Cell Processing

This paper provides a short overview of historical developments, presents the main approaches in mass production today, discusses potential process simplifications, and briefly touches upon a key topic for the future, namely reducing the silver (Ag) consumption per cell.

This paper presents preliminary results of SERIS’ biPolyTM cell: the bifacial application of polysiliconbased passivating contact stacks with front and rear screen-printed and fired metallization.

This work reports the latest results obtained at Jolywood for full-area (251.99cm2) n-type bifacial passivating-contact solar cells using a cost-effective process with industrially-feasible boron diffusion, phosphorus ion implantation and low-pressure chemical vapour deposition (LPCVD) with in situ oxidation.

This paper reviews the key technology improvements which have enabled a continuous 0.5%abs/year increase in efficiency of industrial PERC and PERC+ cells.

Silicon heterojunction (SHJ) solar cell technology is an attractive technology for large-scale production of solar cells with a high conversion efficiency beyond 24%. One key element of SHJ solar cells, contrasting with today’s widespread passivated emitter and rear contact (PERC) cell technology, is the use of transparent conductive oxide (TCO), which poses challenges in performance and costs but also presents opportunities. This paper discusses these aspects and shows the potential for improving cell efficiency at reduced cost by using new TCOs deposited by direct current (DC) sputtering.

In this paper the situation of solar cell production in China is summarized, and an attempt is made to answer the question of whether passivated contacts could replace PERC technology, which will eventually reach its efficiency limit in the future.

Passivated-contact solar cell designs, such as TOPCon or silicon heterojunction solar cells (SHJs), enable cell efficiencies greater than 24%, and are promising candidates for the next revolution in mass production after the passivated emitter and rear cell (PERC). Plated metallization (Ni/Cu/Ag or Cu/Ag) fits well with new constraints on low-temperature processing and the combination of low material costs and highly conductive bifacial metal grids for these types of solar cell.

For the work reported in this paper, a new model of the screen-printing process was set up in order to improve the understanding of the screenprinting process, with a focus on the interaction between Ag paste and the screen.

Organic/inorganic lead halide perovskite solar cells (PSCs) have received global attention because of their excellent photovoltaic performance and ease of fabrication. PSC’s have reached over 24% power conversion efficiency demonstrating that the lead halide perovskites are the most promising class of materials for next-generation thin-film photovoltaics. The unprecedented increase in the device performance from 3.8% to 24% in less than 10 years is mostly due to compositional engineering of mixed cations, and anions, as well as improved processing protocols has made PSC the fastest development of a new material in the PV field. Though the efficiencies on Lab scale are staggering, the full potential of this burgeoning technology cannot be realized without addressing the following challenges: fighting the degradation of the material is the highest focus for the moment and has several fronts for improvements including within larger scale cells or modules. The other main challenge of the new class of material is the toxicity risks due to the presence of lead. The research community is actively working on the mitigation and reduction of the associated risks. The exceptional properties of this material combined alongside its inherent relative lower costs have already triggered the interests of industries and start-up worldwide while on a European regional level, EPKI for European Perovskite Initiative was formed gathering all the significant players in the field.

This paper presents the calibration of solar cells, in accordance with the IEC 60904 standards, carried out at the solar cell calibration laboratory of the Calibration and Test Center (CalTeC) at the Institute of Solar Energy Research Hamelin (ISFH). For the calibration of a solar cell, the cell area, the spectral responsivity (SR) and the current–voltage (I–V) curve have to be determined. The I–V curve then yields the characteristic parameters, including the power conversion efficiency, fill factor, short-circuit current and opencircuit voltage. The required measurement facilities and contacting stages are explained in detail; in addition, the measurement procedures are introduced. The precision and accuracy of the resulting characteristic parameters and curves are demonstrated by recent intercomparisons between different international calibration laboratories.