应变纤锌矿In_(x)Ga_(1-x)N/ZnSnN_(2)核/壳量子点太阳能电池的光电转换效率

Conversion Efficiency of Strained Wurtzite ZnSnN_(2)/In_(x)Ga_(1-x)N Core/Shell Quantum Dot Solar Cells

在有效质量近似下,考虑晶格失配产生的应变影响对材料性质的调节,从理论上研究了应变纤锌矿In_(x)Ga_(1-x)N/ZnSnN_(2)核/壳量子点太阳能电池的光电转换效率、开路电压和短路电流密度随核、壳尺寸的变化关系,以及In含量光电转换效率的关系。数值计算结果表明:随着核尺寸的增加,开路电压随之增加,而短路电流密度与光电转换效率则减小;随壳尺寸的增加,开路电压单调递减,短路电流密度和光电转换效率则单调递增;光电转换效率随In组分增加单调递增。此外,应变会使得量子点带隙变大,从而导致开路电压增大,而光电转换效率和短路电流密度则减小。

On the basis of the effective mass approximation,considering the strain effect caused by lattice mismatch,the variation of the photoelectric conversion efficiency,open-circuit voltage and short-circuit current density of strained wurtzite In_(x)Ga_(1-x)N/ZnSnN_(2)core/shell quantum dots with the core and shell sizes,and the relationship between the In content and the photoelectric conversion efficiency of solar cells have been theoretically studied.The numerical results show that with the increase of the core size,the open-circuit voltage of quantum dots increases,but the short-circuit current density and photoelectric conversion efficiency decrease;with increase of shell size,the open-circuit voltage decreases monotonically,but the short-circuit current density and the photoelectric conversion efficiency increase monotonically;the photoelectric conversion efficiency increases monotonically with increase of the In composition.In addition,the strain will increase the quantum dot band gap,thus open-circuit voltage increases,but the photoelectric conversion efficiency and short-circuit current density decrease.