1. IEK-5 Photovoltaik, Forschungszentrum Jülich, 52428, Jülich, Germany
2. School of Physics, Sun Yat-Sen University, Guangzhou, 510275, PR China
3. Helmholtz Nano Facility, Forschungszentrum Jülich, 52428, Jülich, Germany
4. Institute for Solar Energy Systems, Guangdong Provincial Key Laboratory of Photovoltaic Technology, Sun Yat-Sen University, 510006 Guangzhou, China
5. State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-Sen University, Guangzhou, Guangdong Province PR China