Hebei Key Lab of Optic-Electronic Information and Materials, College of Physics Science and Technology , Hebei University , Baoding 071002 , China.
State Key Laboratory of Photovoltaic Materials & Technology , Yingli Green Energy Holding Co., Ltd. , Baoding 071051 , China.
ACS Appl Mater Interfaces. 2018 Dec 26;10(51):44890-44896. doi: 10.1021/acsami.8b17379. Epub 2018 Dec 12.
Crystalline silicon (c-Si) solar cells remain dominant in the photovoltaic (PV) market because of their cost-effective advantages. However, the requirement for expensive vacuum equipment and the power-hungry thermal budget for surface passivation technology, which is one of the key enablers of the high performance of c-Si solar cells, impede further reductions of costs. Thus, the omission of the vacuum and high-temperature process without compromising the passivation effect is highly desirable due to cost concerns. Here, we demonstrate a vacuum-free, room-temperature organic Nafion thin-film passivation scheme with an effective minority carrier lifetime (τ) exceeding 9 ms on an n-type c-Si wafer with a resistivity of 1-5 Ω·cm, corresponding to an implied open circuit voltage (i V) of 724 mV and upper-limit surface recombination velocity (SRV) of 1.46 cm/s, which is a level that is in line with the hydrogenated amorphous Si film-passivation scheme used in the current PV industry. We find that the Nafion film passivation of Si can be enhanced in an O atmosphere and that the Nafion/c-Si interface oxidation should be responsible for the passivation mechanism. This highly effective passivation is also achieved on various micro-/nanotextured Si surface structures from actual production, including a pyramidal surface and nanopore-pyramid hybrid structure with nanopores on the inclined plane of the pyramid. We develop an organic Nafion-passivated n-type back-junction Si solar cell to examine application in a real device. The open circuit voltage ( V) of the solar cell with the Nafion passivation layer achieves a clear improvement (30.8 mV) over those without the passivation layer, resulting in an increase (1.5%) in the power conversion efficiency. These results suggest the potential use of these organic electronics with current Si microelectronics and a new strategy for the development of vacuum-free, low-temperature Si-based PVs at low cost.
晶体硅 (c-Si) 太阳能电池因其具有成本效益优势，在光伏 (PV) 市场中仍占主导地位。然而，昂贵的真空设备要求以及表面钝化技术的高能耗热预算，这是 c-Si 太阳能电池高性能的关键推动因素之一，阻碍了成本的进一步降低。因此，由于成本问题，人们非常希望在不牺牲钝化效果的情况下省略真空和高温工艺。在这里，我们展示了一种无需真空、在室温下使用有机 Nafion 薄膜的钝化方案，在电阻率为 1-5 Ω·cm 的 n 型 c-Si 晶片上，有效少数载流子寿命 (τ) 超过 9 ms，对应的隐含开路电压 (i V) 为 724 mV，表面复合速度上限 (SRV) 为 1.46 cm/s，这一水平与当前光伏产业中使用的氢化非晶硅薄膜钝化方案相当。我们发现，在 O 气氛中，Nafion 对 Si 的钝化作用可以增强，而 Nafion/c-Si 界面氧化应该是钝化机制的原因。这种高效的钝化在各种来自实际生产的微纳结构化 Si 表面结构上也可以实现，包括金字塔表面和纳米孔-金字塔混合结构，在金字塔的斜面上具有纳米孔。我们开发了一种有机 Nafion 钝化的 n 型背结 Si 太阳能电池，以检验其在实际器件中的应用。具有 Nafion 钝化层的太阳能电池的开路电压 (V) 明显优于没有钝化层的太阳能电池，因此，其功率转换效率提高了 (1.5%)。这些结果表明，这些有机电子器件有可能与当前的 Si 微电子器件结合使用，并为开发低成本、无需真空、低温 Si 基光伏器件提供了一种新策略。
