CdS or CdSe Decorated TiO CdS or CdSe Decorated TiO 2 Nanotube CdS - PowerPoint PPT Presentation

KOREA-USA Nanoforum CdS or CdSe Decorated TiO CdS or CdSe Decorated TiO 2 Nanotube CdS or CdSe Decorated TiO CdS or CdSe Decorated TiO 2 Nanotube Nanotube Nanotube Arrays from Spray Arrays from Spray Pyrrolysis Pyrrolysis Deposition: Deposition: U Use in Photoelectrochemical Cells Use in Photoelectrochemical Cells U i i Ph Ph l l h h i i l C ll l C ll Sungkyunkwan Sungkyunkwan University University Jong Jong Hyeok Hyeok Park Park

Solar Resource Solar Resource Additional Energy about 30 TW 165,000 TW of Sunlight hit the earth should be produced until 2050 h ld b d d til 2050 One of Possible Strategies: Solar Energy Solar Energy

Energy Conversion Strategies Energy Conversion Strategies Energy Conversion Strategies Energy Conversion Strategies Energy Conversion Strategies Energy Conversion Strategies Fuel Fuel Light Light Electricity Electricity Electricity Electricity Fuels Fuels Electricity Electricity CO 2 CO 2 CO 2 CO 2 O O O 2 O 2 H H H 2 H 2 e e e e Sugar Sugar M M SC SC M M SC SC H 2 O H 2 O H 2 O H 2 O O 2 O 2 Semiconductor / Liquid Semiconductor / Liquid Photosynthesis Photosynthesis Photosynthesis Photosynthesis Photovoltaics Photovoltaics Photovoltaics Photovoltaics Junctions Junctions

Nanostructured Nanostructured Materials Materials Appl. Phys. Lett. 89, 163106 (2006) Nano Lett. 6, 24 (2006). Chem. Comm. 2867 (2008). J. Mater. Chem. 20, 2247 (2010). Chem. Comm. 2385 (2010). ACS Appl. Mater. & Inter. 2, 288 (2010).

In My Poster: In My Poster: QDs QDs Coated TiO Coated TiO 2 NTs NTs CdS or CdSe precursor solution CdS or CdSe TiO 2 NT Ti foil Hot Plate (~450 o C) Spray Pyrolysis Method: 1. Simple 2. Suitable for large area coating 3. Precursor solution spray during thermal annealing of substrates

Analysis of Mechanism: Analysis of Mechanism: High Current Density High Current Density 11 ⊖ ⊖ ⊖ 3 μ mTiO 2 NTs 10 ⊖ CdSe/3 μ m m2 ) 9 CdS/0.4 μ m rrent ( mA/cm � � � � � � CdSe/0.4 μ m CdSe/0 4 μ m 8 Q.D 7 TiO 2 NT 6 5 ⊖ ⊖ 4 Photocu ⊖ 3 � 2 Q.D Q 1 TiO NT TiO 2 NT 0 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 Aqueous solution: 0.35 M Na 2 SO 3 + 0.24 M Na 2 S. Potential (V) vs Ag/AgCl 10 8 cy (%) 6 Efficienc 4 2 η (%) = [J p × (1.23 – E app )]/P light ] ( ) [ ( )]/ ] 0 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 Potential (V vs. Ag/AgCl)

Length= 600nm Length=1500nm

CdS NPs coupled TiO CdS NPs coupled TiO 2 NRs NRs - - SPD SPD 0.1M thiourea 0.1M CdCl 2 CdS nanoparticle TiO 2 nanorod FTO glass Hot plate(450 ℃ )

CdS NPs coupled TiO CdS NPs coupled TiO 2 NRs NRs - - SPD SPD

Unassisted Water Splitting Unassisted Water Splitting Pt Dye-coated TiO 2 N-type SC N type SC I 3 - Dye e - h + e - h + e - e- e- I - I TiO 2 2H + + 2e - → H 2 N-type SC Ti-foil or SUS foil e - e h + h + H 2 O + 2h + → 2H + + 1/2O 2

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