MoO_x缓冲层对backwall型超薄CdTe太阳电池性能的模拟

Numerical simulation of ultra-thin CdTe solar cells with a buffer layer of MoO_x in backwall configuration

采用SCAPS模拟软件对backwall型结构(glass/ITO/MoO_x/CdTe/CdS/SnO_2/Ag)的超薄CdTe太阳电池的性能进行了模拟研究。在backwall型超薄CdTe电池中,CdTe吸收层为迎光面,入射光从CdTe层进入,而非经典CdTe电池结构中的CdS层,避免了CdS层对短波段的吸收,提高了短波段光子的响应。添加MoO_x缓冲层后,降低了ITO与CdTe层间的接触势垒,同时,形成了电子反射层,还降低了电子与空穴的复合几率。因此,这一结构不仅提高了电池的短路电流密度(J_(sc)),还将电池的开路电压(V_(oc))提高到了1V以上。在模拟中当MoO_x缓冲层为2nm时,有赖于较理想的ITO功函数和界面复合速率,得到了最高效率达25.5%的超薄CdTe太阳电池。

The software of solar cell capacitance simulator(SCAPS)is used to investigate the performance of ultra-thin CdTe solar cells in the backwall configuration(glass/ITO/MoO/CdTe/CdS/SnO2/Ag).The backwall structure utilizes ultra-thin CdTe absorber layer instead of CdS filmfacing light illumination,which eliminates the absorption of CdS in short-wavelength region and improves the blue response of CdTe.A buffer layer of MoO is added to modify the contact between CdTe and ITO,reducing the valence band barrier height and simultaneously forming an electron reflector,which can reduce electron-hole recombination at this contact.Then,sc is improved and oc can reach 1 V.When the thickness of MoO is 2 nm,the simulation results show that the efficiency can reach up to 25.5%with high ITO work function and ideal interface recombination velocity.