Spray-deposited CuInS₂solar cells

Abstract

Spray deposition of CuInS 2 offers an attractive route towards industrial production of thin-film solar cells. With spray deposition it is possible to make nanocomposites of n-type TiO 2 and p-type CuInS 2 . Upon application of an In 2 S 3 buffer layer, solar cells can be made with efficiencies of ∼7%, being comparable to that of amorphous silicon. Rapid thermal annealing is not involved in the production of these solar cells. In order to further improve the performance, the concentration of electronic defect states in the bandgap must be reduced. Towards this end a detailed study has been undertaken to elucidate the role of associated point defects in the recombination of electron-hole pairs. Especially with transient absorption spectroscopy it is possible to make an accurate assessment of the fundamental electronic processes that are involved. We find electronic states in the bandgap related to the presence of anti-site defects. In addition, indium vacancies are also involved. State-to-state recombination occurs, indicating that the involved defects are associated. An electronic state located at 1.1 eV above the valence band, which is related to indium on a copper position, has a lifetime of about 20 μs at room temperature. The lower lying states related to copper on indium positions, and indium vacancies, are populated from this 1.1 eV state.

Effect of [Cu]/[Cu+In] ratio in the solution bath on the growth and physical properties of CuInS2 film using one-step electrodeposition

“…Various methods have been used to prepare CuInS 2 photoabsorber layers, such as plasma sputtering deposition [12,13], spray pyrolysis [14,15], thermal evaporation [16], chemical bath deposition [1,17], and electrodeposition [18,19]. For industrial applications, electrodeposition is a non-vacuum method for the preparation of ternary semiconductors such as CuInS 2 [20] or CuInSe 2 [21].…”

Extremely thin absorber solar cells based on nanostructured semiconductors

“…49 Under AM 1?5 illumination, the best TiO 2 -CuInS 2 solar cell was produced using spray deposition processing, which had a very high efficiency of 7% (see Table 1). 50 It was also found that these devices gave the same characteristics after several months of storage, indicating that they were stable. 49 Thin film absorbers…”

“…48 CuInS 2 was deposited into the pores of TiO 2 by atomic layer chemical vapour deposition in an earlier study, 48 and later by chemical spray deposition. 49,50 Both methods were chosen because they can produce a conformal coating on a textured substrate. With both methods, an In 2 S 3 buffer layer was added before CuInS 2 coating.…”

Growth and Characterization of Nanocrystalline CuInSSe Thin Films by Spray Pyrolysis

“…CuInS 2 and CuInSe 2 play an important role for thin film solar cell applications having electrical conversion efficiency about 5-12.5 % [1][2][3] and 15.4 % [4] respectively. CuInS 2 has a band gap 1.53 eV, which is higher than the optimum gap of 1.2 eV and CuInSe 2 has a band gap 1.02 eV which is lower than the optimum gap.…”