1. Institute of Flexible Electronics (IFE) Northwestern Polytechnical University (NPU) Xi'an 710072 China
2. Hoffman Institute of Advanced Materials Shenzhen Polytechnic 7098 Liuxian Boulevard Shenzhen 518055 China
3. Division of Physical Science and Engineering and KAUST Solar Center King Abdullah University of Science and Technology (KAUST) Thuwal 23955‐6900 Saudi Arabia