CdSe nanoparticles with well-defined crystallinity were assembled into vertically aligned TiO2 nanotube arrays (TiO2 NTAs) by cyclic voltammetry electrochemical deposition with an aim to tune the response of photoelectrochemical cell in visible region. Through this method, CdSe nanocrystals were deposited into intra- and inter-tubular space of the TiO2 nanotubes (TNTs) to form three-dimensional (3D) multijunction structure. The amount of SeO2 added during electrodeposition of CdSe played an important role in formation of the heterostructures. A maximum short-circuit photocurrent of 7.72 mA/cm(2) and open circuit potential of 1.24 V were achieved under visible light illumination. The remarkable photoresponse should ascribe to the high-quality of 3D multijunction structure. Such heterostructure system would serve as a promising candidate for solar energy conversion. (C) 2013 Elsevier Ltd. All rights reserved.