This paper reports the fabrication of crystalline silicon passivated emitter rear totally diffused (c-Si PERT) solar cells with ultra-thin p-type wafers 50 μm in thickness. Co-diffusion of boron and phosphorus in a single rapid thermal processing cycle, and an Al spin-on glass post-curing process were developed to remove the boron rich layer which is detrimental to c-Si solar cells. Co-diffusion was carried out with spin-on diffusion sources using boric acid and a P spin on dopant for simple and cost-effective emitter and back surface field (BSF) formation processes. The fabricated ultra-thin c-Si PERT cell featured an open circuit voltage (Voc) of 0.575 V, a short circuit current density (Jsc) of 35.8 mA cm-2, a fill factor of 0.725, and a power conversion efficiency of 15.0%. The efficiency has improved by 2% compared with the standard structure cell with Al-BSF using thin evaporated Al 2 μm in thickness. Along with cell output parameters, the flexural strength and critical bending radius were measured by a four point bending test, and the results showed that the solar cells with thinner rear Al electrodes are more applicable for a flexible solar cell device.
Bibliographical noteFunding Information:
This work was supported by the Korea Institute of Science and Technology (KIST), the Korea Institute of Energy Technology Evaluation and Planning (KETEP) (Grant Nos. 20143030011850, 20153030013060, 20163010012580), and the Ministry of Trade, Industry & Energy (MOTIE). I Kim acknowledges KUUC (KIST-UNIST-Ulsan Center for Convergent Materials) for partial financial support.
© 2018 IOP Publishing Ltd.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Acoustics and Ultrasonics
- Surfaces, Coatings and Films