The graded bandgap of kesterite based absorber layer is an important way to achieve high efficiency solar cells. Incorporation of Ag into CZTSSe thin films can adjust the bandgap and thus reduce the VOC-deficit and im...The graded bandgap of kesterite based absorber layer is an important way to achieve high efficiency solar cells. Incorporation of Ag into CZTSSe thin films can adjust the bandgap and thus reduce the VOC-deficit and improve the quality of crystallization. However, the distribution of Ag is difficult to control due to the quick diffusion of Ag under the high temperature. In this study, we achieve the front Ag-gradient in kesterite structured compound films by prealloying followed by selenization process at 550 °C. AgZn3,Ag3Sn, and Sn–Ag–Cu alloy phases were formed during prealloying stage at 250 °C. After prealloying process, Ag tends to distribute at the front surface of the ACZTSe thin films. Combining the results of experiment and SCAPS simulation, the significantly VOCimprovement of devices is ascribed to the formation of the front Ag-gradient bandgap structure in the absorber layer. This facile prealloying selenization process affords a feasible method to design the graded bandgap structure absorber layers, which will promote the fabrication of high efficient graded bandgap structure solar cells.展开更多
采用磁控溅射Zn-Cu-Sn-Cu金属预置层并后硒化的方法在镀钼玻璃衬底上制备了CZTSe薄膜。利用X射线衍射仪(XRD)、拉曼光谱测试仪(Raman)、扫描电子显微镜(SEM)、能谱仪(EDS)和热探针对所制备CZTSe薄膜的晶相结构、拉曼位移、表面形貌、化...采用磁控溅射Zn-Cu-Sn-Cu金属预置层并后硒化的方法在镀钼玻璃衬底上制备了CZTSe薄膜。利用X射线衍射仪(XRD)、拉曼光谱测试仪(Raman)、扫描电子显微镜(SEM)、能谱仪(EDS)和热探针对所制备CZTSe薄膜的晶相结构、拉曼位移、表面形貌、化学组分和导电类型进行表征分析,分析结果表明:所制备CZTSe薄膜结晶质量好、无二次相、晶粒均匀致密、化学组分是贫铜富锌的,且导电类型为p型,符合高效率太阳电池吸收层的要求。将CZTSe吸收层制备成有效面积为0.35 cm2的Mo/CZTSe/Cd S/i-ZnO/Zn O:Al/Ni-Al电池,其效率为1.17%,开路电压为419 m V,短路电流密度为10.21 m A/cm^2,填充因子为27%。展开更多
The CuZnSn（CZT） precursor thin films are grown by ion-beam sputtering Cu, Zn, Sn targets with different orders and then sputtering Se target to fabricate Cu_2ZnSnSe_4（CZTSe） absorber thin films on molybdenum subst...The CuZnSn（CZT） precursor thin films are grown by ion-beam sputtering Cu, Zn, Sn targets with different orders and then sputtering Se target to fabricate Cu_2ZnSnSe_4（CZTSe） absorber thin films on molybdenum substrates. They are annealed in the same vacuum chamber at 400 ℃. The characterization methods of CZTSe thin films include X-ray diffraction（XRD）, energy dispersive spectroscopy（EDS）, scanning electron microscopy（SEM）, and X-ray photoelectron spectra（XPS） in order to study the crystallographic properties, composition, surface morphology, electrical properties and so on. The results display that the CZTSe thin films got the strongest diffraction peak intensity and were with good crystalline quality and its morphology appeared smooth and compact with a sequence of Cu/Zn/Sn/Se, which reveals that the expected states for CZTSe are Cu^（1＋）, Zn^（2＋）, Sn^（4＋）, Se^（2）.With the good crystalline quality and close to ideal stoichiometric ratio the resistivity of the CZTSe film with the sequence of Cu/Zn/Sn/Se is lower, whose optical band gap is about 1.50 eV.展开更多
Cd-free kesterite structured solar cells are currently attracting attention because they are environmentally friendly. It is reported that Zn(O,S) can be used as a buffer layer in these solar cells. However, the band ...Cd-free kesterite structured solar cells are currently attracting attention because they are environmentally friendly. It is reported that Zn(O,S) can be used as a buffer layer in these solar cells. However, the band alignment is not clear and the carrier concentration of Zn(O,S) layer is low. In this study, the band alignment of the Zn(O,S)/Cu_2 ZnSnSe_4 p–n junction solar cell and the effect of In_2 S_3/Zn(O,S) double buffer layer are studied by numerically simulation with wxAMPS software.By optimizing the band gap structure between Zn(O,S) buffer layer and Cu_2 ZnSnSe_4 absorber layer and enhancing the carrier concentration of Zn(O,S) layer, the device efficiency can be improved greatly. The value of CBO is in a range of 0 eV–0.4 eV for S/(S + O)= 0.6–0.8 in Zn(O,S). The In_2 S_3 is mainly used to increase the carrier concentration when it is used as a buffer layer together with Zn(O,S).展开更多
The objective of this study is to find an effective method to improve Voc without Jsc loss for Cu2ZnSnSe4 （CZTSe） thin film solar cells, which have been fabricated by the one step co-evaporation technique. Surface s...The objective of this study is to find an effective method to improve Voc without Jsc loss for Cu2ZnSnSe4 （CZTSe） thin film solar cells, which have been fabricated by the one step co-evaporation technique. Surface sulfurization of CZTSe thin films is carried out by using one technique that does not utilize toxic H2S gas; a sequential evaporation of SnS after CZTSe deposition and the annealing of CZTSe thin films in selenium vapor. A Cu2ZnSn（S, Se）4 （CZTSSe） thin layer is grown on the surface of the CZTSe thin film after the annealing. The conversion efficiency of the completed device is improved due to the enhancement of Voc, which could be attributed to the formation of a hole-recombination barrier at the surface or the passivation of the surface and grain boundary by S incorporation.展开更多
基金supported by the National Natural Science Foundation of China(51572132,61674082,61774089)Tianjin Natural Science Foundation of Key Project(16JCZDJC30700,18JCZDJC31200)+1 种基金YangFan Innovative and Entrepreneurial Research Team Project(2014YT02N037)111 Project(B16027)
文摘The graded bandgap of kesterite based absorber layer is an important way to achieve high efficiency solar cells. Incorporation of Ag into CZTSSe thin films can adjust the bandgap and thus reduce the VOC-deficit and improve the quality of crystallization. However, the distribution of Ag is difficult to control due to the quick diffusion of Ag under the high temperature. In this study, we achieve the front Ag-gradient in kesterite structured compound films by prealloying followed by selenization process at 550 °C. AgZn3,Ag3Sn, and Sn–Ag–Cu alloy phases were formed during prealloying stage at 250 °C. After prealloying process, Ag tends to distribute at the front surface of the ACZTSe thin films. Combining the results of experiment and SCAPS simulation, the significantly VOCimprovement of devices is ascribed to the formation of the front Ag-gradient bandgap structure in the absorber layer. This facile prealloying selenization process affords a feasible method to design the graded bandgap structure absorber layers, which will promote the fabrication of high efficient graded bandgap structure solar cells.
文摘采用磁控溅射Zn-Cu-Sn-Cu金属预置层并后硒化的方法在镀钼玻璃衬底上制备了CZTSe薄膜。利用X射线衍射仪(XRD)、拉曼光谱测试仪(Raman)、扫描电子显微镜(SEM)、能谱仪(EDS)和热探针对所制备CZTSe薄膜的晶相结构、拉曼位移、表面形貌、化学组分和导电类型进行表征分析,分析结果表明:所制备CZTSe薄膜结晶质量好、无二次相、晶粒均匀致密、化学组分是贫铜富锌的,且导电类型为p型,符合高效率太阳电池吸收层的要求。将CZTSe吸收层制备成有效面积为0.35 cm2的Mo/CZTSe/Cd S/i-ZnO/Zn O:Al/Ni-Al电池,其效率为1.17%,开路电压为419 m V,短路电流密度为10.21 m A/cm^2,填充因子为27%。
基金Project supported by the National Natural Science Foundation of China(No.61404086)the Basical Research Program of Shenzhen(Nos.JCYJ20150324140036866,JCYJ20150324141711581)the Natural Science Foundation of SZU(No.2014017)
文摘The CuZnSn（CZT） precursor thin films are grown by ion-beam sputtering Cu, Zn, Sn targets with different orders and then sputtering Se target to fabricate Cu_2ZnSnSe_4（CZTSe） absorber thin films on molybdenum substrates. They are annealed in the same vacuum chamber at 400 ℃. The characterization methods of CZTSe thin films include X-ray diffraction（XRD）, energy dispersive spectroscopy（EDS）, scanning electron microscopy（SEM）, and X-ray photoelectron spectra（XPS） in order to study the crystallographic properties, composition, surface morphology, electrical properties and so on. The results display that the CZTSe thin films got the strongest diffraction peak intensity and were with good crystalline quality and its morphology appeared smooth and compact with a sequence of Cu/Zn/Sn/Se, which reveals that the expected states for CZTSe are Cu^（1＋）, Zn^（2＋）, Sn^（4＋）, Se^（2）.With the good crystalline quality and close to ideal stoichiometric ratio the resistivity of the CZTSe film with the sequence of Cu/Zn/Sn/Se is lower, whose optical band gap is about 1.50 eV.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51572132,61674082,and 61774089)the National Key Research and Development Program of China(Grant No.2018YFB1500202)+1 种基金the Tianjin Natural Science Foundation of Key Project of China(Grant Nos.16JCZDJC30700and 18JCZDJC31200)the 111 Project,China(Grant No.B16027)
文摘Cd-free kesterite structured solar cells are currently attracting attention because they are environmentally friendly. It is reported that Zn(O,S) can be used as a buffer layer in these solar cells. However, the band alignment is not clear and the carrier concentration of Zn(O,S) layer is low. In this study, the band alignment of the Zn(O,S)/Cu_2 ZnSnSe_4 p–n junction solar cell and the effect of In_2 S_3/Zn(O,S) double buffer layer are studied by numerically simulation with wxAMPS software.By optimizing the band gap structure between Zn(O,S) buffer layer and Cu_2 ZnSnSe_4 absorber layer and enhancing the carrier concentration of Zn(O,S) layer, the device efficiency can be improved greatly. The value of CBO is in a range of 0 eV–0.4 eV for S/(S + O)= 0.6–0.8 in Zn(O,S). The In_2 S_3 is mainly used to increase the carrier concentration when it is used as a buffer layer together with Zn(O,S).
基金Supported by the Specialized Research Fund for the Doctoral Program of Higher Education under Grant No 20120031110039
文摘The objective of this study is to find an effective method to improve Voc without Jsc loss for Cu2ZnSnSe4 （CZTSe） thin film solar cells, which have been fabricated by the one step co-evaporation technique. Surface sulfurization of CZTSe thin films is carried out by using one technique that does not utilize toxic H2S gas; a sequential evaporation of SnS after CZTSe deposition and the annealing of CZTSe thin films in selenium vapor. A Cu2ZnSn（S, Se）4 （CZTSSe） thin layer is grown on the surface of the CZTSe thin film after the annealing. The conversion efficiency of the completed device is improved due to the enhancement of Voc, which could be attributed to the formation of a hole-recombination barrier at the surface or the passivation of the surface and grain boundary by S incorporation.
文摘以金属氯化物(氯化铜、氯化锌、氯化锡)为金属源,二氧化硒为前驱体,乙二醇为溶剂,在不同表面活性剂(PVP、聚氧乙烯月桂醚、聚乙二醇1 000、聚山梨酯80)和不同工艺(制备时间和制备温度)的条件下,采用溶剂热法一步合成六角片状的CZTSe纳米晶体颗粒,并采用X射线衍射仪、紫外可见分光光度计与SEM等手段对CZTSe纳米颗粒的物相、性能、形貌进行表征。实验结果表明,通过加入表面活性剂PVP并控制温度(200℃)和合成时间(30 h)可以取得禁带宽度约为1.5 e V、分布均匀、结构为六方片的晶粒,其与太阳能电池所需的最佳禁带宽度相近,有望在新一代太阳能电池中得到应用和推广。
