A group of researchers in China have fabricated a heterojunction (HJT) solar cell based on an indium tin oxide (ITO) buffer layer with the aim of improving the device's optical and electrical properties.
“High-power prepared indium tin oxide (ITO) layers have made significant contributions to enhancing the crystal quality of films and the capacity of silicon heterojunction solar cells,” the research's corresponding author, Daxue Du, told pv magazine. “However, it generally causes sputtering damage, resulting in degradation of photovoltaic performance. In this work, we designed an ITO buffer layer on industrial SHJ solar cells and discussed the optical and electrical performance in detail using the monolayer ITO film as a baseline.”
The scientists built the cell with a 120 μm n-type monocrystalline silicon wafer measuring 182 mm × 105 mm, with the hydrogenated
amorphous and microcrystalline silicon passivation films being passivated via plasma-enhanced chemical vapor deposition (PECVD) and the ITO layer being deposited through physical vapor deposition (PVD). Silver grids were manufactured via screen-printing and annealed at 200 C.
“The bilayer ITO was specifically designed to achieve improved electrical performance in the thin buffer layer prepared at low power and O2 concentration, while also enhancing optical performance in the thicker outer layer prepared at higher power and O2 concentration,” the group explained. ” It was designed to obtain smaller refractive indices and smaller extinction coefficients, resulting in higher short-circuit current generation.”
Tested under standard illumination conditions, the cell achieved a power conversion efficiency of 25.36 %, which the scientists said is 0.1% more than that of devices without the ITO buffer layer. Both carrier concentration and carrier mobility were enhanced due to the decrease of chemisorbed oxygen and the increase of oxygen vacancies, respectively, which leads to lower resistivity and higher fill factor.
“We believe that the present work demonstrates a potentially viable approach for high yield and high efficiency of industrial silicon heterojunction solar cells,” Du concluded.
The new solar cell concept was described in the study “Optimized optical and electrical properties for silicon heterojunction solar cells with an indium tin oxide buffer layer,” which was recently published in Solar Energy Materials and Solar Cells. The research team comprised academics from Chinese startup Shanghai Hency Solar Technology and Shanghai Jiao Tong University.
Other researchers at Shanghai Jiao Tong University recently evaluated the impact of gettering in the manufacturing of heterojunction (HJT) solar cell technologies.
This content is protected by copyright and may not be reused. If you want to cooperate with us and would like to reuse some of our content, please contact: editors@pv-magazine.com.
By submitting this form you agree to pv magazine using your data for the purposes of publishing your comment.
Your personal data will only be disclosed or otherwise transmitted to third parties for the purposes of spam filtering or if this is necessary for technical maintenance of the website. Any other transfer to third parties will not take place unless this is justified on the basis of applicable data protection regulations or if pv magazine is legally obliged to do so.
You may revoke this consent at any time with effect for the future, in which case your personal data will be deleted immediately. Otherwise, your data will be deleted if pv magazine has processed your request or the purpose of data storage is fulfilled.
Further information on data privacy can be found in our Data Protection Policy.