What is the principle of CIGS solar cells?

Among various types of solar cells, CIGS solar panels are gradually becoming a research hotspot due to their high curvature, low 

manufacturing cost and good environmental friendliness.

I. Basic structure of CIGS solar cells

CIGS solar cellis a thin-film solar cell based on the co-evaporation of four elements: copper, indium, gallium and selenium (Cu, In, 

Ga, Se). Its basic structure includes the following main parts:

Absorbent Layer: This is the core part of the solar cell, mainly responsible for absorbing sunlight and generating photovoltaic current.

The thickness of the CIGS absorber layer is usually between 1-2 microns, and its material composition can be adjusted according to 

the actual needs in order to optimize the performance.

Buffer layer: Located below the absorber layer, the buffer layer is mainly used to mitigate the difference in thermal expansion coeffic-

ients between the absorber layer and the substrate, in order to prevent the degradation of cell performance caused by temperature 

changes.

Back Electrode: Located at the back of the cell, the main function is to collect and export the photogenerated current.

Substrate: As a support body, the substrate needs to have good thermal conductivity and mechanical strength.

II.Working principle of CIGS solar cell

The working principle of CIGS solar cell is mainly based on Photovoltaic effect. When the sunlight irradiates the CIGS absorber layer, 

the photons interact with the electrons in the material, causing the electrons to jump from the valence band to the conduction band,

thus generating a photovoltaic current. This process can convert solar energy into electricity, realizing the conversion and utilization 

of solar energy.

III.Material Composition and Characteristics of CIGS Solar Cells

The CIGS absorber layer is a semiconductor material co-evaporated with four elements: copper, indium, gallium and selenium. 

These four elements exist in the absorber layer in the form of a continuous solid solution, forming a continuous energy band structure. 

Among them, copper and indium form the conduction band, while gallium and selenium form the valence band. When sunlight hits the 

absorber layer, photons interact with the electrons in the absorber layer, causing the electrons to jump from the valence band to the co-

nduction band, thus generating a photogenerated current.

The forbidden band width of the CIGS absorber layer can be adjusted according to the actual needs in order to optimize the performance. 

Typically, the forbidden band width of a CIGS solar cell is between 1.0 and 1.2 eV, which allows it to absorb sunlight with wavelengths in the 

400-1100 nm range. In addition, CIGS materials have high electron mobility and carrier concentration, which helps to improve the photoel-

ectric conversion efficiency of solar cells.

IV.Manufacturing process of CIGS solar cells

The main process for manufacturing CIGS solar power panels includes the following steps:

Preparation of the substrate: select suitable substrate materials, such as glass, ceramics or metal, and clean and dry them.

Preparation of buffer layer: Prepare a layer of buffer layer material on the substrate using methods such as chemical vapor deposition 

(CVD) or physical vapor deposition (PVD).

Preparation of absorber layer: copper, indium, gallium, selenium, four elements according to a certain proportion of mixing and the 

formation of alloy targets, and then using magnetron sputtering or vacuum evaporation methods such as target evaporation and depos-

ition of the absorber layer on the substrate.

Preparation of back electrode: The back electrode material is prepared on the back of the absorber layer by evaporation or screen printing.

Completion of encapsulation: The prepared solar cell is encapsulated to protect its internal structure and service life. Commonly used en-

capsulation materials include glass, epoxy resin and so on.

Compared with traditional silicon-based solar panels, CIGS solar cells have a low production price and a high sales price, but the degree 

of bending is also high compared to crystalline silicon solar panels on the market