Light absorption enhancement for ultra-thin Cu(In1−xGax)Se2 solar cells using closely packed 2-D SiO2 nanosphere arrays

Abstract 2-D closely packed SiO 2 nanosphere arrays serving as the photonic structure for light absorption enhancement on top of ultra-thin Cu(In 1− x Ga x )Se 2 solar cells are investigated both theoretically and experimentally. It is theoretically demonstrated that whispering gallery modes and high order Mie resonances contribute to the light absorption enhancement for the large spheres and an anti-reflection effect is prominent for small ones. The ultra-thin CIGSe solar cells achieve the optimum absorption enhancement for the small sphere array with a diameter of 110 nm, contrary to the larger spheres used in Si solar cells. The reason is attributed to the strong parasitic absorption in the AZO/ZnO/CdS front layers. They absorb mainly in the short wavelength range where the Mie resonances occur. Additionally, it is shown that the 110-nm-diameter sphere array exhibits a better angular tolerance than a conventional planar anti-reflection layer, which shows the potential as a promising anti-reflection structure.

[1]  M. Schmid,et al.  Enhanced performance of ultra-thin Cu(In,Ga)Se2 solar cells deposited at low process temperature , 2015 .

[2]  Kylie R. Catchpole,et al.  Optimal wavelength scale diffraction gratings for light trapping in solar cells , 2012 .

[3]  D. Lincot,et al.  Thinning of CIGS solar cells: Part II: Cell characterizations , 2011 .

[4]  M. Zeman,et al.  Plasmonic light trapping in thin-film silicon solar cells with improved self-assembled silver nanoparticles. , 2012, Nano letters.

[5]  Marika Edoff,et al.  Development of rear surface passivated Cu(In,Ga)Se2 thin film solar cells with nano-sized local rear point contacts , 2013 .

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

[7]  P. Belov,et al.  Photovoltaic absorption enhancement in thin-film solar cells by non-resonant beam collimation by submicron dielectric particles , 2013 .

[8]  Jonathan Grandidier,et al.  Light Absorption Enhancement in Thin‐Film Solar Cells Using Whispering Gallery Modes in Dielectric Nanospheres , 2011, Advanced materials.

[9]  Frank Schmidt,et al.  Adaptive finite element method for simulation of optical nano structures , 2007, 0711.2149.

[10]  Isabelle Gerard,et al.  Broadband light-trapping in ultra-thin nano-structured solar cells , 2013, Photonics West - Optoelectronic Materials and Devices.

[11]  R. Klenk.  Characterisation and modelling of chalcopyrite solar cells , 2001 .

[12]  H. Sodabanlu,et al.  Loss mitigation in plasmonic solar cells: aluminium nanoparticles for broadband photocurrent enhancements in GaAs photodiodes , 2013, Scientific Reports.

[13]  Yi Cui,et al.  Broadband light management using low-Q whispering gallery modes in spherical nanoshells , 2012, Nature Communications.

[14]  Martina Schmid,et al.  Light Coupling and Trapping in Ultrathin Cu(In,Ga)Se2 Solar Cells Using Dielectric Scattering Patterns. , 2015, ACS nano.

[15]  J. Sites,et al.  Potential of submicrometer thickness Cu(In,Ga)Se2 solar cells , 2005 .

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

[17]  Anatolii N Oraevsky,et al.  Whispering-gallery waves , 2002 .

[18]  Shaochen Chen,et al.  Enhanced photon absorption and carrier generation in nanowire solar cells. , 2012, Optics express.

[19]  M. Schmid,et al.  The effect of surface roughness on the determination of optical constants of CuInSe2 and CuGaSe2 thin films , 2013 .

[20]  Shiro Nishiwaki,et al.  Highly efficient Cu(In,Ga)Se2 solar cells grown on flexible polymer films. , 2011, Nature materials.

[21]  Witold Kandulski,et al.  Shadow Nanosphere Lithography , 2007 .

[22]  Colton R. Bukowsky,et al.  Solar cell efficiency enhancement via light trapping in printable resonant dielectric nanosphere arrays , 2013 .

[23]  Unyong Jeong,et al.  Assembled monolayers of hydrophilic particles on water surfaces. , 2011, ACS nano.

[24]  Martina Schmid,et al.  Plasmonic and photonic scattering and near fields of nanoparticles , 2014, Nanoscale Research Letters.

[25]  H. Atwater,et al.  Plasmonics for improved photovoltaic devices. , 2010, Nature materials.

[26]  Sergey Varlamov,et al.  Light trapping with titanium dioxide diffraction gratings fabricated by nanoimprinting , 2014 .

[27]  Nan Pan,et al.  Broadband absorption enhancement achieved by optical layer mediated plasmonic solar cell. , 2011, Optics express.

[28]  P. Barber.  Absorption and scattering of light by small particles , 1984 .

[29]  Dayu Zhou,et al.  Photonic crystal enhanced light-trapping in thin film solar cells , 2008 .

[30]  Jun Xu,et al.  Optical properties of nanocrystal-silicon thin films on silicon nanopillar arrays after thermal annealing , 2013 .

[31]  Daniel Lincot,et al.  Towards ultrathin copper indium gallium diselenide solar cells: proof of concept study by chemical etching and gold back contact engineering , 2012 .

[32]  J. Krč,et al.  Modeling plasmonic scattering combined with thin-film optics , 2011, Nanotechnology.