Dr. Xixiang Xu is deputy director of LONGi Central Research Institute. He made his first solar cell in 1981 during his senior studies at Lanzhou University, in an amorphous silicon (a-Si) pin structure. He continued his graduate research in Prof. Chen’s group, and finally obtained 4.08% cell efficiency (related work published in 1st PVSEC, Kobe, Japan, 1984).

In 1987, Xixiang started his Ph.D. study under guidance of Prof. Tatsuo Shimizu, at Kanazawa University, Japan, focusing on defects and their meta-stability in wide bandgap a-Si alloy films. In 1990, he joined Prof. Sigurd Wagner’s group at Princeton as a postdoc and studied narrow bandgap a-Si based alloys, such as a-SiGex:H films and their applications in PV.

Dr. Xu started working in PV industry in 1991 at USSC, a joint venture between Energy Conversion Devices, USA, and Canon, Japan. His main effort was on developing high quality a-Si alloy films using RF, VHF, and MW excited PECVD and fabricating tandem solar cells. After a tenure at Intel to work on Si process development, Dr. Xu rejoined Uni-Solar, where he led a team to work on large-area tandem junction solar cells and achieved multiple cell efficiency world records on both double- and triple-junction cell structures.

In 2010, Dr. Xu joined Apollo/Hanergy Solar as a co-CTO with Dr. Yuanmin Li. They co-founded Chengdu R&D Center in 2011, and worked on several thin film PV technologies, including a-Si:H, a-SiGe, nc-Si:H, and perovskite. In 2014, they initiated work on silicon heterojunction (SHJ) solar cell, and achieved 25.11% record efficiency in 2019.

Dr. Xu joined LONGi Solar in early 2020 and led SHJ and tandem cell technology development. Though the lab construction was delayed by COVID, the team developed superior a-Si:H & nc-SiOx:H films and further optimized TCO. Within 10 months, the team had obtained 4 new world records, and increased SHJ cell efficiency from 25.11% to 26.30%, which is a highest efficiency obtained on a full size Si wafer (274.5 cm^2, total area).