 1.3: έ ώ ό ά έ, ύ ύ. - 14 -
1.2 ί ώ 1.2. Ά έ ί,. ω (direct semiconductor).,.,,, k [6]. ω (indirect semiconductor).,. (defect energy state) [7]. 1.2.2 ί ί ί. Έ,, ω (Intrinsic semiconductor). Si, Ge InAs, SiC, GaAs [3]. ω ω (Extrinsic semiconductors) ω ω, TiO2, ZnO NiO. Έ ( ),, - 15 -
. -n -p. ( -n ),,., -p [4]..,., -.,,., [8,9]. 1.3 ί Fermi (Fermi Level).,. Fermi Fermi (Fermi energy level), ½.. Fermi,., Fermi ( 1.4).,, Fermi - 16 -
. n-, Fermi, p- Fermi ( 1.4). ή 1.4: έ έ Εκχςξ έ ώ ό έ ή ό ή ό ύ n ύ p. 1.4 έ ώ ώ έ ά,. e - h + Φ.,, - 17 -
., y e - ( ) (Normal Hydrogen electrode, NHE). + / 2 4,5 ev., ph., -59 V ph : =. (1.2) 1.5. ή 1.5: έ ώ ώ ά ύ ή ό ύ ph=1 ά ά έ ά [10]. - 18 -
1.5 έ ύ ό ό Ό,.., : (1.3) Planck. (threshold wavelength),, : = = (1.4), (h + ): Ημιαγωγ ς h + h +,. Έ, e - h +. Έ,.,., - [2,11]. 1.6 - Πn Πp. - 19 -
ή 1.6: ή ί ύ ί - ή ά ύ/ ύ ό ύ n ί ί ύ p ί ώ [12]. 1.6 ό ώ ώ. : (1), (2), (3), (4) (5) [13,14].,.,, TiO2, - 20 -
Si. 1.7 1.5 ( 1.5) 1., 1 3 ev Φ (Eg>2.2 ev)., (Eg>1.0 ev).,. ή 1.7: ά ύ ό AM 1.5 έ ό ά ύ [15]. 1 ΑΜ 1.5: αφο ά σ ο ια ό φ ς ό ς α ό α α ί αι σ ιφά ια ς ς αι αφού ο φ ς ια ά ι ο ιά ή ο ς 1.5 φο ές ο ά ος ς α όσφαι ας [16]. - 21 -
.. [17].,, /..,. Ό,, /..,. Έ,, (.. TiO2, ZnO), (.. CdS, ZnS) (.. Ge3N4).,. n-, TiO2, WO3, SrTiO3, ZnO ZnS,..,.,, CdS, PbS - 22 -
CdSe.,,. p-,, [18]. 1.7 TiO2 ό έ ί, TiO2.,,. Έ,. -n, (anatase), (rutile) (brookite) ( 1.8). TiO2. [19] 700 όc., [20]. Π 1.1. TiO2, [21-23]. - 23 -
ή 1.8: έ έ TiO2: A) ή (a=b= 4,5937 Å, c= 2,9581 Å), ί (a= 9,16 Å, b= 5,43 Å, c= 5,13 Å), ά (a=b= 3,7842 Å, c= 9,5146 Å) [24,25]. ί 1.1: έ ό ώ ώ ά ί [2], [26]. g (ev) ECB (V vs NHE, ph=0) EVB (V vs NHE, ph=0) ά 3.23-0.32 2.91 ή 3.02-0.11 2.91-24 -
2.,.,, [27]. TiO2, silica gel,,,, [28-30].. TiO2,,,,., TiO2, Φ. (chemical vapor deposition), (hydrothermal deposition), - (sol-gel method) [31-34].,,. (electrodeposition), (dip coating), doctor blading spin coating TiO2. 2 Ως ο ής α α ί αι φ ο α ά σ ό ο ο α α ύ ς β ίσ αι σ σ ά ο φή αι ο φ ο α α ό ο σύσ α ί αι σ ή ή αέ ια φάσ. - 25 -
TiO2 Degussa P-25 3:1. Degussa P-25 Π 1.2.,, [2]. Degussa P-25. ί 1.2: έ έ ό ά, ί ά έ Degussa P-25 [35]. BET surface are (m 2 /g) Ό ό (cm 3 /g) Μέ ά ό (nm) ά 267.0 0.37 5.4 ή 4.5 0.02 10.5 Degussa P-25 65.3 0.17 12.1-26 -
1.8 ή ά TiO2 TiO2 [15, 36, 37]. Ό, TiO2,,. : έ TiO2: io + hv e + + h V 1.9 TiO2 -.,. ή.9: ό ί ύ ί - ή έ έ ί TiO2 ό ύ ό ά [38,39]. - 27 -
ϋ CO2 H2O. ( ϋ) (2.80 V) [38,39]. : h + V + CO + O h + V + O O + + ΟΗ + CO + O Ό.,, 2 - HO2 H2O2 [40-42]. - [27,43]: e + Ο Ο Ο + ΟΗ ΗΟΟ ΗΟΟ + e O OO + + O - 28 -
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ά 2 έ έ ώ ώ ή 2.1: ό ά ύ ύ [1]. - 33 -
ή,, ( ) ( ),. ( ).,.,., [2]. ( 2.2).,,., -., / H + H2., [3]. - 34 -
ή 2.2: ή ά ύ ύ ί ί ό ώ ά ά ό έ ύ. 2.1 ά ά ά ύ.. + 2 (0 V vs. NHE ph=0) - 35 -
2 2 (1.23 V vs. NHE ph=0) ( 2.3)., 1.23 ev. ή 2.3: έ έ ώ έ ό ό ύ ί ά ύ [4]. (1.23 ev) (0.3-0.4 ev) [5] (0.4-0.6 ev) [6]., 1.9 ev, 650 nm. 2.4.,,., CdS CdSe. S 2- Se 2- - 36 -
[7]: Cd v e + + h V + Cd + h V Cd + +S ή 2.4: ό ά έ ύ ώ ό ά ά ά ύ [8]., : + + +, + +, E o o o E = +. V vs. N E =. V vs. N E, : + + + +, + +, E o o o E = +. V vs. N E = +. V vs. N E - 37 -
Gibbs : =. : : : Faraday : (T=298 K, C= 1mol/L P= 1bar),, Gibbs = /. 2.5. ή 2.5: ό ί ί ί ό ώ ά έ ό ί έ ύ ί ό ά [9]. - 38 -
2.2 ά ά ή ό ώ Έ.., (sacrificial agents) e -, -., O2, [10,11]., H2. Ω [7].,. ω (Photo-fuel cells).. 2.2.1 έ ό ώ [12-16]. - 39 -
,,... / ( ) CO2 2 ( Ο2) CO2 H2O ( O2) [17]: ί : C O + κ z O κco + κ z + λ ί : C O + κ + O κco + λ O ( 2 -, 2,, 2 2). - (photo-reforming)., ( G = 237 J/mol), Gibbs. e -. - e -. - TiO2 CO2. Ό, 2,.,. / ( ) : Η Ο + h + O + + O + h + O - 40 -
.,.. TiO2, ( ).., CdSe TiO2 S 2- /SO3 2- S2/S2 2-.,,. Π 2.1., : + + Ό, CO2., ph. ph, + ( ) 2 ( V )., ( OH - ), OH - ( V). (V )., -., - 41 -
3 2 : + + Ό, ( VIII IX). ί 2.1: ά ί ί ί ύ TiO2 ό ό έ [12]. Φω : h TiO 2 e h (I) e - 2 ( ) : O O HO HO H O OH OH (II) e + H e + H e 2 2 2 2 2 2 : C2H5OH + 3H2O + 12h + 2CO2 + 12H + ( ph) (II ) OH - + h + OH C2H5OH+12OH 2CO2 + 9H2O ( ph) (IV) : C2H5OH+2h + CH3CHO+2H + C2H5OH+h + C2H5O +H + (V) Κ ph (0.00 V ph=0) 2H + + 2e - H2 ph (-0.77 V ph=13) 2H2O + 2e - H2+2OH - (VI) (VII) ph (1.23 V ph=0) 2H + +½ O2 + 2e - H2O (VIII) ph (0.46 V ph=13) H2O+½ O2 + 2e - 2OH - (IX) ( ) 2 (ethanol reforming): C 2H 5OH + 3H 2O 2CO 2 + 6H 2 2 (ethanol mineralization): C 2H 5OH + 3O 2 2CO 2 + 3H 2O (X) (XI) - 42 -
2.2.2 ό ό ώ,. : H2S, S 2Π /SO3 2-, Br Π, I Π, CN Π Fe 2+. S, S 2- SO3 2-,. ( S 2- /SO3 2- ). Έ S 2- / SO3 2-.,. Έ CdS/TiO2, Cd 2+ S 2- CdS [10].,, S/Na2S Na2S/Na2SO3., S 2- S2 2- S 2-. : + + +, S2 2-. Ό S 2- /SO3 2-, SO3 - ( - 43 -
). SO3 2- SO4 2- S2O6 2- : + + + + ή + + + + S 2- Na2S, S2 2- SO3 2- : + + + + + +, S2 2- [10, 18, 19]. 2.3 ά ύ/ ύ ό ί Ό,.. ph, / /.. - 44 -
Ό, H + OH -. : Μ ΟΗ k O + + a + Μ ΟΗ + k + a O ph ( 2.6).,,,. ph (point of zero charge, pzc) [20]. ή 2.6: έ ή ί ί έ ά TiO2 ί ύ ύ ί ά ph ύ. pzc TiO2 ί 6.0 ± 0.2 [20-22]. e - ( h + ). Ό, /., Fermi Fermi. (e - n- h + p- - 45 -
)., Fermi n- (. Fermi ) e -.,, e -, (depletion layer, DL) ( 2.7) [9]. ή 2.7: ί ά ά n- ύ ό ό έ ή ά ύ [23]. (Space Charge layer (SCL)). 2.7 [23,24]., /.,. Helmholtz Helmholtz (Inner Helmholtz plane (IHP)) e - / - 46 -
, Helmholtz (Outer Helmholtz plane (OHP)) ( 2.8). Helmholtz ( 2-5 Å),, Å., Gouy-Chapman 30 nm. w Helmholtz [26, 26]., Csc, CH CG, Helmholtz Gouy-Chapman [20, 23]. ή 2.8: ό έ ά Helmholtz ί ά ύ/ ύ. ό ί Helmholtz (IHP) ί ό ό + - έ ά ύ ό ί Helmholtz (OHP) ά έ έ ό [9]. - 47 -
2.4 ά ύ ύ έ ό ή - (I-V curves)...,.,,. ω (short circuit current, ISC).,, (open circuit potential, VOC). Έ (Pmax) -, Pmax= ( V)max. 2.9 -. - 48 -
ή 2.9: ύ ύ ά ό ύ ύ ά ό ό.. (Fill Factor, FF). : F. F. = V x SC V OC., 0 1 ( ). - 49 -
. (efficiency, n) (Pin) : n% = V x i % = x i %. (quantum efficiency),..,. 0, 1.,, 1.,, 0., ( 2.10).,. - 50 -
ή 210: ή ή ύ ή ό ό ύ ύ.,. ω (External Quantum Efficiency). (Incident Photon to Current Efficiency, IPCE) : =. Ό, : : : - 51 -
ω (Internal Quantum Efficiency). (Absorbed photon-to-current Efficiency, APCE). APCE IPCE : = =. Ό A, R, T (Absorption), (Reflectance) (Transmission)., (Solar to Hydrogen Efficiency, STH%) : % =. %. Ό J, P 1.23 V ( ph=0).. Ό,.. 2.11. - 52 -
ή 2.11: ά ά ό ό ή ό STH Efficiency) ό ύ ή ύ ά ά ό ά ί ώ ώ ό ί ί. mw/cm 2 ) [27]. - 53 -
2.5 ά ά ό ό ύ ύ,. ph. 2.5.1 ά.,. [28]. : O + λ κ h+ η ε τρο της κ / a + λ O Gibbs [9]. 2.5.2 ph, ph., - 54 -
ph, Φ [29]., ph. Ό, ph 0. pzc TiO2 [21],. Ό ph (ph>pzc) ph pzc (ph<pzc) [29,30]., < : io + + io +, p T 2 + =. > : io + O io + O, p T =., ph [31]. 2.5.3 ί.,., 80 C. 80 C, 0 C [29]., 20 C - 80 C [32]., - 55 -
,. 2.6 Μέ ί ή ά TiO2.. Έ.,, [24]., /. Έ. /.,. (Highest Occupied Molecular Orbital, HOMO) (Lowest Unoccupied Molecular Orbital, LUMO) [33,34]., [35], [36], [37].. ( 2.12) [38]. - 56 -
ή 2.12: ή ά ώ ώ ά ά ύ ύ ύ [39]. doping,, [9]. doping e -, e - [40,41]. doping TiO2 Cu, Ni, Co, Fe, Mn, Cr, Au, Ag, Pt [42-44]. Ω,. TiO2 TiO2 ( 2.13). Φ, e -., - 57 -
[45].., C, N, B, P, F, I TiO2 [46,47]. Ό, ( 2.13). doping., 2 [48]. 1-2%, 10 21 cm -3. [9]. ή 2.13: ό ά TiO2 ί doping (hv1) ό ί έ hv2 έ hv3) [49]. - 58 -
Έ TiO2, [50]. TiO2 [51]..,, e -., TiO2 Η Θ e - [52]., (Quantum Dots) [51].,, [53-55].. 2.14. - 59 -
ή 2.14: ά ί έ ύ ώ ώ ύ έ. ί έ ί ί : ΒιΣ σς, ΒιΣκ σς, ΒιΤκ. σς, ΟηΣ. σς, ΟηΣκ. σς, Sb2S3 σς, Ση2Se3 σς [56]. Έ TiO2 CdS n- Eg= 2.4 ev., CdS/TiO2,., e - CdS., TiO2, e - TiO2 CdS., ( 2.15). - 60 -
ή 2.15: ό ά ό ί TiO2 έ ί CdS ί ά ί ά ό ύ ύ., [57,58]. Ό, TiO2. - 61 -
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ά 3 έ έ ά ή 3.1: ή ά ά ί ί ί ή ό έ ή ό ύ ό ώ ά ό. - 68 -
ή. Έ...,. 3.1 ή ό ώ 3.1.1 ό ί ώ.,.,., (SnO2:F, Fluorine doped Tin Oxide, FTO) (In2O3:Sn, Indium Tin Oxide, ITO). (>80%). Π 3.1-69 -
. FTO. ί 3.1: ά ά ά ώ ά FTO ITO. ά ώ ό έ ό (S/cm) έ έ cm -3 ) ό έ (cm 2 /Vs) ή ό έ ( C) SnO2:F (FTO) ~1x10 3 ~4x10 20 ~30 < 700 C In2O3:Sn (ITO) ~1x10 4 ~10 21 ~40 < 350 C 3.1.2 ή ί TiO2 FTO ( : 8 Ω/ ).,. TiO2,..,., TiO2 (sol-gel) Degussa P25. (nc-tio2) :.,,. - 70 -
. sol-gel TiO2.,,., sol-gel TiO2 : 3.5 gr Triton X-100 (t-oct-c6h4-(och2ch2)xoh, x= 9-10) 19 ml (CH3CH2OH)., 3.4 ml (CH3COOH) 1.8 ml (Ti[OCH(CH3)2]4) 20 min.. Ω 3 [1].,., (Triton X-100). Triton X-100 - ( 3.2). 3 Οι σ ο ι ές α ι άσ ις ό σ ς αι ο ισ ού ο αϊσο ο ο ι ίο ο ι α ίο ί αι οι ής: Υ ρό υση: Ti (OCH(CH3)2)4 + H2O Ti (OCH(CH3)2)3OH + (CH3)2CHOH, Πο υ ρισ ός: Ti (OCH(CH3)2)3OH+Ti (OCH(CH3)2)4 Ti2O(OCH(CH3)2)6+(CH3)2CHOΗ αι σ ο ι ή α ί ασ ς ό ς ι ασίας ί αι: Ti (OCH(CH3)2)4 + 2H2O TiO2 + 4(CH3)2CHOH. Η αφή ο ισο ο ο ι ίο ο ι α ίο ο ό ο ί σ βίαι ό σή ο αι ά σ α αβύθισ ι ή α ος ο ι ίο ο ι α ίο TiOH ο ο οίο σ σ έ ια ο ί αι αι ο ί σ ο σ α ισ ό ά ο έθο ς σ α ι ί TiO 2 α ο οιό ο φ ο ή. - 71 -
TiO2. ή 3.2: ή ή ύ Triton X-100. (dip coating) sol-gel TiO2 ( 3.3).,,.,,.,, Π 550 C ( 20 C/min) 10 min... 170 nm FE-SEM. - 72 -
ή 3.3: ί ό ί έ ί ό ιξυ θτζωξσμ. sol-gel TiO2., Degussa P25 / (3:1). : 0.3 g Degussa P25, 0.5 ml CH3COOH 5 min., 1.5 ml.., CH3CH2OH., 1 ml 10 1.25 ml CH3CH2OH 6 ( 17.5 ml ). 50 ml CH3CH2OH. 10 g Terpineol (C10H18O) 2.82 g CH3CH2OH (10% w/v ). 35 C. - 73 -
TiO2 doctor blading ( 3.4) 550 C ( 20 C/min) 10 min. 3.4 m - 2. ή 3.4: ή ά ύ ί έ doctor blading [2]. 3.1.3 ί ί TiO2. CdS, PbS ZnS, ω (Successive Ionic Layer Absorption and Reaction, SILAR method).,,. TiO2.,. - 74 -
3.5. Silar. ή 3.5: ή ά ό ώ ώ έ ή ό ί ό SILAR method) [3]. CdS/TiO2: CdS 3 Cd 2+ : Cd(NO3)2 4H2O (98%), 3CdSO4 8H2O ( 98%) Cd(CH3COO)2 2H2O (98%). S 2- Na2S 9H2O ( 98%)., 0.1. TiO2 5 min.,., 5 min. Silar. - 75 -
CdS 10. ZnS/TiO2: ZnS Silar : 0.1 Zn(NO3)2 6H2O 0.1 Na2S 9H2O. 2 Silar. CdS-ZnS/TiO2: CdS-ZnS 0.1 Cd(NO3)2 4H2O Zn(NO3)2 6H2O. S 2- Na2S 9H2O., 10 Silar. PbS/TiO2: PbS TiO2 CdS ZnS., 0.1 Pb(CH3CO )2 3H2O 0.1 Na2S 9H2O. TiO2 2 Silar. CdSe, ZnSe Sb2S3 (Chemical Bath deposition, CBD). CBD,. TiO2. TiO2 [4,5]. CdSe/TiO2:, 0.08 Se 0.02 Na2SO3 ( - 76 -
, Reflux) 80 C 15 h., 0.08 CdSO4 8/3H2O 0.12 N(CH2COONa)3 H2O.,., (5 C) 4 ½ h. ZnSe/TiO2: ZnSe CdSe 0.08 CdSO4 8/3H2O 0.08 Zn(NO3)2 6H2O. CdSe-ZnSe/TiO2: CdSe-ZnSe, CdSe CdSO4 8/3H2O Zn(NO3)2 6H2O. Sb2S3/TiO2: 2 ml Sb2S3 ( 1 ) 20 ml Na2S2O3 ( 1 ).,, 5 C 80 ml., TiO2 10 C 2.. QDs. : CdS-ZnS/TiO2, CdSe/CdS/TiO2, ZnS/CdSe/CdS/TiO2, CdSe-ZnSe/TiO2, CdS/PbS/TiO2. 3.1.4 ή ί WO3 TiO2 WO3. - 77 -
WO3 FTO., sol-gel WO3 : 0.4 g W (10 m, 99.99%) 3 ml H2O2 (30 wt% H2O)., H2O2 Pt ( 12 h)., 3 ml CH3CH2OH 0.3 g Triton X-100., FTO doctor blading 500 C (20 C/min) 10 min. - 5 WO3. 4.5 mg/cm 2. 3.1.5 ή ί ΑξΦO4 Έ BiVO4 FTO.,. sol-gel BiVO4 : : 0.12 Bi(NO3)2 5H2O CH3COOH 0.12 V(C5H7O2)3 CH3COCH2COCH3., 1 ml Triton X-100. 0.025-0.5 g/ml. FTO doctor blading 500 C (20 C/min) 10 min. - 3 350 nm. - 78 -
. ή ό ώ 4,.. Ω,,.,. Έ, ( ) : (1) NiO, (2) NiO (3) (graphene-based sulfur-doped porous carbon nanosheets). WO3, Pt FTO.,, : (1) CuS, CoS FTO (2) Cu2S. 4 Ως έ ο ό ο ο ί αι ο ά ισ ο έ ο ο α αι ί αι ια α ι ήσ ι έ α ό ιο ις ι ές ά ις ο ι ού σ α ό α ό α ό οι α φο ία έσα σ έ α έ α ο αι α α ο α θ ί ύθ ο α ό ο α ι ό έ α. - 79 -
.. ό ί Pt ύ ά,. Έ (Carbon Cloth, CC)... :, 2.46 g (Vulcan XC 72) 60 ml 0.8 ml PTFE (polytetrafluoroethylene, 60 wt% H2O) ( C:PTFE=70:30) mixer (2500./min)., carbon cloth 80 C 30 min. Έ, 340 C 30 min PTFE., 0.0599 g Pt C (30% Pt on Vulcan XC 72), 0.52 ml (Nafion, 5 wt. % ), 0.573 ml 0.45 ml. 80 C. 0.5 mg Pt/cm 2 ( ). - 80 -
3.2.2 ή ή ά ύ ώ,,.,. (Multiwalled carbon nanotubes, MWCNTs)., 0.35 nm 2 100 nm cm. ( ).,. MWCNTs : 7 g 3-150 ml CH2Cl2 1.50 g. 20 h, PTFE ( : 0.2 m) CH2Cl2. 150 ml CH2Cl2 3-. 80 C. films PTFE 230 m 7 cm [6].. NiO Carbon Cloth., 1 g NiCl2 1 g Triton X-100., 3 ml 6 ml., 400 C 30 min. - 81 -
3.2.3 ύ ύ ά έ έ έ ί,. Jiao Tong ( ). 3.6 :, (Reduced graphene oxide, RGO) p-. RGO, (DMF, 1.0 mg/ml),., 1,3,5-2,5- RGBr, DMF Hagihara-Sonogashira., GMP-S, 700, 800 900 όc 2 h (GMC-S700, GMC-S800 GMC- S900). : 10 mg (GMC-S700, GMC-S800 GMC-S900) 1.3 ml 0.5 ml., 0.1 ml (PTFE, 60 wt% H2O). CC 340 όc 20 min. 10 cm 2 (3.0cm 3.3cm) 5 mg [7]. - 82 -
ή 3.6: ή ί ύ GMP-S GMC-S. (i) Sodium dodecylbenzenesulfonate, N2H4 H2O, 100 C, 8 h, (ii) 4-bromobenzenediazonium tetrafluoroborate, 0 C έ ί ί, 2 h, (iii) Ar, Pd[(PPh3)4], CuI, Et3N, DMF, 80 Β, 3 days (M1: 1,3,5-triethynylbenzene; M2: 2,5- dibromothiophene), (iv) Ar, ί ί έ 700, 800 and 900 Β, 5 Β/min, 2 h. Ω GO RGO ί ί ί έ ί ί ί [7]. 3.2.4 ό ί Pt ί FTO WO3 BiVO4, Pt FTO.,, (Elcocarb C/SP (Solaronix)) FTO doctor blading - 83 -
450 C 30 min., Pt Diamminedinitritoplatinum(II) (3.4 wt.% NH4OH) CH3CH2OH ( 99.8%) 450 C 15 min. Pt 0.1 mg/cm 2. 3.2.5 ό ύ ά ί FTO,., [8]., (CuS, CoS) FTO Cu2S. CuS/FTO: FTO,. CuS FTO. 0.5 mol/l Cu(NO3)2 H2O CH3OH 1.0 mol/l Na2S 9H2O - (50% v/v)., Cu(NO3)2 H2O.,.,. 15. CoS/FTO:,. CoS FTO., 5 mmol/l CoCl2 6H20 0.5 mol/l NH2CSNH2 (Thiourea). Έ, 4-84 -
ph 6., FTO, - Ag/AgCl. 1 cm.,, 1.2 V +0.2 V 5 mv/s., FTO CoS, 100 όc 20 min. Cu2S/ :., HCl (37%) 70 όc 5 min., 1.0 mol/l Na2S 9H2O 70-80 όc 1.0 mol/l S. 5-7 min 100 όc 10 min.. ύ ί ί,,.,,.,. ph.,, NaOH - 85 -
., Na2SO4, LiClO4, NaClO4 NaCl., Na2S, Na2SO3 ( S/Na2S). Ό ( ). : Na2S 9H2O 1M 70-80 C. Έ, S (99.998%) Na2S 1. 3.4 ά ή ή ώ ή.,,. 3.4. ή ή ί., Φ - 86 -
., ( Xe, Oriel 450W) 100 mw/cm 2. Xe 3.7. ή 3.7: ή ή ά Xe ύ ό [9]. 3.4.2 ή ώ ή Έ.., 5.5 x 6.0 x 5.5 cm Plexiglas ( 3.8). - 87 -
ή. : ή ά ή ή ά ή ώ ή ύ ύ ί. 2.5 3.0 cm. 0.5 cm.,.,.,,., SiO2-88 -
. Π 3.2 25 mm 2 mm. ί 3.2: ή ύ ώ ί VitraPOR (Robu, Germany) ή ά ή ί ύ ά. Silica, SiO2 80.60% Magnesium oxide, MgO 0.05% Boric oxide, B2O3 12.60% Iron oxide, Fe2O3 0.04% Sodium oxide, Na2O 4.20% Calcium oxide, CaO 0.10% Alumina, Al2O3 2.20% Chlorine, Cl 0.10%,, Plexiglas, 5.0 x 4.5 x 3.5 cm 1.5 x 1.5 cm., 1 cm. Ό, Pyrex Glass. 55 mm 10 cm ( 3.9).. Ό, 5. 5 Για ιο ία ι ής ό σ ς chemical bias) α ύ α ό ο αι αθό ο ο ού α σι ο οι θού ο ύ ς ιαφο ι ές ι ές ph. Σ α ή ί σ σ ο ια έ ισ α ς α ό ο ο οθ ί αι ά οιος βασι ός ο ύ ς.. NaOH) ώ σ άθο ο ό ι ο ιά α (.. H 2 SO 4 ). - 89 -
ή. : ή ά ή ύ ά ή ά ή ί ό. 3.4.3 ά ώ ή, ( 3.10). - (linear sweep voltammetry), AUTOLAB PGSTAT 128N NOVA 1.9. - 90 -
ή 3.10: ή ά ή ώ ή. 3.4.4 ή ί ά Ό,.., (Reference electrode)., ( ). Π 3.3. 3.11. - 91 -
ί 3.3: ά ά ί ά ή. ό ά ά ή ό vs SHE) RHE (Reversible Hydrogen electrode) SHE (Standard Hydrogen electrode) ό ύ ύ ύ έ έ H2) [H + ] = 1.18 mol/l p(h2) =10 5 Pa E0= 0.00 E0= 0.0-0.059 x ph 0.1 M KCl 0.289 Ag/AgCl 3 M KCl 0.210 έ KCl 0.198 ή. : ή ά ί ί ύ ή ό ώ ί ά ό ό ί ό ά. - 92 -
3.5 ί ώ ή 3.5.1 ή ή ή ί,, ( ). -,. 5 mv/s. ( )..,,, [10].,. 3.5. έ ό ή ί ύ IPCE).,.. - 93 -
. 3.5.3 ί ή έ (Electrochemical Impendance Spectroscopy),.. /,., ( ). ( ),, ( ). : = +. j (j j = -1).,.., Nyquist. Nyquist, =,. 3.14 Nyquist. - 94 -
ή 3.14: ά Νyφuξψω ύ ό ύ ά ί R) έ ή C) έ ά. Έ - Randles. (Rs) / ( 3.15). ή 3.15: ύ ό ύ Randles (Ref. el.: ό ά, WE: ό ί, CE: ό. Rs,. Rp - 95 -
, - (Rct).,, Cdl. 3.6 Μ ή ή ί ό, ( Xe, Oriel 450W) 100 mw/cm 2. SRI 8610C, ( Silica Gel). (Molecular sieve) silica gel H2, O2, N2, CH4 CO., 0.25% 2 Ar. :,. Ω Ar Φ (21 cc/min). 10-, 600 C. Silica Gel Molecular Sieve.,, (Thermal Conductivity Detector, TCD)., ( 3.17). - 96 -
ή 3.17: έ ό ά ή ή ό. PeakSimple 3.56. Έ 3.18. ή 3.18: ή ό ή έ ί. - 97 -
3.7 έ ύ ά 3.7. ή ί ά SEM) (Scanning Electron Microscopy, SEM)..,.,. (x y).,,, (secondary), (backscattered) -. SEM, ( ) Zeiss SUPRA 35VP 1.5 nm 20 V 2nm 30 V. Π (EDX) (QUANTA 200, Bruker AXS). 3.7. ή ί ό (Transmission electron Microscopy, TEM). Ό, - 98 -
,., ( ),.,. EM, Έ. 3.7.3 ί ά ά ύ- ώ - (Diffuse Reflectance UV-Vis Spectroscopy).,. Ό 3.19,. ή 3.19: ή ά ή ά ά ό ό ώ. - 99 -
DRS,.. (.. BaSO4).,. 3.20. ή 3.20: ή ό ά ό έ ά ά ί ή [10]. Ω - 190-900 nm.., 300-800nm,. Ω FTO. ( ) - (UV-VIS Spectrophotometer, Shimadzu MODEL 2600). - 100 -
3.7.4 ί ί (X-ray diffraction, XRD) Π,. - 0.1-100 Å,., ΠX. Π.,, ΠX, ΠX (diffraction pattern).., (l) XRD Scherrer: =. Ό : : 0.9, : Π, :, :. Π ( ) D8 ADVANCE (Bruker AXS Gmbh). - 101 -
3.7.5 ί ί ί ί ί ό ώ ί Π (X-ray Photoelectron Spectroscopy (XPS)). Π. Ό Π.. XPS 1-10 nm., : =., : h : Π : : XPS Π,. (Ultraviolet Photoelectron Spectroscopy (UPS)) XPS. -., µ. UPS UV - 102 -
(ionization cross-section),,. Π ( ) SPECS LHS-10. UPS HeI h = 21.22 ev (model UVS 10/35) Constant Retarding Ratio (CRR) mode CRR = 10. o -12.29 V, UPS. - 103 -
ί [1].,,,, 2009. [2] A. Berni, M. Mennig, H. Schmidt, Sol-Gel Technologies for Glass Producers and Users, Chapter Doctor Blade, pp 89-92, M.A. Aegerter et al. (eds.), Springer Science+Business Media, New York, 2004. [3] N. Asim, S. Ahmadi, M. A. Alghoul, F. Y. Hammadi, K. Saeedfar and K. Sopian, Review Article: Research and Development Aspects on Chemical Preparation Techniques of Photoanodes for Dye Sensitized Solar Cells, International Journal of Photoenergy, 2014, Article ID: 518156, 21 pages, http://dx.doi.org/10.1155/2014/518156 [4] C. D. Lokhande, Review: Chemical deposition of metal chalcogenide thin films, Mater. Chem. Phys., 1991, 27, 1 43. [5] P. K. Nair, M.T.S. Nair, V. Μ. Ζζχθı ζ, O. L. Arenas, Y. Peña, A. Castillo, I.T. Ayala, O. Gomezdaza, A. Sánchez, J. Campos, H. Hu, R. Suárez, M. E. Rincón, Semiconductor thin films by chemical bath deposition for solar energy related applications, Solar Energy Materials and Solar Cells, 1998, 52 (3 4), 313 344. [6]. ά, ί ό ύ ώ ή ή, ή ή, ή ώ,. [7] S. Sfaelou, X. Zhuang, X. Feng and P. Lianos, Sulfur-doped porous carbon nanosheets as high performance electrocatalysts for PhotoFuelCells, RSC Adv., 2015, 5, 27953 27963. [8] G. Hodes, J. Manassen and D. Cahen, Electrocatalytic Electrodes for the Polysulfide Redox System, J. Electrochem. Soc., 1980, 127 (3), 544-549. [9]. ά, έ ή ή ό ή έ έ ό / έ ά, ή ή, ή ώ,. [ ]. ί, ί ή ή, ό ί ί,. - 104 -
[11] B. M. Weckhuysen, R. A. Schoonheydt, Recent progress in diffuse reflectance spectroscopy of supported metal oxide catalysts, Catalysis Today, 1999, 49, 441-451. - 105 -
έ - 106 -
ά 4 ί ί ή ή έ ά ώ ό ώ - 107 -
ή Ό,.., TiO2.,.,,.. X ό ώ 4.1.1 ό ό ί TiO2 TiO2. Ό,., TiO2 (sol-gel) Degussa P-25. sol-gel TiO2 4.1., 6.5 nm. 4.1. TiO2 20-30 nm. - 108 -
ή 4.1: ό SEM ό ί TiO2 έ ί ό ά ύ ή sol-gel) ή ά TiO2 ό ή Degussa P-25. TiO2 sol-gel TiO2 (TiO2(s-g)) TiO2 (TiO2(P-25)). 4.2 ( ). ( 1) ( 2) FTO 320 nm. TiO2(s-g) ( 3) 300 nm., ( 4) TiO2, 7.5 m.,. - 109 -
ή 4.2: ί SEM ί TiO2 ά ό έ ώ ί FTO. ώ ί ί ή : ί, ώ ί FTO, (3) ί ί ό ά sol-gel (TiO2(sg)), (4) ί ί ό ό ά ή ή Degussa P-25 (TiO2(P-25)). TiO2. 4.3 20-25 nm SEM. - 110 -
ή 4.3: ό EM ί TiO2 έ ί ό ά ύ ή sol-gel) ή ά TiO2 ό ή Degussa P-25. 4.1.2 ό ό ύ ό Ό, TiO2 Silar,. CdS, Silar 3 Cd 2+., Cd(NO3)2, CdSO4 Cd(CH3COO)2. Ό CdS Cd(NO3)2 ((CdSN)), SEM ( 4.4) TiO2 CdSN/TiO2., CdS. - 111 -
ή 4.4: ί SEM ί TiO2 ά έ ώ ί FTO ί TiO2 έ CdSN. (CdS/TiO2), Π SEM. 4.5 TEM HR-TEM. : 4.9±1.2 nm CdSN, 5.7±1.1 nm CdS CdSO4 (CdSS) 7.1±1.5 nm CdS Cd(CH3COO)2 (CdS ). 25. CdS [1]., EDX Π 4.1. CdSN (1.8%) CdS (7.4%). S, Cd Cd 2+ - 112 -
ή 4.5: ό HR-TEM: (a) ί TiO2 ί TiO2 έ CdS Cd 2+ : (b) Cd(NO3)2, (c) CdSO4 ι Βι θ 2. ί 4.1: ό ό ί ύ έ EDX ά ί CdS/TiO2. ό ό % ό έ Cd 2+ O * Ti Cd S Cd(NO3)2 59.3 36.8 1.8 2.1 CdSO4 64.2 27.2 3.0 5.6 Cd(CH3COO)2 57.0 26.2 7.4 9.4 * ό ά ό ά ό ό /Ti ά ί ό ί. - 113 -
S 2- Silar.,,. Έ CdS CdS ph [2]. (pzc), 6.0±0.2 [3].., ph Cd(NO3)2 5.7 Cd(CH3COO)2 6.9 CdSO4 4.0.,, ph. Cd 2+,. Φ. Έ ZnS/CdSe/CdS /TiO2., SEM ( 4.6), TiO2. Ό CdS, 5 nm. - 114 -
ή 4.6: ό SEM ά : A) ί TiO2 (B) ί TiO2 έ CdSN, CdSe ZnS (ZnS/CdSe/CdS /TiO2). 4.1.3 έ ί TiO2 ί ί Π. 4.7 XRD FTO sol-gel Degussa P-25. TiO2 550 C,. TiO2(s-g) TiO2(P-25) 70/30 Degussa P-25. FTO., Scherrer TiO2 TiO2(s-g) 10 nm TiO2(P-25) 28 nm. - 115 -
ή 4.7: ά XRD ί ί ί έ ί ά ό FTO ό ή sol-gel ά ή ά ό Degussa P-25 ά. - 116 -
4.1.4 έ ό ί ά ά ύ- ώ UV-Vis DRS) -. DRS TiO2. Ό CdS/TiO2, CdS, Cd 2+ Silar. [4,5]. - TiO2 CdS 4.8.,, TiO2 CdS. Ό CdS Cd 2+, CdS TiO2. Ά, CdS. DRS., CdSN CdS. CdSS, CdSN CdS. - 117 -
ή 4.8: ά ά ά ύ- ώ έ TiO2 έ TiO2 έ CdS Cd 2+ : Cd(NO3)2, CdSO4 Βι θ 2. DRS TiO2 CdSN ZnS, Silar. Ό 4.9, TiO2 ZnS/TiO2,. ZnS CdSN,., CdSN/TiO2,.,. TiO2. - 118 -
( G), ( g) : ev = nm. Έ, CdS /TiO2 2.51 ev CdS -ZnS, ZnS., ZnS (25%)-CdS (75%) 2.58 ev, - (ZnS (50%)-CdS (50%)) 2.64 ev ZnS (75%)-CdS (25%) 2.67 ev. ή 4.9: ά ά ά ί TiO2 ό ώ ά CdS -ZnS. ύ ύ ά ά Cd Zn ό ύ ά ή ά έ Silar: (1) TiO2, (2) ZnS (100%)/TiO2, (3) ZnS (75%)-CdS (25%)/TiO2, (4) ZnS (50%)-CdS (50%)/TiO2, (5) ZnS (25%)-CdS (75%)/TiO2, (6) CdS (100%)/TiO2 [6]. - 119 -
,, CdS. CdSe, ZnSe CdS /TiO2 4.10. 3 F (R) 2 1 3 4 5 1 2 0 400 450 500 550 600 650 Wavelength (nm) ή 4.10: ά ά ά ί CdSN/TiO2 ό ώ ώ ά CdSe-ZnSe: (1) CdSN/TiO2, (2) 100% ZnSe/ CdSN/TiO2, (3) 50% ZnSe-50% CdSe/CdSN/TiO2, (4) 30% ZnSe-70% CdSe /CdSN/TiO2 (5) 100% CdSe/CdSN/TiO2. - 120 -
ZnSe Eg=2.7 ev, CdS (Eg=2.5 ev )., CdSe, 610 nm. CdSe ZnSe CdS /TiO2, ZnSe, [7]. PbS Sb2S3. TiO2 PbS, ( 4.11), 800 nm PbS. ή 4.11: ά ά ά ί TiO2 έ ά ί ώ ώ (PbS, PbS/CdS, CdS, CdSe ZnSe). - 121 -
TiO2 Sb2S3. Sb2S3 (Eg=1.7 ev ), 4.12 610 nm. ή 4.12: ά ά ά ί TiO2 ί TiO2 έ Sb2S3. 4.1.5 ή έ ί CdS/TiO2 UPS TiO2 CdS Cd 2+, UPS. TiO2 CdS/TiO2 4.13. (IP) ( - 122 -
). 2,. ( Fermi) Fermi. ( ),... Π 4.2. TiO2 7.4 ev CdSN CdSS (6.6 ev 6.7 ev)., CdS (5.7 ev). ή 4.13: ά UPS ί : (a) TiO2 ί TiO2 έ CdS ή ώ ό ώ : (b) CdSN/TiO2, (c) CdSS/TiO2, (d) CdSA/TiO2. - 123 -
ί 4.2: έ ύ ύ I.P. ί έ TiO2 ή ί έ CdS. ά I.P. (ev) TiO2 7.4 CdSN/TiO2 (Cd(NO3)2) 6.7 CdSS/TiO2 (CdSO4) 6.6 CdSA/TiO2 (Cd(CH3COO2)) 5.7 4.2 ό ώ 4.2.1 ό ό ώ (Carbon Cloth, CC).,. SEM 4.14. Ό, 10 m.,,. Έ (Multi-walled carbon nanotubes, MWCNTs). NiO. SEM ( 4.15) MWCNTs,., - 124 -
. NiO. NiO 70 nm. SEM NiO CC. ή 4.14: ό SEM ό : A) Carbon Cloth (CC), (B) ί Pt έ CC CC ά ό ό ό ά ά Pt. - 125 -
ή 4.15: ό SEM ό : A) MWCNTs (B) NiO έ MWCNTs., (GMC-S-X). SEM 4.16. 200 nm m.,. SEM,. - 126 -
ή 4.16: ό a) SEM ό b ύ ά έ έ έ ί. 4.2.2 έ ή ά ώ ΖΜΒ-S-X GMC-S-X (X=700, 800 900 C) -., : 462 m 2 g -1 GMC-S-700, 530 m 2 g -1 GMC-S-800 642 m 2 g -1 GMC-S-900. X=700, 800 900. Π 4.3. - 127 -
ί 4.3: έ ό ύ ά έ έ έ ί. ί ή ά (SBET) /m 2 g -1 Ό ό (Vmicro) /cm 3 g -1 ή ά ό (Smicro) /m 2 g -1 ό ό ό (VTot) /cm 3 g -1 Μέ ά ό (Dav) /nm GMC-S-700 462 0.077 212 0.59 5.10 GMC-S-800 530 0.176 407 0.74 5.59 GMC-S-900 642 0.209 462 0.89 5.57 4.2.3 ή έ XPS GMC-S-X GMC-S-X XPS., 3 ( 4.17 ). S GMC-S700, GMC-S800 GMC- S900 7.11%, 5.02% 4.74%. 164.1 165.3 ev ( 4.17 ). 164.1 ev CΠSnΠC ( n= 1 2) 165.3 ev ΠC=SΠ. 168.8 ev (Π SOnΠ). - 128 -
ή 4.17: ά XPS GMC-S700, GMC-S800 GMC-S900. - 129 -
4.3 ά ά ό ί ί 4.3.1 έ ί ί ύ ή ό ή ύ ά,. glass frit.,.,, [8]. 4.18 TiO2 Pt/CC..,, JSC 1.0 ma/cm 2 VOC 1.2 V ( 1) 1.8 ma/cm 2 1.0 V ( 2). glass frit.,, [7,9]. - 130 -
ή 4.18: ά ύ - ά ί ί ύ ά ό ά ή ά: ά : nc-tio2/fto, ό : Pt/CC, ύ : a. (+5% EtOH). ί EtOH ί ό έ ό. 4.3.2 ί ί ό έ Ό,.,. - TiO2. 4.19.,. - 131 -
, (JSC: 0.61 ma/cm 2, VOC: 1.03 V EtOH JSC: 0.14 ma/cm 2, VOC: 0.84 V EtOH). ή 4.19: ά ύ - ά ί ί ό ά ί ί ό ή ά: ά : nc-tio2/fto, ό : Pt/CC, ύ : a. (+5% EtOH). D ί ή ό L ή ό ό. - 132 -
,.,.,. Έ / (Current doubling/multiplication effect) ( ) TiO2 - [10-12].,, - [13]. Ό (VOC),., TiO2,..,. ( ), - ( Ag/AgCl) ( 4.20). Π 4.4. Ό, 10% v/v.,. - 133 -
ή 4.20: ά ύ - ά ί ί ύ ί ή ί ά μ/ gcl) ό ή ό : Ά : nc-tio2/fto, ό : Pt/CC, ύ :. Na ά ά έ ό : % v/v, (2) 0.1% v/v, (3) 0.5% v/v, (4) 2.0% v/v, (5) 5% v/v, (6) 10% v/v, (7) 20% v/v. - 134 -
ί 4.4: ί έ έ ό έ ύ ύ ά ύ ώ ί ί. ό έ ό % v/v) JSC (ma/cm 2 ) VOC (Volts) 0.0 0.29 0.87 0.1 0.61 1.06 0.5 0.75 1.08 2.0 0.86 1.11 5.0 0.93 1.13 10 0.98 1.15 20 1.01 1.14 4.3.4 ί ί ύ ύ,.. Na2SO4, NaOH. Έ [14]., TiO2,. 4.21 (NaOH, LiOH, KOH, NH4OH), 3 ( Ag/AgCl) TiO2 Pt., ( - ) (Na +, Li +, K +, NH4 + ). - 135 -
ή 4.21: ά ύ - ά ύ ί ή ί ά μ/ μβρ ό ή ό : Ά : nc-tio2/fto, ό : ύ Pt, ύ :. ό ί : (1) Li +, (2) Na +, (3) K + (4) NH4 +. ί έ ί έ ά ό Angstroms. -. -1.5-1.0 V vs Ag/AgCl,. Ό,. Ό,., - 136 -
TiO2., Li +, NH4 +. LiOH ( 4.22).. ή 4.22: ά ή ί ό ή ό ύ ώ ί ή ί ά Ag/AgCl: Ά : nc-tio2/fto, ό : ύ Pt, ύ :. Li. - 137 -
,, -. LiOH 4.23., TiO2, ( 4.23a). Ό TiO2 ( 4.23b),,,. Έ, ph. (NaCl, NaClO4, Na2SO4, CH3COONa NaOH) ( 4.24). ph Π 4.5. ph,. NaOH. - 138 -
ή 4.23: ά ύ - ά ό ή ό ύ ώ ί ώ ά nc-tio2/fto ό ύ Pt: (a) ά ώ LiOH ή ύ : (1) 0.05 M, (2) 0.2 M 0.5 M (b) ά ά ί TiO2: (1) 0.35 m, (2) 1.5 m, (3) 5 m (4) 10 m. - 139 -
ί 4.5: ύ ά ί ή ύ έ ί ph ό ό ό TiO2 ί έ ph. Η (C= 0.2 M) ph NaCl 6.1 NaClO4 6.2 Na2SO4 7.1 CH3COONa 8.5 NaOH 13.2 ή 4.24: ά ύ - ά ό ή ό ύ ώ ί ώ ά nc-tio2/fto, ό ύ Pt ά ά ύ Na + ύ : NaCl, (2) NaClO4, (3) Na2SO4, (4) CH3COONa (5) NaOH. έ ύ ά ί ή.. - 140 -
, TiO2. LiOH (0, 0.1, 1.0 5.0 v.% EtOH). 4.25a -., 5% v/v EtOH.,. ( 4.25b),,, [15]. - 141 -
ή 4.25: ά ύ - ά ί ί a) ό ή ό (b) ό ό ύ ώ ί nc-tio2/fto ά, ύ Pt ό,. LiOH ύ ά ά ό : v/v%, (2) 0.1 v/v%, (3) 1 v/v% v/v%. - 142 -
4.4 ί TiO2 έ ί.,. TiO2 [16]. Έ CdS. TiO2, CdS [17,18]. Ό, CdS Silar Cd 2+ (Cd(NO3)2, CdSO4 Cd(CH3COO)2) Silar, [19,20]. CdS/TiO2, CdS, Cd 2+. CdS CdS TiO2,. - ( 4.26), CdSA/TiO2,, CdS /TiO2. - 143 -
A B ή 4.26: A. ά ύ - ά ί ί ή ά: ά : nc-tio2, (2) CdSA/ nc-tio2, (3) CdSS/ nc-tio2, (4) CdSN/ nc-tio2, ό : Pt/CC, ύ : 0.5 M NaOH + 5% v/v EtOH. B. ά ά ά ί TiO2 ί TiO2 έ CdS ώ ά ό ά Cd 2+ (N: nitrate, S: sulfate, A: acetate). - 144 -
,.. 4.27 TiO2 CdS,. UPS. Ό, CdS,.., -0.60 V vs SHE., CdS., HO. +1.19 V vs SHE ( ph=14). CdSN/TiO2 HO CdS /TiO2. CdSS, CdS. VOC,., Π 4.6., CdSN/TiO2., CdSN/TiO2, IPCE IPCE ( 4.28). - 145 -
ή 4.27: έ ώ έ ί nc-tio2 FTO ί CdS/nc-TiO2/FTO έ έ ή ώ ό ά Cd 2+ έ ά ή ύ ό ό ά. ά ά ώ ώ CdS ά ί ή έ ί ό ά DRS. ό VB ή έ IP ί 4.2 ώ. ev ή SHE -0.83 V ph=14 (-0.059x14). ί 4.6: έ ύ ύ, ά ύ ώ ά ή ό έ TiO2 ή ί ή CdS. JSC (ma/cm 2 ) VOC (Volts) F.F. ό % TiO2 0.4 0.90 0.48 0.2 ό ά Cd 2+ Cd(NO3)2 7.5 1.26 0.45 4.3 CdSO4 5.4 1.26 0.45 3.1 Cd(CH3COO)2 4.4 1.24 0.39 2.1-146 -
ή 4.28: ύ ά ά ά CdSN/TiO2 ό ή ί ύ IPCE) έ ά, Pt/CC ό ύ. NaOH+5% EtOH., CdS/TiO2, ( 4.29). CdS /TiO2 10. - 147 -
ή 4.29: ή ό ύ ά ό ό ί ί ή ά: ά : nc-tio2 έ CdS ώ ά ό ά ί : Cd(NO3)2, (2) Cd(SO4)2, (3) Cd(CH3COO)2 ( ό ή: cm 2 ), ό : Pt/CC, ύ :. NaOH + 5% v/v EtOH. CdS/TiO2 CdS-ZnS [21,22]. CdS, CdS. 4.30. ZnS/TiO2 UV. - 148 -
ή 4.30: ά ύ - ά ί ί ή ά: ά : έ TiO2 έ ί CdS -ZnS έ ί : (1) ZnS(100%)/TiO2, (2) ZnS(90%)-CdS (10%)/TiO2, (3) ZnS(75%)-CdS (25%)/TiO2, (4) ZnS(50%)-CdS (50%)/TiO2, (5) ZnS(25%)-CdS (75%)/TiO2, (6) CdS (100%)/TiO2, ό : Pt/CC, ύ : 0.5 M NaOH + 5% v/v EtOH., CdS (10%)., CdS ZnS (25%) CdS/TiO2. Ό, ZnS/TiO2. VOC, TiO2-149 -
. Ω,. Έ 30 min 4.31. ή. : έ ό ύ ύ ή ύ Cd ό ά ύ ZnS(25%)-CdS (75%)/TiO2 ί ί ή ά: ά : ZnS(25%)-CdS (75%)/TiO2, ό : Pt/CC, ύ : 0.5 NaOH + 5% v/v EtOH. ά ύ ί έ ύ ύ έ ά ό min) ώ ά ύ ά ό min ό ό. - 150 -
Cd 30-70%. JSC ZnS(25%)-CdS (75%)/TiO2. Έ 30 min,. 4.32 75% CdS-25% ZnS 100% CdS. CdS, TiO2. ή 4.32: ά ύ - ά ί ί ή ά: ά : ZnS(25%)-CdS (75%)/TiO2, CdS (100%)/TiO2, ό : Pt/CC, ύ : 0.5 NaOH + 5% v/v EtOH. - 151 -
Έ CdSe, Sb2S3 PbS CdS ZnS., DRS,.,.,. Ό 4.33,,. Ό ( 4.33 ), Fermi., ZnS/CdSe/CdS /TiO2 PbS Sb2S3. - 4.34., CdS ZnS,. ή 4.33: ά ί ά ά : έ ύ ύ έ έ ή. - 152 -
ή 4.34: ά ύ - ά ί ί ώ ά nc-tio2 έ ά ί ώ ώ : (1) PbS/TiO2, (2) Sb2S3/TiO2, (3) Sb2S3/75%CdS- 25%ZnS/TiO2, (4) CdSe/75%CdS-25%ZnS/TiO2 (5) 75%CdS-25%ZnS/ io2, ό Pt/CC ύ 0.5 NaOH + 5% EtOH., ZnSe CdS CdSe 4.35. ZnSe CdSe., CdS,. - 153 -
ή. : ά ύ - ά ί ί ώ ά nc-tio2 έ ά ί ώ ώ : (1) CdS /TiO2, (2) ZnSe/CdS /TiO2, (3) ZnSe(50%)-CdSe(50%)/CdS /TiO2, (4) CdSe/CdS /TiO2. A ό : Pt/CC ύ : 0.5 NaOH + 5% EtOH. - 154 -
4.5 Μ έ ώ ώ, Pt. Έ (MWCNTs). NiO Pt/CC NiO/CC. Ό ZnS(25%)-CdS(75%)/TiO2. 4.36 - Π 4.7 JSC VOC. Ό, CC. CC NiO., CC NiO. Pt/CC. NiO/MWCNTs [23]. - 155 -
ή 4.36: ά ύ - ά ί ί ά : ZnS(25%)-CdS(75%)/TiO2, : (1) CC, (2) NiO/CC, (3) MWCNTs, (4) NiO/MWCNTs (5) Pt/CC, ύ :. NaOH + 5% v/v EtOH. ί 4.7: έ ύ ύ, ά ύ ώ ό έ έ ύ, ά ή ό ί ί ά ZnS(25%)- CdS(75%)/TiO2 ά ί ί. ό JSC (ma/cm 2 ) VOC (Volts) Μέ ύ (mw/cm 2 ) F.F. n (%) CC 2.1 1.0 0.25 0.12 0.3 NiO/CC 3.6 1.2 0.91 0.21 1.2 MWCNTs 4.8 1.2 1.90 0.33 2.4 NiO/MWCNTs 4.9 1.3 2.55 0.40 3.3 Pt/CC 4.7 1.2 2.76 0.49 3.7-156 -
(CC, Pt/CC, MWCNTs),,, Ag/AgCl ( 4.37)., MWCNTs CC Pt/CC.. ή 4.37: ά ή ί ώ ό ί CC, Pt/CC MWCNTs, έ ύ ό ό έ ό Ag/AgCl ό ά. ύ ή. aoh ύ ά ή mv/s ό ώ. - 157 -
Έ (GMC-S-X). Pt/CC, 4.38.,. 0 0.1 V.,., onset 1.5 2.0 V 0 V. onset Pt/CC. Pt/CC GMC-S-X. GMC- S-X, GMC-S700. GMC-S700, TiO2 CdS /TiO2., Pt/CC. 4.39 : ( ) TiO2 NaOH ( EtOH), ( ) TiO2 NaOH EtOH (C) CdS /TiO2 NaOH EtOH., GMC-S700 Pt/CC. Ό,. Ω,, onset. - 158 -
ή 4.38: ά ή ί TiO2 ά ά ί ί : (1) Pt/CC, (2) GMC-S800, (3) GMC-S900 GMC-S700 ύ ώ o ί ή ί ό ό ά. ύ : 0.5 M NaOH. ή ί ύ ό ύ ά ώ ή ί έ ή ύ ά. - 159 -
, onset.,. ή 4.39: ά ή ί ώ ώ ό Οω/ΒΒ ΖΜΒ-S7 /ΒΒ έ ώ : ά : TiO2, ύ :. NaOH ί EtOH, ά : TiO2, ύ :. NaOH + 5% v/v EtOH C ά : CdS /TiO2, ύ :. NaOH + 5% v/v EtOH. - 160 -
, 2. Π 4.8 4.40. Pt/CC, 1 ma CdS 25 ma. GMC-S700/CC, Pt/CC 0.3 V., GMC-S700/CC Pt/CC [24]. ί 4.8: έ ύ ύ ά ύ ώ ύ ώ ή ά ή 4.40. Pt/CC GMC-S700/CC Isc (ma) Voc (Volts) Isc (ma) Voc (Volts) 1 1.0 1.0 1.0 0.7 2 3.1 1.2 3.6 0.9 3 24.0 1.2 22.7 1.0-161 -
ή 4.40: ά ύ - ά ί ί ώ ό Pt/CC GMC-S700/CC ή ά: ά : TiO2, ύ :. NaOH ί EtOH, ά : TiO2, ύ :. NaOH + 5% v/v EtOH ά : CdS/TiO2, ύ :. NaOH + 5% v/v EtOH. ό ή ό ί ή ό ώ 10 cm 2 (3 cm x 3.3 cm). - 162 -
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[10] P. Lianos, Production of Electricity and Hydrogen by Photocatalytic Degradation of Organic Wastes in a Photoelectrochemical Cell. The concept of the Photofuelcell: A Review of a Re-Emerging Research field, J. Hazard. Mater., 2011, 185, 575 590. [11] E. Kalamaras, P. Lianos, Current Doubling effect revisited: Current multiplication in a PhotoFuelCell, Journal of Electroanalytical Chemistry, 2015, 751(15), 37 42. [12] S. Karuppuchamy, M. Iwasaki, H. Minoura, Electrochemical Properties of Electrosynthesized TiO2 Thin Films, Appl. Surf. Sci., 2006, 253, 2924 2929. [13] R. Michal, S. Sfaelou, P. Lianos, Photocatalysis for Renewable Energy Production Using PhotoFuelCells, Molecules, 2014, 19, 19732 19750. [14] S. Kambe, S. Nakade, T. Kitamura, Y. Wada and S. Yanagida, Influence of the Electrolytes on Electron Transport in Mesoporous TiO2 Electrolyte Systems, J. Phys. Chem. B, 2002, 106 (11), 2967 2972. [15] L.-C. Pop, S. Sfaelou, P. Lianos, Cation adsorption by mesoporous titania photoanodes and its effect on the current-voltage characteristics of photoelectrochemical cells, Electrochimica Acta, 2015, 156, 223 227. [16] P. V. Kamat, Quantum Dot Solar Cells. Semiconductor Nanocrystals as Light Harvesters, J. Phys. Chem. C, 2008, 112 (48), 18737-18753. [17] R. Nakamura, S. Makuta and Y. Tachibana, Electron Injection Dynamics at the SILAR Deposited CdS Quantum Dot/TiO2 Interface, J. Phys. Chem. C, 2015, 119 (35), 20357 20362. [18] M. Antoniadou, D. I. Kondarides, D. D. Dionysiou, and P. Lianos, Quantum Dot Sensitized Titania Applicable as Photoanode in Photoactivated Fuel Cells, J. Phys. Chem. C, 2012, 116, 16901-16909. [19] R. Zhou, Q. Zhang, J. Tian, D. Myers, M. Yin, G. Cao, Influence of Cationic Precursors on CdS Quantum-Dot-Sensitized Solar Cell Prepared by Successive Ionic Layer Adsorption and Reaction, J. Phys. Chem. C,,,. [20] K. C. Preetha, K. V. Murali, A. J. Ragina, K. Deepa, A. C. Dhanya, T. L. Remadevi, The role of Cationic Precursors in Structural, Morphological and Optical Properties of PbS Thin Films, IOP Conf. Ser.: Mater. Sci. Eng., 2013, 43, 012009, doi:10.1088/1757-899x/43/1/012009. - 164 -
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ά 5 ί ί ή έ ά ό ό ώ - 166 -
ή,, [1].,, S/Na2S Na2S/Na2SO3., 2, S/Na2S S2 2-., Na2S/Na2SO3. Ω TiO2, (CuS, CoS, Cu2S) ο.. ό ί ό.. ό ί ά ά (DRS)., TiO2 (CdS/TiO2,CdSe/CdS/TiO2, ZnS/CdSe/CdS/TiO2). [2]., - 167 -
400 C. 5.1. CdS Silar Cd(NO3)2. CdS /TiO2,., CdSe/CdS /TiO2. CdSe, [2]. ZnS/CdSe/CdS /TiO2. ή 5.1: ά ά ά ί CdS/TiO2, CdSe/CdS/TiO2 ZnS/CdSe/CdS/TiO2: ί έ, ό έ C ό ό ή ό έ C ί N2. ό ό ά ή ύ ί ί ά. - 168 -
Ό, TiO2 CdS CdS Silar., CdSA/TiO2 PbS. 5.2a CdS/TiO2, CdSA/PbS/TiO2 5.2b. PbS/TiO2 800 nm PbS.,., CdS PbS/TiO2 CdS PbS [3,4]., DRS, (CdS /PbS/TiO2) PbS,.,,. - 169 -
ή 5.2: ά ά ά (a) ί CdS/TiO2 έ ύ ή ώ ό ώ Cd 2+ : (1) Cd(NO3)2, (2) CdSO4, (3) Cd(CH3COO)2 (b) ί : (1) PbS/TiO2, (2) CdSA/PbS/TiO2. - 170 -
5.1.2 ό ί Raman TiO2 (CdS /TiO2, CdSe/CdS /TiO2, ZnS/CdSe/CdS /TiO2), Raman Micro-Raman. Ό Raman, 5.3. Ω TiO2., 143 cm -1. CdSN, CdS 302.5 cm -1. CdSe, CdS. Ό, CdSe CdSxSe1-x CdSN CdSe., ZnS., Micro-Raman 5.4. CdSN/TiO2, CdS,. CdS [5]., Silar,, [6]. CdSe, ZnS [7], 20. - 171 -
ZnS. ή 5.3: ά Raman ί TiO2 ά ά ί ή ώ ώ. - 172 -
ή 5.4: ά Micro-Raman ί TiO2 ά ά ί ή ώ ώ, ύ ό ό.. ό ώ 5.2.1 ό ό ώ (CuS, CoS) FTO Cu2S. CoS FTO.,. 5.5. Ό CuS/FTO, SEM 5.5. - 173 -
CoS. ή 5.5: ό SEM ό ί CoS/FTO ( ά ό CuS/FTO ά ό. ί ί m nm ί. - 174 -
Cu2S,. [8,9]. Ό SEM Cu2S ( 5.6),., Π. EDX ( 5.7) S/Cu ½. - 175 -
ή 5.6: ό SEM ( ό Cu2S ό ύ ί ί (a) m (b) 200 nm. ή 5.7: ά EDX ό ό ί ό ό S/Cu ί έ ί 36/65. - 176 -
5.2.2 ό Cu2S ί ί Cu2S,, XRD. 5.8 Cu Cu2S S. intensity (a.u.) Cu Cu 2 S Cu 40 45 50 55 60 degree ή 5.8: ά XRD Cu2S ό ή ί ύ ί. 5.3 ί ό έ ύ ΒιΣ έ ΒιΣ/ΤξO2 Ό, CdS TiO2 Silar, Cd 2+ (Cd(NO3)2, CdSO4 Cd(CH3COO)2). 5.9 Π 5.1, - 177 -
. Ό, TiO2. CdS,. Έ, CdS. ( 5.10).,.,. [10]. ή 5.9: ά ύ - ά ί ί ή ά: ά : nc-tio2, (2) CdSN/ nc-tio2, (3) CdSS/ nc- TiO2, (4) CdSA/ nc-tio2, ό : Cu2S, ύ : 1.0 M Na2S/1.0 M S. - 178 -
ί. : έ ύ ύ, ά ύ ώ, ά ή ό ό ώ ύ ή 5.9. JSC (ma/cm 2 ) VOC (Volts) F.F. ό % TiO2 0.2 0.22 0.42 0.02 ό ά Cd 2+ Cd(NO3)2 5.4 0.55 0.47 1.4 CdSO4 5.9 0.56 0.54 1.8 Cd(CH3COO)2 6.6 0.58 0.58 2.2 ή 5.10: έ ώ έ ί nc-tio2 FTO ί CdS/nc-TiO2/FTO έ έ ή ώ ό ά Cd 2+ έ ά ή ύ, ό ύ ύ ό ά. - 179 -
-, (IPCE%) CdSA/TiO2. DRS 5.11.,. ή 5.11: ύ ά ά ά CdS /TiO2 ό ή ί ύ IPCE ύ έ ά, Cu2S ό ό ύ. - 180 -
5.4 Μ έ ώ ώ ώ έ TiO2.. έ ZnS/CdSe/CdS/TiO2 ά ά ί TiO2 [11].,,,. Έ, (.. CdSe, PbS, ZnSe). Έ, CdS, CdSe ZnS [12]. TiO2 (CdS/TiO2,CdSe/CdS/TiO2, ZnS/CdSe/CdS/TiO2) - 5.12., 5.11 Π 5.2. TiO2,, UV. Έ, ZnS/CdSe/CdS/TiO2, ZnS, (2 Silar). (0.53Π0.59 V),, TiO2. - 181 -
TiO2, (0.38 V) Φ [13]. ή 5.12: ά ύ - ά ί ή ά: ά : ΤξO2/FTO, (2) CdS/TiO2/FTO, (3) CdSe/CdS/TiO2/ΕΤO ZσΣ/ΒιΣκ/ΒιΣ/ΤξO2/ΕΤO, ό : Cu2S/ ί, ύ : 1 M Na2S/1 M S. ά ά έ ό ύ ά ά -1). - 182 -
ί 5.2: έ ύ ύ, ά ύ ώ, ά ή ό ό ώ ύ ή 5.11. JSC VOC ό ά (ma/cm 2 ) (Volts) F.F. (%) TiO2/FTO 0.9 0.38 0.32 0.1 CdS/TiO2/FTO 8.0 0.53 0.44 1.9 CdSe/CdS/TiO2/FTO 11.7 0.54 0.43 2.7 ZnS/CdSe/CdS/TiO2/FTO 12.9 0.59 0.37 2.8 ZnS/CdSe/CdS/TiO2 IPCE. 5.13, IPCE. - 183 -
ή 5.13: ύ ά ά ά ί ZnS/CdSe/CdS/TiO2 ό ή ί ύ IPCE) ύ έ ά, Cu2S ό ό ύ., ( 5.14). Raman. TiO2. (ZnS/CdSe/CdS/TiO2)., ZnS,, CdS/TiO2. Ό, ZnS - 184 -
(CdS CdSe)., Η Θ /, [7]. 12 4 J sc (ma cm -2 ) 10 8 6 4 3 2 2 0 0 50 100 150 200 1 Time (min) ή 5.14: ί ό ό ή ύ ύ ύ ή ά: ά : TiO2/FTO, (2) CdS/TiO2/FTO, (3) CdSe/CdS/TiO2/ΕΤO ZnS/CdSe/CdS/TiO2/ΕΤO, ό : Cu2S/ ί, ύ : 1 M Na2S/1 M S. - 185 -
5.4.2 ί έ ό ώ Ό, [3]., TiO2,. - 5.15. CdS/TiO2,,.,.., CdSe/CdS/TiO2 ZnS/CdSe/CdS/TiO2., CdSe/CdS/TiO2, 300 C 400 C. Ό,, [2]., CdSxSe1 x Raman VOC. ZnS/CdSe/CdS/TiO2. 100 C. [14]. - 186 -
ή 5.15: ά ύ - ά ί ή ά: ά : a) CdS/TiO2, (b) CdSe/CdS/TiO2 (c) ZnS/CdSe/CdS/TiO2 έ ί ί ώ ί : (1) 100 C, (2) 200 C, (3) 300 C, (4) 400 C, ό : Cu2S/ ί, ύ : 1 M Na2S/1 M S., ( 5.16). CdS/TiO2, -,., Φ 100 C.,., - 187 -
., ZnS [14]. ή 5.16: ύ ύ ύ ά ό ό ά ή ά: ά : a) CdS/TiO2, (b) CdSe/CdS/TiO2 c) ZnS/CdSe/CdS/TiO2 ί : (1) έ ί έ, (2) 400 C έ έ, C έ ά, ό : Cu2S/ ί, ύ : M Na2S/1 M S. - 188 -
CdS PbS. Ό, PbS 850 nm,., PbS,., CdS PbS TiO2. CdS PbS /, CdSA [3,15,16]. 5.17 - (PbS/TiO2 CdS /TiO2) PbS CdS. PbS/TiO2,. CdS TiO2 PbS/TiO2. CdS /TiO2 5 Silar CdS. CdS /PbS/TiO2 15 ma/cm 2.,, 5.18. - 189 -
ή 5.17: ά ύ - ά ί ή ά: ά : PbS/TiO2 (2 ύ Silar), (2) CdS /TiO2 (5 ύ Silar), (3) CdS /PbS/TiO2, ό : Cu2S/ ί, ύ : M Na2S/1 M S. ή 5.18: ά ί (a ί PbS ά TiO2 b ά ό CdS /PbS/TiO2. ή ί ί ph 13.0 (-0.77 vs SHE). - 190 -
, CdSA PbS 5.19. PbS/TiO2 80% CdSA 25%. ή 5.19: ύ ό ύ ά ό ό ά ή ά: ά cm 2 ): (1) PbS/TiO2, (2) CdS /PbS/TiO2, ό : Cu2S/ ί, ύ : M Na2S/1 M S. - 191 -
. Μ έ ώ ώ, Cu2S., CoS/FTO CuS/FTO,.,. Cu2S, Cu2S. Π 5.3 (RS) / (RCT) 5.20 Nyquist Cu2S.,,., RCT 1153 Cu2S 2.3. Cu2S. Ό CoS/FTO CuS/FTO, RS RCT Cu2S/. - 192 -
ί 5.3: έ ή έ ή ά ί ί. ό Rs (Ohm) Rct (Ohm) ί 4.8 1153 Cu2S/ ί 5.3 2.3 CoS/FTO [17] 18 48 CuS/FTO [17] 19 6 RS: ω ή α ί α η RCT: α ί α η α ά ί η ά α η ί /η ύ η ή 5.20: ά ί ή έ ό ί ύ ό ύ ί ή ή (2) ό ή ί ό Cu2S ό ύ. έ ά ί έ έ έ ί. - 193 -
/ Cu2S/.., (+1.5 V -1.5 V) Pt. 5.21 (0.01 Na2S/0.01 S 1.0 Na2S/1.0 S). Ό, -0.41 V -0.94 V. Cu2S.,. -0.65 V ( ) Cu2S. - 194 -
ή 5.21: ά ή ί ί ώ ό ί Cu2S/ ί, ό έ ύ Pt έ ό Ag/AgCl ό ά. ύ ή ά ί ή :. Νζ2Σ/. Σ (2). Νζ2Σ/. Σ., ZnS/CdSe/CdS/TiO2. 5.22, Π 5.4... CuS/FTO (3.5%).,, Cu2S. - 195 -
ή 5.22: ά ύ - ά ί ή ά: ά : ZnS/CdSe/CdS/TiO2, ό : (1) CuS/FTO, (2)CoS/FTO (3) Cu2S/ ί, ύ : 1 M Na2S/1 M S. ί 5.4: έ ύ ύ, ά ύ ώ, ά ή ό ό ώ ύ ή 5.21. ά ό J (ma/cm 2 ) V (Volts) FF (%) ZnS/CdSe/CdS/TiO2 CuS/FTO 17.1 0.56 0.36 3.5 ZnS/CdSe/CdS/TiO2 CoS/FTO 17.4 0.54 0.32 3.0 ZnS/CdSe/CdS/TiO2 Cu2S/brass 13.3 0.51 0.39 2.6-196 -
Na2S/Na2SO3. Ω TiO2, Pt/CC Cu2S/.. 5.23. Ό,. ZnS/CdSe/CdSN/TiO2. Current Density (ma/cm 2 ) 8 6 4 2 0 2A 2B 3B 3A 1A 1B -1,5-1,0-0,5 0,0 0,5 1,0 V (Volts) vs. Ag/AgCl ή 5.23: ά ύ - ά ώ ύ ώ ί ή ί ά Ag/AgCl) ή ά: ά : TiO2, (2) CdSN/TiO2, (3) ZnS/CdSe/CdSN/TiO2, ό : Pt/CC, (B) Cu2S/ ί, ύ : 0.25 M Na2S/0.125 M Na2SO3. - 197 -
, Cu2S/ Pt/CC., [18,19]. Ά, Pt., TiO2. Π 5.5. Ό 0 V 0.5 V. Ό,., 0.5 V. ί 5.5: έ ό ή ό ώ έ ό, ό Cu2S/ ί ύ 0.25 M Na2S/0.125 M Na2SO3. ά ά ό ά (Volts) Μέ ό ή ό ( mol/min) nc-tio2/fto 0 0.001 0.5 0.2 CdS/nc-TiO2/FTO 0 0.05 0.5 0.5 ZnS/CdSe/CdS/nc-TiO2/FTO 0 0.2 0.5 3.2-198 -
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ά 6 ί ύ ή ή ό - 202 -
ή,, TiO2. WO3 BiVO4. WO3 n- 2.5-2.7 ev 500 nm., ph [1,2]. Ό BiVO4, ( 2.8 ev), [3,4]. ( WO3) TiO2. Ό, 2 2 (1.23 V vs. NHE ph=0) + 2 (0 V vs. NHE ph=0).,.. - 203 -
6.1 ό ώ ΧO3 ΑξΦO4 WO3 BiVO4. Ό SEM 6.1, WO3. 20 50 nm., BET 25.4 m 2 /g. TiO2 (Degussa P25) 45-50 m 2 /g. ή 6.1: ό SEM ά ί WO3 ή ά. - 204 -
Ό BiVO4,, Triton X-100. 6.2 SEM BiVO4 FTO 0.1 g/ml Triton X-100. 50 nm. ή 6.2: ό SEM ά ί BiVO4 ί ά ή. g/ml Triton X-100 ύ ό ά. Π. WO3, 6.3. FTO WO3 25 nm Scherrer. SEM. - 205 -
ή 6.3: ά ί ί ΧO3 έ ί FTO. XRD BiVO4 Triton X-100. sol-gel BiVO4. 6.4, Π 6.1. BiVO4, Triton X-100 Bi4V2O11. 0.1 g/ml Triton X-100,. - 206 -
ή. : ά XRD ί BiVO4 έ ί ή ώ ώ ύ Triton X-100 ό ά. έ έ ί X ύ ί ή ό ύ ό ύ ό ό Bi4V2O11., - Π 6.1., 3.4 16.5 m 2 /g TiO2 Degussa P-25 (45-50 m 2 /g).. Triton X-100 0.1 g/ml Triton X-100. - 207 -
ί. : ά ά BiVO4 ά ώ έ ώ ύ TritonX-100. έ Μέ SBET ά ά Ό Triton X-100 ί (m 2 /g) ό ό ό (g/ml) (nm) (nm) (nm) (cm 3 /g) 0.025 34.5 3.5 18.5 9.4 0.008 0.05 34.9 9.3 6.8 7.2 0.016 0.10 22.8 12.7 6.0 6.4 0.020 0.25 46.3 13.5 11.8 14.8 0.050 0.50 49.0 16.5 10.5 13.4 0.055,.,, Triton X-100 (0.025 g/ml)., 6.5. UV., WO3 465 nm, BiVO4 505 nm. - 208 -
ή 6.5: ά ά ά ί WO3 BiVO4 έ FTO. 6.2 έ ή ή ύ ό WO3,,.,. 6.6.,., 1.6 V - 209 -
vs Ag/AgCl ( onset 2.0 V vs Ag/AgCl) 3.5 ma/cm 2 6.3 ma/cm 2. ή 6.6: ά ύ - ά ί ί έ ά WO3, ό έ ύ Pt ύ. NaClO4 : ή ό ό ό : ί ό έ ί 5% v/v ό. Ό,, [5]. onset 0.3 V vs Ag/AgCl. onset -0.2 V vs Ag/AgCl, Na + - 210 -
,. NaClO4 LiClO4. Ό ( 6.7), LiClO4, Li + Na +, WO3 [6]. ή 6.7: ά ή ί ύ ώ ί ή Ag/AgCl ό ά ί έ ά WO3, ό έ ύ Pt ύ. NaClO4 ή. LiClO4. ύ ά έ ί ή ό. - 211 -
TiO2, - ( 4.5 mg/cm 2 ). ( 6.8). WO3.., TiO2, onset WO3. WO3 IPCE ( 6.9). ή 6.8: ά ύ - ά ύ ώ ί ή Ag/AgCl ό ά ί ί ή ά: ά :, WO3, TiO2, ό : ύ Pt, ύ :,. NaClO4,. NaClO4 + 5% v/v EtOH. - 212 -
ή 6.9: ά ά ά ύ WO3 έ IPCE%. έ IPCE ή ή ή ά 1.6 V vs Ag/AgCl., WO3. 1.0 V vs Ag/AgCl 1.6 V vs Ag/AgCl. 6.10. FTO. 5% v/v.,., 20 [7]. - 213 -
ή 6.10: ή ή ό mol/min) ή ή ό (mmol) ί έ ά WO3 ό ί FTO ί ί ί ή ά ά ί ύ. ά ό ά ί 1.0 V vs Ag/AgCl ή. V vs Ag/AgCl. - 214 -
BiVO4, (Triton X-100),., Triton X-100: 0.025, 0.05 0.1 g/ml. 6.11. ή 6.11: ά ύ - ά ύ ώ ί ή ί Ag/AgCl ό ά ί ί BiVO4 ά, έ ύ ύ ό. NaHCO3 ύ. ά έ ί ή ό ύ Triton X-100: ή ό, 0.025 g/ml, (3) 0.05 g/ml (4) 0.1 g/ml. Ό ά ά ά RHE έ ό έ ί ά ά ό έ : V(Volts) = 0.2+0.059x(pH), ό 0.2 ί ό Ag/AgCl vs. SHE ί ή ph ύ NaHCO3 ί.. - 215 -