Title:	Large Area Monofacial Screen-Printed Rear-Emitter nPERT Cells Approaching 23% Efficiency
Author(s):	L. Tous, J. Chen, P. Choulat, S. Singh, A.S.H. van der Heide, M. Aleman, I. Kuzma-Filipek, J. John, F. Duerinckx, J. Szlufcik
Keywords:	Screen Printing, n-Type, PERT
Topic:	Silicon Cells
Subtopic:	Homojunction Solar Cells
Event:	35th European Photovoltaic Solar Energy Conference and Exhibition
Session:	2BO.3.1
Pages:	354 - 358
ISBN:	3-936338-50-7
Paper DOI:	10.4229/35thEUPVSEC20182018-2BO.3.1
Price:	0,00 EUR
Document(s):	paper

Abstract/Summary:

---

In this paper, we present a simple processing sequence to fabricate large area (244.3 cm2) n-type Czochralski-grown (Cz) monofacial screen-printed rear-emitter Passivated Emitter, Rear Totally diffused (nPERT) cells that can be implemented in production as an upgrade to conventional p-type Cz Passivated Emitter Rear Cell (p- Cz PERC) manufacturing. We use conventional POCl3 and BBr3 tube diffusions, selective n++ laser doping from phosphorous silicate glass (PSG), atomic layer deposited (ALD) Al2O3 emitter passivation, and front and rear screenprinting metallization using commercially available pastes and conventional calendered mesh screens. In a first experiment optimizing rear emitter contact pitch, we achieve average cell energy conversion efficiencies of 22.6±0.1% (internal measurement). In a second experiment implementing fine line double printing (FLDP) and double antireflective coating (DARC), we improve average conversion efficiencies to 22.8±0.1% (internal measurement) with the champion cell measured at 23.03% (externally confirmed). Finally, we identify main loss mechanisms using Free Energy Loss Analysis (FELA) and perform Quokka2D simulations to define a feasible roadmap towards >24% efficiencies.