Parajuli D, Kc Devendra, Khattri Khim B, Adhikari Dipak Raj, Gaib Raid Anam, Shah Deb Kumar
Research Center for Applied Science and Technology, Tribhuvan University, Kirtipur, 44613, Nepal.
, Lebesby Kommune, Norway.
Sci Rep. 2023 Jul 27;13(1):12193. doi: 10.1038/s41598-023-38906-z.
In this work, a numerical assessment of the optoelectrical properties of the ZnO-ZnSe-CdSe heterojunction for a thin and cost-effective solar cell was made by using the PC1D simulation software. The photovoltaic (PV) properties have been optimized by varying thicknesses of the absorber layer of the p-CdSe layer, the window layer of n-ZnSe, and the antireflection coating (ARC) layer of ZnO, a transparent conductive oxide with enhanced light trapping, and wide bandgap engineering. There is a positive conduction band offset (CBO) of ΔEc = 0.25 eV and a negative valence band offset (VBO) of ΔEv = 1.2 - 2.16 = - 0.96 eV. The positive CBO prevents the flow of electrons from the CdSe to the ZnSe layer. Further, the impact of doping concentration on the performance of solar cells has been analyzed. The simulation results reveal the increase in the efficiency of solar cells by adding an ARC. The rapid and sharp increase in the efficiency with the thickness of the window layer beyond 80 nm is interesting, unusual, and unconventional due to the combined effect of morphology and electronics on a macro-to-micro scale. The thin-film solar cell with the structure of ZnO/ZnSe/CdSe exhibited a high efficiency of 11.98% with short-circuit current (I) = 1.72 A, open-circuit voltage (V) = 0.81 V and fill factor (FF) = 90.8% at an optimized thickness of 2 μm absorber layer, 50 nm window layer, and 78 nm ARC layer. The EQE of solar cells has been observed at about 90% at a particular wavelength at 470 nm (visible light range). Around 12% of efficiency from such a thin-layered solar cell is highly applicable.
在这项工作中，通过使用PC1D模拟软件对用于薄型且经济高效的太阳能电池的ZnO-ZnSe-CdSe异质结的光电特性进行了数值评估。通过改变p-CdSe层的吸收层、n-ZnSe的窗口层以及具有增强光捕获功能的透明导电氧化物ZnO的抗反射涂层（ARC）层的厚度，对光伏（PV）特性进行了优化，并进行了宽带隙工程。存在正的导带偏移（CBO），ΔEc = 0.25 eV，以及负的价带偏移（VBO），ΔEv = 1.2 - 2.16 = -0.96 eV。正的CBO阻止电子从CdSe流向ZnSe层。此外，分析了掺杂浓度对太阳能电池性能的影响。模拟结果表明添加ARC可提高太阳能电池的效率。由于宏观到微观尺度上形态学和电子学的综合作用，当窗口层厚度超过80 nm时，效率随着窗口层厚度的增加而快速且急剧增加，这是有趣的、不寻常的和非常规的。具有ZnO/ZnSe/CdSe结构的薄膜太阳能电池在吸收层厚度为2μm、窗口层厚度为50 nm和ARC层厚度为78 nm的优化厚度下，表现出11.98%的高效率，短路电流（I）= 1.72 A，开路电压（V）= 0.81 V，填充因子（FF）= 90.8%。在470 nm（可见光范围）的特定波长下，太阳能电池的外量子效率（EQE）约为90%。这种薄层层状太阳能电池约12%的效率具有很高的适用性。
