Hybrid Photovoltaic Cells and Related Methods

Abstract

Embodiments of the present invention involve photovoltaic (PV) cells comprising a semiconducting nanorod-nanocrystal-polymer hybrid layer, as well as methods for fabricating the same. In PV cells according to this invention, the nanocrystals may serve both as the light-absorbing material and as the heterojunctions at which excited electron-hole pairs split.

What is claimed is: 
     
         1 . A photovoltaic cell comprising:
 a. first and second electrodes;
 a. b. a plurality of semiconducting nanorods disposed between the electrodes, wherein the nanorods are electrically connected to the first electrode and electrically insulated from the second; 
   c. a plurality of photoresponsive nanocrystals bound to the nanorods via a bifunctional capping agent; and   d. a semiconductor polymer bound to the nanocrystals and bound the second electrode but not bound to the nanorods.   
     
     
         2 . The cell of  claim 1  wherein (i) the polymer is a hole-transfer polymer, (ii) the first charge carrier is electrons, and (iii) the second charge carrier is holes. 
     
     
         3 . The cell of  claim 2  wherein the polymer is poly(3-hexylthiophene), polyphenylenevinylene or a derivative thereof, or polyfluorene or a derivative thereof. 
     
     
         4 . The cell of  claim 1  wherein the nanorods are wide-bandgap semiconductors. 
     
     
         5 . The cell of  claim 4  wherein the nanorods comprise at least one of ZnO, SnO, and/or TiO 2 . 
     
     
         6 . The cell of  claim 1  wherein the nanorods are single-crystal nanorods. 
     
     
         7 . The cell of  claim 1  wherein the nanorods have an aspect ratio of at least 3. 
     
     
         8 . The cell of  claim 1  wherein the capping agent is mercaptoacetic acid. 
     
     
         9 . The cell of  claim 1  wherein absorption of light by a nanocrystal results in production of an exciton, the nanocrystal having a largest spatial dimension no greater than an average diffusion distance of the exciton. 
     
     
         10 . The cell of  claim 1  wherein the nanocrystals comprise at least one of CuInSe 2 , CuInS 2 , CuIn 1-x Ga x Se 2 , GaAs, InAs, InP, PbS, PbSe, PbTe, GaSb, InSb, CdTe and CdSe, wherein 0≦x≦1. 
     
     
         11 . The cell of  claim 1  wherein the nanocrystals have extinction coefficients of at least 100,000 M −1 cm −1 .