Optoelectronic Effects of Copper-Indium-Gallium-Sulfur (CIGS2)-Solar Cells Prepared by Three-Stage Co-Evaporation Process Technology

Tzu-Chien Li; Chia-Wen Chang; Chia-Chun Tai; Jyh-Jier Ho; Tung-Po Hsieh; Yung-Tsung Liu; Tsung-Lin Lu

doi:10.3390/mi14091709

Optoelectronic Effects of Copper-Indium-Gallium-Sulfur (CIGS₂)-Solar Cells Prepared by Three-Stage Co-Evaporation Process Technology

Micromachines (Basel). 2023 Aug 31;14(9):1709. doi: 10.3390/mi14091709.

Authors

Tzu-Chien Li¹, Chia-Wen Chang², Chia-Chun Tai¹, Jyh-Jier Ho¹, Tung-Po Hsieh², Yung-Tsung Liu², Tsung-Lin Lu¹

Affiliations

¹ Department of Electrical Engineering, National Taiwan Ocean University, No. 2, Peining Rd., Keelung 20224, Taiwan.
² Photovoltaic Technology Division, Green Energy and Environment Research Laboratories, Industrial Tech Research Institute, No. 195, Sec. 4, Chung-Hsing Rd., Chutung, Hsinchu 310401, Taiwan.

Abstract

In this paper, the performance of Cu-(In,Ga)-S₂ (CIGS₂) solar cells with adjusting composite [Cu]/([Ga] + [In]) (CGI)-ratio absorber was explored and compared through an improved three-stage co-evaporation technique. For co-evaporating CIGS₂ absorber as a less toxic alternative to Cd-containing film, we analyzed the effect of the CGI-ratio stoichiometry and crystallinity, and explored its opto-electric sensing characteristic of individual solar cell. The results of this research signified the potential of high-performance CIGS₂-absorption solar cells for photovoltaic (PV)-module industrial applications. For the optimal CIGS₂-absorption film (CGI = 0.95), the Raman main-phase signal (A1) falls at 291 cm^-1, which was excited by the 532 nm line of Ar⁺-laser. Using photo-luminescence (PL) spectroscopy, the corresponding main-peak bandgaps measured was 1.59 eV at the same CGI-ratio film. Meanwhile, the best conversion efficiency (η = 3.212%) and the average external quantum efficiency (EQE = 51.1% in the visible-wavelength region) of photo-electric properties were achieved for the developed CIGS₂-solar cells (CGI = 0.95). The discoveries of this CIGS₂-absorption PV research provided a new scientific understanding of solar cells. Moreover, this research undeniably contributes to a major advancement towards practical PV-module applications and can help more to build an eco-friendly community.

Keywords: Cu-(In,Ga)-S2 (CIGS2) solar cells; [Cu]/([Ga] + [In]) (CGI)-ratio stoichiometry; eco-friendly community; opto-electric sensing performance; three-stage co-evaporation technique.

Grants and funding

The authors acknowledge financial support from The National Science and Technology Council of R.O.C. under contract No. MOST 108-2221-E-019-054.