Broadband Enhancement in Thin-Film Amorphous Silicon Solar Cells Enabled by Nucleated Silver Nanoparticles

Abstract

Recently plasmonic effects have gained tremendous interest in solar cell research because they are deemed to be able to dramatically boost the efficiency of thin-film solar cells. However, despite of the intensive efforts, the desired broadband enhancement, which is critical for real device performance improvement, has yet been achieved with simple fabrication and integration methods appreciated by the solar industry. We propose in this paper a novel idea of using nucleated silver nanoparticles to effectively scatter light in a broadband wavelength range to realize pronounced absorption enhancement in the silicon absorbing layer. Since it does not require critical patterning, experimentally these tailored nanoparticles were achieved by the simple, low-cost and upscalable wet chemical synthesis method and integrated before the back contact layer of the amorphous silicon thin-film solar cells. The solar cells incorporated with 200 nm nucleated silver nanoparticles at 10% coverage density clearly demonstrate a broadband absorption enhancement and significant superior performance including a 14.3% enhancement in the short-circuit photocurrent density and a 23% enhancement in the energy conversion efficiency, compared with the randomly textured reference cells without nanoparticles. Among the measured plasmonic solar cells the highest efficiency achieved was 8.1%. The significant enhancement is mainly attributed to the broadband light scattering arising from the integration of the tailored nucleated silver nanoparticles.

Exceeding the limit of plasmonic light trapping in textured screen-printed solar cells using Al nanoparticles and wrinkle-like graphene sheets

“…11 The surface coverage can be tailored by adjusting the suspension concentrations. The single screen-printed crystalline solar cells, which were purchased from Suntech Power Holdings Co., Ltd., were composed of p-type Si wafers with geometries of silver finger/75 nm SiN/180 mm c-Si with front texture and Ag/Al back contact.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14] Because plasmonic nanoparticles are integrated into photovoltaic devices with relatively low surface coverages (typically less than 30%), light-trapping effects increase solar cell absorption and enhance the short-circuit photocurrent density (J sc ) of not only newgeneration solar cells (organic solar cells and dye-sensitized solar cells), 1,2 but textured screen-printed silicon solar cells 12,13 which dominate the photovoltaic market. However, plasmonic nanostructures suffer from parasitic absorption that cannot contribute to photocurrents; thus, the performance of plasmonic solar cells is limited.…”

“…However, current research on plasmonic solar cells focuses on Ag nanoparticle-enhanced and Au nanoparticle-enhanced solar cells. [1][2][3][4][5][6][7][8][9][10][11]13,14 Al nanoparticle-enhanced solar cells have not been realized because a method to simultaneously synthesize Al nanoparticles and control the low surface coverage has not been developed. An Al nanostructure is too active to be produced by a wet-chemical method under ambient temperatures.…”

Nanoplasmonics: a frontier of photovoltaic solar cells

“…2 The Ag nanostructure acts as plasmonic BSR, and it also causes uneven active layers of the cells, which also scatters the light. of the metal element and the structure volume can achieve a relatively large scattering cross section and a small absorption cross section, increasing the scattering/absorption ratio of the metal nanostructure [30,41] ; when the metal nanostructures are coated with dielectric materials, the absorption peak can shift away from the scattering peak to insignifi cant wavelengths, leaving the scattering peak at the important wavelengths for maximum light enhancement [42,43] ; rearlocated nanostructures in a PV device do not suffer from the dissipated absorption of the short wavelength light in the metal, as this range of light is absorbed by the solar cell active layer during the its fi rst pass through it [12,16,18,24,[36][37][38]44] ; we recently reported that by using a nanomaterial (such as Al) whose SPR wavelength is shorter than the lower end of the absorption band of the PV device, the metal absorption can be minimized and the forward scattering can still be mostly preserved [45] . For PV devices with heavily damped semiconductors, their active layers are able to compete with unwanted metal absorption.…”

Numerical simulation of plasmonic effects in amorphous silicon induced by embedded aluminium nanoparticles

“…The LSPR condition depends on the on the metal/interface properties, on the particle size and shape, and finally on the average distance in the particle distribution [4,5]. Light trapping for improving solar cell efficiency based on plasmonic effects is reported in literature mainly for silver nanoparticles embedded in silicon solar cells [6,7] and in thin film amorphous silicon solar cells [8,9]. Reports on Aluminium nanoparticles embedded in a-Si:H solar cells have also been recently published [10,11,12].…”