CZTSe/Cd1-xZnxS界面能带结构研究

严重的开路电压损耗是限制铜锌锡硫(硒)薄膜太阳电池性能提升的关键问题,其吸收层和缓冲层界面的能带结构有待进一步优化.针对此问题,本文对CZTSe/Cd1-xZnxS界面的能带结构进行了研究.首先,模拟计算了化学水浴法制备Cd1-xZnxS薄膜所需的溶液体系条件,通过椭偏仪和SEM测试结果分析了不同Cd/Zn比例的Cd1-xZnxS缓冲层形貌、光学特性以及禁带宽度.然后,对CZTSe/Cd1-xZnxS界面进行了XPS测试分析,发现CZTSe/Cd0.9Zn01S界面最为匹配,其导带失调值约为0.3 eV.最后对电池器件进行了制备与测试,得到的CZTSe/Cd0.9Zn0.1S结构的太阳电池比CZTSe/CdS结构具有更高的开路电压,达到了394 mV,转换效率达到了5.78;.     

衬底温度对共蒸发法制备Cu2ZnSnSe4太阳电池的影响

采用共蒸发法在不同衬底温度下沉积Cu_2ZnSnSe_4(简称CZTSe)薄膜,分析了衬底温度对CZTSe材料性质及电池性能的影响。研究表明:当衬底温度较低时(380℃),CZTSe薄膜中含有SnSe_x使电池失效;随着衬底温度的升高,CZTSe薄膜的结晶质量明显提升,电池开路电压增加。但当衬底温度达到460℃时,电池的转换效率反而下降;结合CZTSe的生长机理及器件模型分析了电池效率下降可能的原因。最终在衬底温度420℃的条件下制备出效率为3.12%(有效面积0.34 cm~2)的CZTSe太阳电池。     

铜蒸发温度对共蒸发法制备Cu2ZnSnSe4太阳电池的影响

由于Cu元素的含量对Cu2ZnSnSe4(CZTSe)化合物的薄膜性质及电池性能都有影响,本文主要研究了不同铜蒸发温度对CZTSe薄膜性质及电池性能的影响.研究表明:当铜蒸发温度较低时(1400 ℃),CZTSe薄膜中含有SnSe相,同时薄膜呈N型;随着铜蒸发温度的提高,CZTSe薄膜的结晶质量明显提升.但当铜蒸发温度过高时(1500 ℃),薄膜中含有CuxSey相.二次相SnSe与CuxSey的存在都会使电池失效.最终通过优化铜的蒸发温度,在较合适的1450 ℃ 铜蒸发温度条件下制备出效率为2.63;(有效面积0.34 cm2)的CZTSe太阳电池.     

Preparation and Characterization of Thin-Film Solar Cells with Ag/C60/MAPbI3/CZTSe/Mo/FTO Multilayered Structures

New solar cells with Ag/C₆₀/MAPbI₃/Cu₂ZnSnSe₄ (CZTSe)/Mo/FTO multilayered structures on glass substrates have been prepared and investigated in this study. The electron-transport layer, active photovoltaic layer, and hole-transport layer were made of C₆₀, CH₃NH₃PbI₃ (MAPbI₃) perovskite, and CZTSe, respectively. The CZTSe hole-transport layers were deposited by magnetic sputtering, with the various thermal annealing temperatures at 300 °C, 400 °C, and 500 °C, and the film thickness was also varied at 50~300 nm The active photovoltaic MAPbI₃ films were prepared using a two-step spin-coating method on the CZTSe hole-transport layers. It has been revealed that the crystalline structure and domain size of the MAPbI₃ perovskite films could be substantially improved. Finally, n-type C₆₀ was vacuum-evaporated to be the electronic transport layer. The 50 nm C₆₀ thin film, in conjunction with 100 nm Ag electrode layer, provided adequate electron current transport in the multilayered structures. The solar cell current density–voltage characteristics were evaluated and compared with the thin-film microstructures. The photo-electronic power-conversion efficiency could be improved to 14.2% when the annealing temperature was 500 °C and the film thickness was 200 nm. The thin-film solar cell characteristics of open-circuit voltage, short-circuit current density, fill factor, series-resistance, and Pmax were found to be 1.07 V, 19.69 mA/cm², 67.39%, 18.5 Ω and 1.42 mW, respectively.     

沉积时间对Zn(O,S)薄膜性能及Cu2ZnSnSe4薄膜电池的影响

无镉材料Zn(O,S)因其带隙宽且可调节、无毒无害等优点被作为缓冲层材料重点研究,通过化学水浴法制备Zn(O,S)薄膜,研究了沉积时间的不同(20~35 min)对Zn(O,S)薄膜的成分、结构特性、光学性能及形貌的影响.通过XRD测试可知,水浴法制备的Zn(O,S)薄膜为非晶态.通过透反射谱测试可知,薄膜的光学透过率较高(>80;).通过表面形貌测试可知,30 min时Zn(O,S)薄膜为致密均匀的小颗粒.将Zn(O,S)薄膜应用在CZTSe电池中,在30 min时获得较高器件转换效率5.37;.