Synthesis and characterization of 15% efficient CIGSSe solar cells from nanoparticle inks

We report a total-area power conversion efficiency of 15% for a copper indium gallium disulfoselenide (CIGSSe) solar cell fabricated from a copper indium gallium disulfide (CIGS) nanoparticle ink based process. Careful optimization of the fabrication process has resulted in a significant improvement in efficiency compared to our previously reported efficiency of 12%. This efficiency ranks among the highest reported in the literature for solution processed CIGSSe. Despite having an absorber thickness of approximately 700-800nm, which is less than half the thickness of high efficiency devices grown by both coevaporation and solution processes in the literature, our devices show good short-circuit current (32.1mA/cm(2)). Surprisingly, the sintered film shows lateral composition fluctuations, which have not been reported for other high efficiency devices and may be responsible for the lower open circuit voltage (636mV) observed here. This suggests an avenue for further improvement through optimization of the nanoparticle selenization process to better control composition in the sintered film. Copyright (c) 2015 John Wiley & Sons, Ltd.

[1]  Copper indium gallium selenide (CIGS) photovoltaic devices made using multistep selenization of nanocrystal films. , 2013, ACS applied materials & interfaces.

[2]  Rakesh Agrawal,et al.  Cu2ZnSn(S,Se)4 solar cells from inks of heterogeneous Cu–Zn–Sn–S nanocrystals , 2014 .

[3]  Uwe Rau,et al.  A new approach to high-efficiency solar cells by band gap grading in Cu(In,Ga)Se2 chalcopyrite semiconductors , 2001 .

[4]  Rakesh Agrawal,et al.  Sulfide nanocrystal inks for dense Cu(In1-xGa(x))(S1-ySe(y))2 absorber films and their photovoltaic performance. , 2009, Nano letters.

[5]  H. Hillhouse,et al.  Ink formulation and low‐temperature incorporation of sodium to yield 12% efficient Cu(In,Ga)(S,Se)2 solar cells from sulfide nanocrystal inks , 2013 .

[6]  Steven S. Hegedus,et al.  Thin‐film solar cells: device measurements and analysis , 2004 .

[7]  Rakesh Agrawal,et al.  Earth Abundant Element Cu2Zn(Sn1−xGex)S4 Nanocrystals for Tunable Band Gap Solar Cells: 6.8% Efficient Device Fabrication , 2011 .

[8]  D. Hariskos,et al.  High-efficiency Cu(In,Ga)Se2 cells and modules , 2013 .

[9]  Rakesh Agrawal,et al.  Fabrication of 7.2% efficient CZTSSe solar cells using CZTS nanocrystals. , 2010, Journal of the American Chemical Society.

[10]  Rommel Noufi,et al.  Band-gap engineering in Cu(In,Ga) Se2 thin films grown from (In,Ga)2Se3 precursors , 1996 .

[11]  M. Bodegård,et al.  Influence of the Cu(In,Ga)Se2 thickness and Ga grading on solar cell performance , 2003 .

[12]  Rakesh Agrawal,et al.  9.0% efficient Cu2ZnSn(S,Se)4 solar cells from selenized nanoparticle inks , 2015 .

[13]  L. Kranz,et al.  Flexible Cu(In,Ga)Se2 solar cells with reduced absorber thickness , 2015 .

[14]  H. Schock,et al.  Co-evaporation of Cu(In, Ga)Se2 at low temperatures: An In-Situ x-ray growth analysis , 2013, 2013 IEEE 39th Photovoltaic Specialists Conference (PVSC).

[15]  Jürgen H. Werner,et al.  Radiative efficiency limits of solar cells with lateral band-gap fluctuations , 2004 .

[16]  J. Sites,et al.  Band-gap grading in Cu(In,Ga)Se2 solar cells , 2005 .

[17]  Tayfun Gokmen,et al.  Solution‐processed Cu(In,Ga)(S,Se)2 absorber yielding a 15.2% efficient solar cell , 2013 .

[18]  Rommel Noufi,et al.  Progress toward 20% efficiency in Cu(In,Ga)Se2 polycrystalline thin‐film solar cells , 1999 .

[19]  H. Schock,et al.  Study of the effect of gallium grading in Cu(In,Ga)Se2 , 2000 .

[20]  H. Queisser,et al.  Detailed Balance Limit of Efficiency of p‐n Junction Solar Cells , 1961 .

[21]  Tayfun Gokmen,et al.  Beyond 11% Efficiency: Characteristics of State‐of‐the‐Art Cu2ZnSn(S,Se)4 Solar Cells , 2013 .

[22]  D. Hariskos,et al.  New world record efficiency for Cu(In,Ga)Se2 thin‐film solar cells beyond 20% , 2011 .

[23]  Jürgen H. Werner,et al.  Efficiency limitations of polycrystalline thin film solar cells: case of Cu(In,Ga)Se2 , 2005 .

[24]  Wei Wang,et al.  8.01% CuInGaSe2 solar cells fabricated by air-stable low-cost inks. , 2012, Physical chemistry chemical physics : PCCP.

[25]  W. Warta,et al.  Solar cell efficiency tables (version 43) , 2014 .

[26]  D. Abou‐Ras,et al.  Improved performance of Ge‐alloyed CZTGeSSe thin‐film solar cells through control of elemental losses , 2015 .

[27]  J. Werner,et al.  High quality baseline for high efficiency, Cu(In1−x,Gax)Se2 solar cells , 2007 .

[28]  Dongwook Lee,et al.  Superstrate CuInS2 photovoltaics with enhanced performance using a CdS/ZnO nanorod array. , 2012, ACS applied materials & interfaces.

[29]  T. Unold,et al.  Real-time observation of Cu2ZnSn(S,Se)4 solar cell absorber layer formation from nanoparticle precursors. , 2013, Physical chemistry chemical physics : PCCP.

[30]  H. Hillhouse,et al.  Enhancing the performance of CZTSSe solar cells with Ge alloying , 2012 .

[31]  R. Scheer.  Activation energy of heterojunction diode currents in the limit of interface recombination , 2009 .