The novel photoelectrochemical cell with very high photocurrent density (>35 mA/cm(2)) is demonstrated by nanoscale architecturing of TiO2/CdS/CdSe multi-core-shell nanorods. While dimensions of constituting layers, i.e. TiO2 nanorod templates, CdS, and CdSe shell layers, are optimized by thorough investigation of optical and photoelectrochemical responses of each layer, high light absorption through the nanorod geometry and facile transport of the photo-generated electrons and holes along the high conduction path of CdSe and CdS result in the high photoelectrochemical performances. In addition, the microscopic model for the electron and hole transport in the core-shell nanorod is elaborated using the energy band diagram. The demonstration of the high performance PEC electrode as well as the platform to optimize PEC electrodes are highlighted in the current work. (C) 2018 Elsevier Ltd. All rights reserved.