Metal chalcogenide nanoparticles for preparing light absorption layer of solar cells and method of preparing the same

Abstract

Disclosed are metal chalcogenide nanoparticles forming a light absorption layer of solar cells including a first phase including copper (Cu)-tin (Sn) chalcogenide and a second phase including zinc (Zn) chalcogenide, and a method of preparing the same.

1 . A metal chalcogenide nanoparticles forming a light absorption layer of solar cells comprising a first phase comprising copper (Cu)-tin (Sn) chalcogenide and a second phase comprising zinc (Zn) chalcogenide. 
     
     
         2 . The metal chalcogenide nanoparticles according to  claim 1 , wherein the copper (Cu)-tin (Sn) chalcogenide is CuaSnSb wherein 1.2≦a≦3.2 and 2.5≦b≦4.5, and/or CuxSnSey wherein 1.2≦x≦3.2 and 2.5≦y≦4.5. 
     
     
         3 . The metal chalcogenide nanoparticles according to  claim 1 , wherein the zinc (Zn) chalcogenide is ZnS and/or ZnSe. 
     
     
         4 . The metal chalcogenide nanoparticles according to  claim 1 , wherein the first phase and the second phase exist independently. 
     
     
         5 . The metal chalcogenide nanoparticles according to  claim 1 , wherein a composition ratio of a metal in the metal chalcogenide nanoparticles is determined in a range of 0.5≦Cu/(Zn+Sn)≦1.5 and 0.5≦Zn/Sn≦2.0. 
     
     
         6 . The metal chalcogenide nanoparticles according to  claim 1 , wherein the first phase and the second phase are evenly distributed in metal chalcogenide nanoparticles. 
     
     
         7 . The metal chalcogenide nanoparticles according to  claim 6 , wherein, when a certain area in the metal chalcogenide is observed, a composition ratio of a metal in metal chalcogenide nanoparticles in the area is determined in a range of 0.5≦Cu/(Zn+Sn)≦1.5 and 0.5≦Zn/Sn≦2.0. 
     
     
         8 . (canceled) 
     
     
         9 . The metal chalcogenide nanoparticles according to  claim 1 , wherein the metal chalcogenide nanoparticles are a complex of the first phase and the second phase existing in a bulk. 
     
     
         10 . The metal chalcogenide nanoparticles according to  claim 1 , wherein the metal chalcogenide nanoparticles are nanoparticles having a core-shell structure comprising a core consisting of the first phase and a shell consisting of the second phase. 
     
     
         11 . The metal chalcogenide nanoparticles according to  claim 10 , wherein the core has a diameter of 5 nanometers to 200 nanometers. 
     
     
         12 . The metal chalcogenide nanoparticles according to  claim 10 , wherein the shell has a thickness of 1 nanometer to 100 nanometers. 
     
     
         13 . A method of synthesizing metal chalcogenide nanoparticles according to  claim 1 , the method comprising:
 preparing a first solution comprising at least one Group VI source selected from the group consisting of compounds comprising sulfur (S) or selenium (Se);   preparing a second solution comprising a copper (Cu) salt and a tin (Sn) salt and a third solution comprising a zinc (Zn) salt;   mixing and reacting the first solution and the second solution; and   mixing and reacting the third solution with a reaction product of the mixing and reacting.   
     
     
         14 . The method according to  claim 13 , wherein, when the third solution of the mixing and reacting is mixed, a Group VI source is further added. 
     
     
         15 - 17 . (canceled) 
     
     
         18 . An ink composition for preparing a light absorption layer comprising the metal chalcogenide nanoparticles according to  claim 1 . 
     
     
         19 . A method of preparing a thin film using the ink composition for preparing the light absorption layer according to  claim 18 , the method comprising:
 dispersing metal chalcogenide nanoparticles comprising a first phase comprising copper (Cu)-tin (Sn) chalcogenide and a second phase comprising zinc (Zn) chalcogenide in a solvent to prepare an ink composition;   coating the ink composition on a base provided with an electrode; and   drying and then heat-treating the ink composition coated on the base provided with an electrode.   
     
     
         20 . (canceled) 
     
     
         21 . The method according to  claim 19 , wherein the ink composition of the dispersing is prepared by further adding an additive. 
     
     
         22 . The method according to  claim 19 , wherein the additive is at least one selected from the group consisting of polyvinylpyrrolidone (PVP), polyvinyl alcohol, Anti-terra 204, Anti-terra 205, ethyl cellulose, and DispersBYK110. 
     
     
         23 . The method according to  claim 19 , wherein the coating is performed by wet coating, spray coating, doctor blade coating and inkjet-printing. 
     
     
         24 . The method according to  claim 19 , wherein the heat-treating is performed in a range of 400 to 900° C. 
     
     
         25 . The method according to  claim 19 , wherein, in the dispersing, S and/or Se is dispersed in a particle type with the metal chalcogenide nanoparticles in a solvent. 
     
     
         26 - 30 . (canceled)