Effect of annealing on photovoltaic characteristics of nanostructured p-Cu2S/n-CdS thin film

Nanostructured heterojunction solar cells of CdS/Cu2S were grown by simple chemical ion exchange reaction by immersing the CdS thin films in Cu ion solution at room temperature. The as-grown nanostructured thin films were annealed at 250 °C in air for improving the interface and crystallinity of the heterojunction. These as grown and annealed nanostructured heterojunction were characterized for photovoltaic and other optoelectronic characteristics. Increase in conversion efficiency is obtained from annealed (η = 0.24%) than the as grown heterojunction (η = 0.09%), on illuminating to 100 mW/cm2 light source. The X-ray diffraction (XRD) pattern confirms improvement in crystallinity with increase in crystallite size from 29 to 32 nm on annealing. The optical absorbance strength observed to be increased along with red shift in energy band gap value from Eg = 2.02–2.20 eV after annealing.

[1]  F. Pfisterer,et al.  The wet-topotaxial process of junction formation and surface treatments of Cu2S–CdS thin-film solar cells , 2003 .

[2]  S. Kose,et al.  The effect of substrate temperature on the structural and some physical properties of ultrasonically sprayed CdS films , 2005 .

[3]  I. Repins,et al.  In Situ thickness measurements of chemical bath-deposited CdS , 2010 .

[4]  Ramphal Sharma,et al.  Effect of annealing on structural and optical properties of zinc oxide thin film deposited by successive ionic layer adsorption and reaction technique , 2009 .

[5]  Hongzheng Chen,et al.  Effects of molecular interface modification in CdS/polymer hybrid bulk heterojunction solar cells , 2010 .

[6]  C. Osterwald,et al.  Effect of air anneal temperature on the spectral response of CdS/CuInSe2 thin-film solar cells , 1985 .

[7]  Nicola Romeo,et al.  An innovative process suitable to produce high-efficiency CdTe/CdS thin-film modules , 2010 .

[8]  Xiaoming Li,et al.  Investigation on type-II Cu2S–CdS core/shell nanocrystals: synthesis and characterization , 2010 .

[9]  M. Ristova,et al.  XPS profile analysis on CdS thin film modified with Ag by an ion exchange , 2001 .

[10]  Sanghoo Park,et al.  Characterization of gallium-doped CdS thin films grown by chemical bath deposition , 2009 .

[11]  M. Gunasekaran,et al.  Photovoltaic cells based on pulsed electrochemically deposited SnS and photochemically deposited CdS and Cd1- xZnxS , 2007 .

[12]  A. Diniz,et al.  Crystallisation of indium-tin-oxide (ITO) thin films , 2004 .

[13]  K. Khan,et al.  Temperature effect on the electrical properties of undoped NiO thin films , 2009 .

[14]  K. Asokan,et al.  Structural and photoluminescence properties of swift heavy ion irradiated CdS thin films , 2006 .

[15]  R. Mane,et al.  Growth of nanocrystalline CuIn3Se5 (OVC) thin films by ion exchange reactions at room temperature and their characterization as photo-absorbing layers , 2009 .

[16]  Antonia Sonia A.C. Diniz,et al.  The effects of various annealing regimes on the microstructure and physical properties of ITO (In2O3:Sn) thin films deposited by electron beam evaporation for solar energy applications , 2011 .

[17]  C. Lokhande,et al.  Photoelectrochemical investigation of Ag2S thin films deposited by SILAR method , 2001 .

[18]  G. Russell,et al.  Degradation in CdS-Cu2S photovoltaic cells , 1992 .

[19]  Lin-Wang Wang,et al.  Spontaneous Superlattice Formation in Nanorods Through Partial Cation Exchange , 2007, Science.

[20]  M. Yamashita,et al.  Multilayer Structure Photovoltaic Cells , 2005 .

[21]  D. Acosta,et al.  Structural evolution and optical characterization of indium doped cadmium sulfide thin films obtained by spray pyrolysis for different substrate temperatures , 2004 .

[22]  D. Schmid,et al.  A comprehensive characterization of the interfaces in Mo/CIS/CdS/ZnO solar cell structures , 1994 .