Light Management in Ultra-Thin Cu(In, Ga)Se2 Photovoltaic Devices

• Cu(In, Ga)Se2 (CIGS) solar cells exhibit high conversion efficiencies, with a recent record of 23.35 % on the cell level. However, an absorber thickness >1.8 m is required for efficient absorption of long-wavelength light. In order to minimize the material consumption (In, Ga and other elements) and to accelerate the fabrication process, further thinning down of CIGS absorber layer is important. One of the main challenges of ultra-thin absorber devices is to increase light absorption and consequently the photocurrent. We employ advanced optical simulations of ultra-thin (500 nm) CIGS devices in a PV module configuration, thus solar cell structure including encapsulation and front glass. Using simulations, we design and investigate different solutions for increased short circuit current, in particular (i) highly reflective back reflectors (BR), (ii) internal nano-textures and (iii) external textures by applying a light management foil. We show that any single solution (i, ii, iii) is not enough to compensate for the lower photocurrent, when thinning down (1800 nm -> 500 nm) the absorber layer. A combination of properly optimized internal or external textures and highly reflective back reflector is needed to reach, or even exceed (by ~3-5 %), the short circuit current of a standard thick (1800 nm) CIGS module structure.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Elektroteknik och elektronik -- Annan elektroteknik och elektronik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Electrical Engineering, Electronic Engineering, Information Engineering -- Other Electrical Engineering, Electronic Engineering, Information Engineering (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Naturresursteknik -- Energisystem (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Environmental Engineering -- Energy Systems (hsv//eng)

Nyckelord

Teknisk fysik med inriktning mot elektronik

Engineering Science with specialization in Electronics

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