We demonstrate through precise numerical simulations the possibility of flexible, thin-film solar cells, consisting of crystalline silicon, to achieve power conversion efficiency of 31%. Our optimized photonic crystal architecture consists of a 15 μm thick cell patterned with inverted micro-pyramids with lattice spacing comparable to the wavelength of near-infrared light, enabling strong wave-interference based light trapping and absorption. Unlike previous photonic crystal designs, photogenerated charge carrier flow is guided to a grid of interdigitated back contacts with optimized geometry to minimize Auger recombination losses due to lateral current flow. Front and back surface fields provided by optimized Gaussian doping profiles are shown to play a vital role in enhancing surface passivation. We carefully delineate the drop in power conversion efficiency when surface recombination velocities exceed 100 cm/s and the doping profiles deviate from prescribed values. These results are obtained by exact numerical simulation of Maxwell’s wave equations for light propagation throughout the cell architecture and a state-of-the-art model for charge carrier transport and Auger recombination.
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机译:通过精确的数值模拟,我们证明了由晶体硅构成的柔性薄膜太阳能电池实现31%的功率转换效率的可能性。我们优化的光子晶体架构包括一个15μm厚的单元,该单元以倒置的微金字塔构图,其晶格间距可与近红外光的波长相媲美,从而实现了基于强波干扰的光捕获和吸收。与以前的光子晶体设计不同,光生载流子被引导到具有优化几何形状的叉指式背面接触的网格中,以最小化由于横向电流而产生的俄歇复合损失。优化的高斯掺杂分布提供的前表面场和后表面场在增强表面钝化方面起着至关重要的作用。当表面复合速度超过100 cm / s且掺杂分布偏离规定值时,我们仔细描述了功率转换效率的下降。这些结果是通过麦克斯韦的波动方程的精确数值模拟获得的,该波动方程用于光在整个电池结构中的传播,以及用于电荷载流子传输和俄歇复合的最新模型。
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