용액공정이 가능한 5 nm 정도의 입경을 가지는 이산화티탄 단분산 나노졸을 솔-젤법을 통하여 합성하였다. 결정성 이산화티탄 나노졸의 저온 스핀코팅 공정을 통하여, 거친 표면을 가지는 FTO 투명전극 기판에 블록킹층을 형성하였다. 이산화티탄 나노졸을 블록킹층에 코팅을 함으로써 거친 FTO 표면을 점진적으로 완만하게 할 수 있었다. 1, 2.5, 5, 및 10 중량%의 결정성 이산화티탄 나노 졸을 FTO 투명전극 기판에 스핀코팅하여 29, 38, 62 및 226 nm 두께의 이산화티탄 블록킹층을 형성할 수 있었다. 5 및 10 중량%의 결정성 이산화티탄 나노 졸의 경우 제곱평균 48.7 nm의 표면조도를 가지는 FTO의 투명전극 표면을 효과적으로 평탄화할 수 있었으며 이로 인해 1차원 형태의 산화아연 나노막대를 효과적으로 기판에 수직으로 배향할 수 있었다.

We synthesized the solution processible monodispersed TiO2 crystalline nano-sol with ~ 5 nm in size by sol-gel method. Through the spin-coating of crystalline TiO2 nano-sol at low processing temperature, we could make even blocking interlayer on the rough FTO transparent electrode substrate. The rough FTO surface could be gradually smoothed by the spin-coating of nano-crystalline TiO2 sol based blocking interlayer. The 1, 2.5, 5, and 10 wt% of nanocrystalline TiO2 sol formed 29, 38, 62, and 226 nm-thick of blocking interlayer in present experimental condition,_x000D_ respectively. The 5 and 10 wt% of TiO2 nano-sol could effectively fill up the valley part of bare FTO with 48.7 nm of rms (root mean square) roughness and consequently enabled the ZnO to be grown to vertically aligned one dimensional nanorods on the flattened blocking interlayer/FTO substrate.

TiO2 Nano-sol ZnO Nanorods Surface Roughness Vertical Alignment Photoanode

Yang P, Yan R, Fardy M, Nano Lett., 10, 1529 (2010)
Hu J, Odom TW, Lieber CM, Acc. Chem. Res., 32, 435 (1999)
Xia YN, Yang PD, Sun YG, Wu YY, Mayers B, Gates B, Yin YD, Kim F, Yan YQ, Adv. Mater., 15(5), 353 (2003)
Qu J, Li G, Gao X, Energy Environ. Sci., 3, 2003 (2010)
Sreekumarana Nair A, Energy Environ. Sci., 3, 2010 (2010)
Lee YH, Heo JH, Im SH, Kim Hj, Lim CS, Ahn TK, Seok SI, Chem. Phys. Lett., 573, 63 (2013)
Yi GC, Wang C, Park WI, Semicond. Sci. Technol., 20, S22 (2005)
Wagner R, Ellis W, Appl. Phys. Lett., 4, 89 (1964)
Yamai I, Saito H, J. Cryst. Growth., 45, 511 (1978)
Law M, Greene LE, Johnson JC, Saykally R, Yang PD, Nat. Mater., 4(6), 455 (2005)
Yodyingyong S, Zhou X, Zhang Q, Triampo D, Xi J, Park K, Limketkai B, Cao G, J. Phys. Chem. C., 114, 21851 (2010)
Breckenridge RG, Hosler WR, Phys. Rev., 91, 793 (1953)
Forro L, Chauvet O, Emin D, Zuppiroli L, Berger H, Levy F, J. Appl. Phys., 75, 633 (1994)
Duzhko V, Timoshenko VY, Koch F, Dittrich T, Phys. Rev. B., 64, 075204 (2001)
Greene LE, Law M, Yuhas BD, Yang P, J. Phys. Chem. C., 111, 18451 (2007)
Heo JH, Im SH, Kim HJ, Boix PP, Lee SJ, Seok SI, Mora-Sero I, Bisquert J, J. Phys. Chem.C., 116, 20717 (2012)
Im SH, Kim HJ, Rhee JH, Lim CS, Seok SI, Energy Environ. Sci., 4, 2799 (2011)
Lim CS, Im SH, Rhee JH, Lee YH, Kim HJ, Maiti N, Kang Y, Chang JA, Nazeeruddin MK, Gratzel M, J. Mater. Chem., 22, 1107 (2012)
Greene LE, Law M, Tan DH, Montano M, Goldberger J, Somorjai G, Yang P, Nano Lett., 5, 1231 (2005)
Im SH, Lee SH, Hong YJ, Choi WY, “Titania Sol, Method of Preparing The Same, and Coating Composition Comprsing The Same,” WO Patent 2,007,073,043 (2007)
Chang JA, Rhee JH, Im SH, Lee YH, Kim HJ, Seok SI, Nazeeruddin MK, Gratzel M, Nano Lett., 10, 2609 (2010)
Im SH, Lim CS, Chang JA, Lee YH, Maiti N, Kim HJ, Nazeeruddin MK, Gratzel M, Seok SI, Nano Lett., 11, 4789 (2011)
Chang JA, Im SH, Lee YH, Kim HJ, Lim CS, Heo JH, Seok SI, Nano Lett., 12, 1863 (2012)
Kim H, Jo Y, Lee K, Lee I, Tak Y, Korean Chem. Eng. Res., 50(1), 162 (2012)
Chae YK, Park JW, Mori S, Suzuki M, Korean J. Chem. Eng., 30(1), 62 (2013)
Xiong L, Zhong Q, Chen Q, Zhang S, Korean J. Chem. Eng., 30(4), 836 (2013)