Tebyetekerwa Mike, Zhang Jian, Liang Kun, Duong The, Neupane Guru Prakash, Zhang Linglong, Liu Boqing, Truong Thien N, Basnet Rabin, Qiao Xiaojing, Yin Zongyou, Lu Yuerui, Macdonald Daniel, Nguyen Hieu T
Research School of Electrical, Energy and Materials Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT, 2601, Australia.
School of Mechatronic Engineering, Beijing Institute of Technology, Beijing, 100081, China.
Adv Mater. 2019 Jun;31(25):e1900522. doi: 10.1002/adma.201900522. Epub 2019 May 6.
One of the most fundamental parameters of any photovoltaic material is its quasi-Fermi level splitting (∆µ) under illumination. This quantity represents the maximum open-circuit voltage (V ) that a solar cell fabricated from that material can achieve. Herein, a contactless, nondestructive method to quantify this parameter for atomically thin 2D transition metal dichalcogenides (TMDs) is reported. The technique is applied to quantify the upper limits of V that can possibly be achieved from monolayer WS , MoS , WSe , and MoSe -based solar cells, and they are compared with state-of-the-art perovskites. These results show that V values of ≈1.4, ≈1.12, ≈1.06, and ≈0.93 V can be potentially achieved from solar cells fabricated from WS , MoS , WSe , and MoSe monolayers at 1 Sun illumination, respectively. It is also observed that ∆µ is inhomogeneous across different regions of these monolayers. Moreover, it is attempted to engineer the observed ∆µ heterogeneity by electrically gating the TMD monolayers in a metal-oxide-semiconductor structure that effectively changes the doping level of the monolayers electrostatically and improves their ∆µ heterogeneity. The values of ∆µ determined from this work reveal the potential of atomically thin TMDs for high-voltage, ultralight, flexible, and eye-transparent future solar cells.
任何光伏材料的最基本参数之一是其在光照下的准费米能级分裂（∆µ）。这个量代表了用该材料制造的太阳能电池所能达到的最大开路电压（V）。在此，报道了一种用于量化原子级薄的二维过渡金属二卤化物（TMD）这一参数的非接触、无损方法。该技术被用于量化基于单层WS、MoS、WSe和MoSe的太阳能电池可能实现的V的上限，并将它们与最先进的钙钛矿进行比较。这些结果表明，在1个太阳光照下，由WS、MoS、WSe和MoSe单层制造的太阳能电池分别可能实现约1.4 V、约1.12 V、约1.06 V和约0.93 V的V值。还观察到这些单层的不同区域的∆µ是不均匀的。此外，尝试通过在金属-氧化物-半导体结构中对TMD单层进行电门控来调控观察到的∆µ不均匀性，这有效地静电改变了单层的掺杂水平并改善了它们的∆µ不均匀性。这项工作确定的∆µ值揭示了原子级薄的TMD在用于高压、超轻、柔性和眼透明的未来太阳能电池方面的潜力。
