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Cao Y.,Northeast Dianli University | Cao Y.,Nankai University | Cao Y.,Key Laboratory of Photo Electronics Thin Film Devices and Technique of Tianjin | Cao Y.,Key Laboratory of Optoelectronics Information Science and Technology | And 8 more authors.
Journal of Alloys and Compounds | Year: 2015

In this work, hydrogenated microcrystalline silicon germanium (μc-SiGe:H) thin film solar cells with a novel band gap grading profile have been designed. By comparing different profile types (normal profile, reverse profile and no profile), the normal profile was formed in sequence by the superposition of a high Ge content layer, a Ge content grading layer and a μc-Si:H layer has been proposed. This structure exhibits higher short-circuit current density (Jsc) than conventional cell design with the similarly Ge content owing to the enhancement of the infrared response. Finally, an initial efficiency of 6.53% was achieved by μc-SiGe:H solar cell with this novel cell structure. The results have demonstrated a great potential of the μc-SiGe:H solar cells as the infrared absorber in multi-junction silicon based thin film solar cells. © 2015 Elsevier B.V.

Ma J.,Key Laboratory of Photo Electronics Thin Film Devices and Technique of Tianjin | Ma J.,Nankai University | Ni J.,Nankai University | Zhang J.,Key Laboratory of Photo Electronics Thin Film Devices and Technique of Tianjin | And 7 more authors.
Thin Solid Films | Year: 2014

Boron doped nanocrystalline-Si:H/a-SiCx:H (nc-Si:H/a-SiCx:H) quantum dot superlattice has been prepared by plasma enhanced chemical vapor deposition at a low temperature of 150 °C. This method for fabricating superlattice allows controlling both the size and density of Si quantum dots in potential well and the characteristics of potential barrier without subsequent annealing treatment. Cross-section high resolution transmission electron microscopy investigations confirm the periodic multi-layer structure of silicon quantum dots (~ 2 nm diameter) separated by a-SiCx:H matrix (2-3 nm thickness) with sharp interface. With strong blue photoluminescence and high perpendicular conductivity, boron doped nc-Si:H/a-SiCx:H quantum dot superlattice shows great advantages in obtaining applicable blue light emission. © 2014 Elsevier B.V. All rights reserved.

Huang Z.-H.,Nankai University | Huang Z.-H.,Key Laboratory of Photo Electronics Thin Film Devices and Technique of Tianjin | Zhang J.-J.,Nankai University | Zhang J.-J.,Key Laboratory of Photo Electronics Thin Film Devices and Technique of Tianjin | And 6 more authors.
Chinese Physics B | Year: 2014

In this article, a new type of superimposing morphology comprised of a periodic nanostructure and a random structure is proposed for the first time to enhance the light scattering in silicon-based thin film solar cells. According to the framework of the Reyleigh - Sommerfeld diffraction algorithm and the experimental results of random morphologies, we analyze the light-scattering properties of four superimposing morphologies and compare them with the individual morphologies in detail. The results indicate that the superimposing morphology can offer a better light trapping capacity, owing to the coexistence of the random scattering mechanism and the periodic scattering mechanism. Its scattering property will be dominated by the individual nanostructures whose geometrical features play the leading role. © 2014 Chinese Physical Society and IOP Publishing Ltd.

Huang Q.,Nankai University | Huang Q.,Key Laboratory of Photo Electronics Thin Film Devices and Technique of Tianjin | Huang Q.,Key Laboratory of Optoelectronic Information Science and Technology | Zhang D.,Nankai University | And 17 more authors.
Solar Energy Materials and Solar Cells | Year: 2015

Advanced light management currently plays an important role in high-performance solar cells. In this paper, a HAZO/AZO structure that was produced using RF-magnetron sputtering with segmented hydrogen mediation was proposed to further simultaneously enhance the transmittance and light trapping capability at full solar spectrum. Compared to the standard AZO front contact, the total transmittance at short wavelength and haze at full spectrum were remarkably enhanced by 5.1% and 20.7%, respectively. Additionally, the resistivity of the HAZO/AZO structure was enhanced by 16.9%. When applied as front electrodes, the spectral response of a-Si:H and μc-Si:H solar cells increased. The quantum efficiency of the a-Si:H solar cell improved by 7.9% (from 59% to 66.9%) at 400 nm. An initial efficiency of 8.69% with Jsc over 27 mA/cm2 was obtained for the μc-Si:H solar cell. Finally, an a-Si:H/a-SiGe:H/μc-Si:H triple-junction solar cell was obtained with the initial efficiency over 15%, which illustrates a promising and potentially cost-effective alternative structure to further improve the high-quality transparent electrodes for high-efficiency thin-film solar cells. © 2014 Elsevier B.V. All rights reserved.

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