A workforce together with scientists from the Insititute for Solar Energy Research Hamelin (ISFH) and German PV tools producer Centrotherm has developed a POLO again junction photo voltaic cell through the use of industrial plasma enhanced chemical vapor deposition (PECVD) which system with a low-frequency plasma supply. The system achieves a barely greater effectivity than a reference system made by costlier atomic layer deposition (ALD).
A gaggle of researchers led by Germany’s Insititute for Solar Energy Research Hamelin (ISFH) developed a n+-type polysilicon on oxide (POLO) again junction photo voltaic cell with a passivation layer stack based mostly on aluminum oxide (AlOx) and silicon nitride (SiNy).
“Our examine exhibits for the primary time an efficient industrial cleansing and adjustment for untextured entrance surfaces with glorious adjustment high quality,” the lead writer of the analysis, Byungsul Min , stated. pv journal. In explicit, AlOx/SiNy The passivation layer stack is manufactured in an industrial improved plasma chemical vapor deposition (PECVD) techniques with low-frequency (LF) plasma sources are cheaper than atomic layer deposition (ALD) techniques or PECVD techniques with high-frequency (HF) plasma sources.
The novel cell know-how is launched within the paper “24.2% environment friendly POLO again junction photo voltaic cell with AlOx/SiNy dielectric stack from an industrial-scale direct plasma-enhanced chemical vapor deposition system,” revealed in Advances in Photovoltaics. “Our outcomes present a path for the industrialization of recent cell ideas with out entrance facet diffusion like our POLO again junction photo voltaic cell, however they’re additionally related for a mainstream idea like at TOPCon utilizing the primary ALD system for his or her AlOx layer.”
The group constructed a 156.75 mm x 156.75 mm POLO cell with a gallium-doped Czochralski-grown silicon wafer with a resistivity of 0.73 Ωcm. To deposit the AlOx layer it used an industrial batch-type LF-PECVD system offered by German PV tools producer Centrotherm, whose researchers additionally contributed to the analysis. “We tailored the recipe by various the thickness of the silicon oxide (SiO2) layer below the AlOx layer between 0 and a pair of nm, the thickness of the AlOx layer between 5 and 15 nm which thickness, and the refractive index of the SiNy layer is between 2.05 and a pair of.4,” defined the researchers.
They additionally produced a reference system based mostly on a textured gallium-doped Czochralski-grown wafer with a resistivity of 0.9 Ωcm passivated utilizing a 10-nm-thick AlOx layer deposited by ALD and a SiN y layer. “After display printing the aluminum grid on the entrance and silver grid on the again, the samples had been co-fired in a belt furnace at a peak firing temperature between 800 C and 810 C,” they additional defined. .
Tested below customary lighting circumstances, the POLO cell achieved an influence conversion effectivity of 24.2%, an open-circuit voltage of 725 mV, a short-circuit present density of 40.2 mA/ cm2, and a fill issue of 83.0%, with the outcomes. which is confirmed by ISFH CalTeC. The benchmark system achieved an effectivity of 24.1% an open circuit voltage of 725 mV, a brief circuit density of 39.9 mA/cm2, and a fill issue of 83.2%.
“The integration of this passivation sequence into our present course of movement for POLO BJ photo voltaic cells has been efficiently demonstrated in POLO BJ photo voltaic cells, which present greater cell efficiencies than the reference lab-scale fabrication of processes,” the researchers concluded.
Image: Institute for Solar Energy Research Hamelin (ISFH)
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