The optical and electrical properties of quantum dots (QDs) have generated great interest in the use of QDs for photovoltaics. The optical coupling of QDs with currently manufactured solar cells is one of the most promising photovoltaic applications of QDs. Here we demonstrate that by spin-coating Si-QD ink at the solar cell surface the efficiency of screen-printed Si solar cells may be improved. The enhancement of solar cell efficiency results from the porous Si-QD film induced increase of light absorption. The solar cell efficiency may be further improved as the efficiency of down-shifting short-wavelength light to red light by Si-QDs increases. (C) 2011 Elsevier B.V. All rights reserved.