Liang Bingquan, Chen Xinliang, Yuan Heze, Wang Xuejiao, Hou Guofu, Zhao Ying, Zhang Xiaodan
Institute of Photoelectronic Thin Film Devices and Technology, Nankai University, Tianjin 300350, China.
Tianjin Key Laboratory of Efficient Utilization of Solar Energy, , Nankai University, Tianjin 300350, China.
ACS Omega. 2024 Dec 6;9(50):49935-49944. doi: 10.1021/acsomega.4c09080. eCollection 2024 Dec 17.
Silicon heterojunction (SHJ) solar cells, as one of the most promising passivated contact solar cell technologies of the next generation, have the advantages of high conversion efficiency, high open-circuit voltage, low-temperature coefficient, and no potential-induced degradation. For the single-side rear-emitter SHJ solar cells, the n-type carrier selective layer, which serves as the light-incident side, plays a pivotal role in determining the performance of heterojunction devices. Consequently, a superior n-doped layer should exhibit high optical transmittance and minimal optical absorption, along with a substantial effective doping level to guarantee the formation of dark conductivity (σ) and electron-transport capacity. In this work, we investigated the optical and electrical properties of different n-type monolayers and stacked gradient multilayers, including monolayer, bilayer, and trilayer Si-based thin films, acting as electron-transport layers (ETL) prepared by plasma-enhanced chemical vapor deposition, and studied the influences of these above layers on the performance of SHJ solar cells. The experimental results demonstrate that the ETL with an n-nc-Si:H/n-nc-SiOx:H/n-nc-Si:H trilayer structure exhibits the potential to boost highly efficient solar cells. The bottom highly crystallized, lightly phosphorus-doped n-nc-Si:H film promotes rapid nucleation of the intermediate n-nc-SiOx:H film and thus reduces the thickness of the incubation layer, as well as improves the passivation contact. The n-nc-SiOx:H film in the middle layer provides excellent optical properties and reduces parasitic absorption, thereby increasing the short-circuit current density. Furthermore, the highly doped n-nc-Si:H at the top offers an optimal ohmic contact with the reactive plasma deposition-grown TCO layer, which ultimately enhances the fill factor. Ultimately, a conversion efficiency of 20.41%, with an open-circuit voltage of 720 mV, a short-circuit current density of 39.34 mA/cm, and a filling factor of 72.05%, was achieved in the SHJ solar cell using a typical trilayer structure. This kind of trilayer structure has a particular significance for potential industrialized applications as it allows for efficient utilization of solar energy.
硅异质结（SHJ）太阳能电池作为下一代最具潜力的钝化接触太阳能电池技术之一，具有转换效率高、开路电压高、温度系数低以及无潜在诱导退化等优点。对于单侧背接触SHJ太阳能电池，作为光入射侧的n型载流子选择层在决定异质结器件性能方面起着关键作用。因此，优异的n掺杂层应具有高光学透过率和最小光学吸收，以及足够高的有效掺杂水平，以确保形成暗电导率（σ）和电子传输能力。在本工作中，我们研究了不同n型单层和堆叠梯度多层膜的光学和电学性质，包括单层、双层和三层硅基薄膜，它们作为通过等离子体增强化学气相沉积制备的电子传输层（ETL），并研究了上述这些层对SHJ太阳能电池性能的影响。实验结果表明，具有n-nc-Si:H/n-nc-SiOx:H/n-nc-Si:H三层结构的ETL具有推动高效太阳能电池发展的潜力。底部高度结晶、轻掺杂磷的n-nc-Si:H膜促进了中间n-nc-SiOx:H膜的快速成核，从而减小了孕育层的厚度，并改善了钝化接触。中间层的n-nc-SiOx:H膜具有优异的光学性质并减少了寄生吸收，从而提高了短路电流密度。此外，顶部高度掺杂的n-nc-Si:H与反应等离子体沉积生长的TCO层提供了最佳的欧姆接触，最终提高了填充因子。最终，在采用典型三层结构的SHJ太阳能电池中实现了20.41%的转换效率，开路电压为720 mV，短路电流密度为39.34 mA/cm，填充因子为72.05%。这种三层结构对于潜在的工业化应用具有特殊意义，因为它能够实现太阳能的高效利用。
