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The Cu (ln1‐xGax)Se2 (CIGS) solar cell technology is a potentially high‐efficient approach with unique properties compared with silicon photovoltaic, like flexible lightweight substrates and different colored designs. So far, the full potential of the transparent conductive oxide layers has not been exploited yet as no front contacts are applied, resulting in significant losses from the cell‐to‐module level. In this study, Ag front contacts are applied by parallel dispensing onto indium tin oxide layers of silicon heterojunction substrates and CIGS substrates. Subsequently, a thermally curing process is carried out to form the conductive contacts. The curing conditions are varied between 200°C ≥ Tc ≥ 100°C combined with 20 min ≥ tc ≥ 1.5 min. The study aims to determine the curing parameters enabling low‐resistivity contacts by using low‐temperature curing Ag paste and ultralow‐temperature curing Ag paste. The lateral electrode resistance and the contact resistivity of printed electrodes are measured. The results of simultaneous thermogravimetry‐differential scanning calorimetry (pastes) and microstructure analysis of printed electrodes are used to explain the electrical parameters of the printed electrodes. In general, higher curing temperatures and longer curing durations encourage the sintering and densification process of the applied electrodes resulting in low‐resistivity contacts. Contact resistivities below ρc,TLM < 5 mΩ·cm2 and lateral electrode resistance of Rlateral ≥ 17 Ω m−1 are obtained for different paste systems. However, optimal curing conditions of low‐temperature curing pastes can cause thermal damage to the CIGS device. Therefore, ultralow‐temperature curing pastes seem to be promising candidates for front contact metallization of CIGS substrates. [ABSTRACT FROM AUTHOR]

This work focuses on developing an understanding of the rheological properties of polymer-based dopant-source inks at the timescales relevant to inkjet printing and their corresponding roles in determining the production of defect-free droplets. Ink-specific optimization of printing processes for phosphorus and boron dopant-source inks with different compositions is demonstrated. Rheological flow curves measured by a piezo axial vibrator (PAV) were used to study the changes in complex viscosity (η*) and in the elastic (G′) and viscous (G″) components of the shear modulus (G*) with respect to changes in frequency (from fmin = 1 kHz to fmax = 10 kHz) to obtain an insight into the high-frequency behaviour of inks, as well as the effects of temperature (25 °C and 45 °C) and the natural aging time of the inks. Inks demonstrating complex viscosity η*min ≥ 2 mPas to η*max ≤ 20 mPas and an elastic modulus G′ ≤ 20 Pa, produced droplets with negligible defects. Of the three rheological parameters (η*, G′ and G″), the elastic component (G′) of the shear modulus was observed to have the greatest significance in determining the stability and homogeneity of ink droplets, thus dictating the quality of the printed structures. The reliability and stability of droplet formation were further investigated through voltage waveform simulation using an oscilloscope. [ABSTRACT FROM AUTHOR]

The development of new ways of increasing the production throughput for passivated emitter and rear cells (PERCs), as the major solar cell technology in the global market, is an area of great interest to the PV community. This paper presents approaches for significantly increasing the throughput of PERC production processes. The main focus is on the tube furnace processes for the emitter formation and oxidation, with the introduction of the High Temperature Stack Oxidation (HiTSOx) approach. Additional approaches that are currently under investigation at Fraunhofer ISE for increasing the throughput for wet-chemical, printing and laser processes will also be briefly outlined. [ABSTRACT FROM AUTHOR]