Bottom-up strategies for the fabrication of nanomaterials have the advantage of scalability,cost-effective and sustainability,and thus hold great potential to solve the current critical energy and environmental issues facing humanity.Current challenges consist of assembly of the nanomaterials into,for example,various forms of films,which are immensely useful in realistic applications of the nanomaterials.The key is to understand the interplay between the material components.In this contribution,I will present some of our recent results in interfacing and assembling different nanostructures down to molecular levels by solution processes.The resulting architectures have been explored for the development of new generation energy conversion devices.In particular,three examples will be given including a new sensitized solar cell sensitized by a solution processed quasi-quantum well(QW)structure and a three dimensional(3D)scaffolded pseudocapacitor.The QW structure of ZnSe/CdSe/ZnSe)was quasi-epitaxially deposited on ZnO tetrapods.Such a novel photoanode architecture has attained 6.20%PCE,among the highest reported to date for this type of solar cells.Carrier dynamic studies support a core-shell two-channel transport mechanism and suggest that the electron transport along sensitizer can be considerably accelerated by the QW structure we employed.The 3D scaffolded pseudocapacitor is based on highly conductive NiCo2S4 single crystalline nanotube arrays grown on a flexible carbon fiber paper,which can serve not only as a good pseudocapacitive material but also as a 3D conductive scaffold for loading additional electroactive materials.The resulting pseudocapacitive electrode is found to be superior to that based on the sibling NiCo2O4 nanorod arrays due to the much higher electrical conductivity of NiCo2S4.A series of electroactive metal oxide materials were deposited on the NiCo2S4 nanotube arrays by facile electro-deposition and their pseudocapacitive properties were explored and excellent results obtained.Finally,I will show some of our recent efforts on the use of three-dimensional nanostructured arrays for light-trapping enhanced photoelelctrochemical water splitting.