SBIR Phase I: Lateral Collection Polycrystalline Silicon Solar Cells

该小型企业创新研究（SBIR）第一阶段项目描述了一种创新概念，通过将吸收长度与少数载流子扩散长度分离来提高多晶硅太阳能电池的能量转换效率。 这种新的设计被称为横向收集。 制造路线采用可扩展的技术，如压印光刻和电沉积。主要的研究目标是证明与相同厚度的传统太阳能电池相比，多晶硅横向收集太阳能电池具有更高的电流。该项目的更广泛/商业影响将是显着提高多晶硅太阳能电池的能量转换效率的潜力。 降低多晶硅太阳能电池能量转换效率的一个主要因素是不能从吸收太阳光所需的相对厚的膜中收集载流子。具体地，最佳多晶硅吸收体厚度为10微米;然而，只有在电极的约3微米内产生电流时，才能提取电流。 这个问题的解决方案是解耦光吸收和电荷载流子收集的方向。通过将微尺度收集结构结合到活性层中，这种横向收集设计确保所有电荷载流子在收集表面的短距离内产生。该技术可以产生比传统设备多60%的电流，从而导致更高的能量转换效率。

This Small Business Innovation Research (SBIR) Phase I project describes an innovative concept to enhance the energy conversion efficiency of polycrystaline-Si solar cells by separating the absorption length from the minority carrier diffusion length. This new design is called lateral collection. The fabrication route employs scalable technologies such as imprint lithography and electrodeposition. The primary research objective is to demonstrate much higher current with polycrystalline silicon lateral collection solar cells compared to conventional solar cells of the same thickness.The broader/commercial impacts of this project will be the potential to significantly improve the energy conversion efficiency of polycrystalline Si solar cells. A major factor that lowers the energy conversion efficiency of polycrystalline silicon solar cell is that current carriers cannot be harvested from the relatively thick films that are needed to absorb sunlight. Specifically, the optimum polycrystalline silicon absorber thickness is 10 microns; however the current can only be extracted if it is generated within about 3 microns of the electrodes. The solution to this problem is to decouple the directions of light absorption and charge carrier collection. By incorporating microscale collecting structures into the active layer, this lateral collection design ensures that all charge carriers are generated within a short distance of a collecting surface. This technology may produce 60% more current than conventional devices, thus resulting in much higher energy conversion efficiency.