Graded Carrier Concentration Absorber Profile for High Efficiency CIGS Solar Cells

Abstract

We demonstrate an innovative CIGS-based solar cells model with a graded doping concentration absorber profile, capable of achieving high efficiency values. In detail, we start with an in-depth discussion concerning the parametrical study of conventional CIGS solar cells structures. We have used the wxAMPS software in order to numerically simulate cell electrical behaviour. By means of simulations, we have studied the variation of relevant physical and chemical parameters—characteristic of such devices—with changing energy gap and doping density of the absorber layer. Our results show that, in uniform CIGS cell, the efficiency, the open circuit voltage, and short circuit current heavily depend on CIGS band gap. Our numerical analysis highlights that the band gap value of 1.40 eV is optimal, but both the presence of Molybdenum back contact and the high carrier recombination near the junction noticeably reduce the crucial electrical parameters. For the above-mentioned reasons, we have demonstrated that the efficiency obtained by conventional CIGS cells is lower if compared to the values reached by our proposed graded carrier concentration profile structures (up to 21%).

Band Gap and Defect Engineering for High‐Performance Cadmium‐free Sb2(S,Se)3 Solar Cells and Modules

“…In various inorganic thin‐film solar cells, a V‐shaped graded bandgap profile, with larger band gap at the front and back side and a narrow band gap in the middle of the absorber layer, has proven to be an effective means to enhance device performance. [ 11–16 ] High‐performance Cu(In,Ga)Se 2 solar cells are often prepared with a V‐shaped graded bandgap profile, enabled by double Ga grading along the depth of the absorber film. While the front grading generally improves V OC , [ 15 ] the back grading enhances carrier transport and suppresses interface recombination at the back contact.…”

“…[ 11–16 ] High‐performance Cu(In,Ga)Se 2 solar cells are often prepared with a V‐shaped graded bandgap profile, enabled by double Ga grading along the depth of the absorber film. While the front grading generally improves V OC , [ 15 ] the back grading enhances carrier transport and suppresses interface recombination at the back contact. [ 16 ] The V‐shaped graded bandgap profile is also applied in Cu 2 ZnSn(S,Se) 4 (CZTSSe) solar cells, by adjusting the S/(S+Se) ratio in the selenization/sulfurization process.…”

“…In various inorganic thin-film solar cells, a V-shaped graded bandgap profile, with larger band gap at the front and back side and a narrow band gap in the middle of the absorber layer, has proven to be an effective means to enhance device performance. [11][12][13][14][15][16] High-performance Cu(In,Ga)Se 2 solar cells…”

Growth and Characterization of Cu2MnSnS4 Thin Films Synthesized by Spray Pyrolysis under Air Atmosphere

“…Solar energy is one of the most important demand of today. A standard photovoltaic device consists in a films stack, from bottom to the top: a Mo back contact layer (~0.5-1 µm), a thick p-type absorber (~1-2.5 µm), thin n-type buffer layer (~0.1 µm), and a transparent conductive oxide contact layer (<~0.5 µm) [1]. The electrical contacts on the top and on the back are necessary to harvest the electrical charges generated by the adsorption of photons.…”

Cogging torque comparison of Interior Permanent Magnet Synchronous Generators with different stator windings

“…Over the last decades the adequate use of renewable energy resources towards a sustainable development has been one of the most important issues faced by the scientific community [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. In this context, Permanent Magnet Synchronous Machines have acquired great significance in the field of electrical drives and renewable energies, especially because of their great advantages in comparison with machines of the traditional type [17].…”