Panagiota Arnou

Hydrazine-Free Solution-Deposited CuIn(S,Se)2 Solar Cells by Spray Deposition of Metal Chalcogenides

Solution processing of semiconductors, such as CuInSe2 and its alloys (CIGS), can significantly reduce the manufacturing costs of thin film solar cells. Despite the recent success of solution deposition approaches for CIGS, toxic reagents such as hydrazine are usually involved, which introduce health and safety concerns. Here, we present a simple and safer methodology for the preparation of high-quality CuIn(S, Se)2 absorbers from metal sulfide solutions in a diamine/dithiol mixture. The solutions are sprayed in air, using a chromatography atomizer, followed by a postdeposition selenization step. Two different selenization methods are explored resulting in power conversion efficiencies of up to 8%.

Aluminium-doped zinc oxide deposited by ultrasonic spray pyrolysis for thin film solar cell applications

Aluminum-doped zinc oxide (AZO) thin films were deposited on glass substrates by ultrasonic spray pyrolysis, from metal salt precursors. The electrical and optical properties were investigated as a function of the deposition parameters and the optimum conditions were defined. The thin films exhibit ~80% transparency and a resistivity in the order of 2×10-2Ωcm. The electrical properties can be improved further with post-deposition annealing in vacuum, or with increase in thickness which causes insignificant transmission losses. AZO nanoparticles can be used as a seed layer and affect the optical properties of the material. The optimized process results in good quality AZO films for their application as the transparent conductive oxide (TCO) layer in thin film solar cells.

Solution-deposited CuIn(S,Se)2 absorber layers from metal chalcogenides

CuIn(S,Se)2 (CISS) thin films were deposited using metal chalcogenide precursor solutions. This process involves the dissolution of metal chalcogenides in a solvent combination comprised of ethylenediamine and ethanedithiol and it serves as a safer alternative to the hydrazine-based approach. The characterization of the deposited material verifies the presence of the CISS chalcopyrite phase with good crystal growth. CISS devices were completed in a glass/Mo/CISS/CdS/i-ZnO/AZO configuration with power conversion efficiencies of 6%. The use of a safer solvent mixture and the avoidance of a complicated precursor synthesis can potentially result in a feasible and industrially scalable deposition methodology for CIGS.

High-Efficiency Nanoparticle Solution-Processed Cu(In,Ga)(S,Se) 2 Solar Cells

Thin film Cu(In,Ga)(S,Se)2-based (generally referred to as CIGS) solar cells represent a promising alternative to conventional crystalline silicon solar cells due to their high efficiencies, reduced cost, and better material utilization. In recent years, it has been demonstrated that it is possible to form thin films by annealing nanoparticulate material such that the nanoparticles coalesce to form large grained thin films. In this paper, we present a 13.8% efficient CIGS solar cell derived from printed nanoparticle inks. The approach was successfully extended to fabricate monolithic devices on larger substrates. These results demonstrate that low-cost, nonvacuum printing of CIGS nanoparticles has great potential to achieve high efficiencies and reduce the performance gap with the more traditional vacuum co-evaporation and sputtering techniques.

Analysis and comparison of different selenization routes for nanoparticle ink deposited Cu(In 1−x Ga x )(Se y S 1−y ) 2 solar cells

This paper investigates the effect of using different selenization sources, namely elemental Se and H2Se, on Cu(In1-xGax)(SeyS1-y)2 devices derived from depositions of nanoparticle inks. Nanoparticles used in this synthesis are chalcogenides (e.g. CuInGaS). The effect of the selenization species has a large effect on the performance and electrical properties of these devices. Elemental selenized devices show higher efficiencies (>16%) compared to H2Se processed devices (<;12%). Various techniques are used in this study, including Raman spectroscopy, TEM, I-V-T, EQE, admittance spectroscopy and C-V-T to identify the difference in performance between the two selenization methods. Differences are observed in both the bulk and interface properties of the devices.