The average solar buyer probably isn’t paying attention to whether solar panels are made with p-type or n-type solar cells. There are more important things to worry about, like power output and aesthetics. But in case anyone was wondering what those letters mean and how they may affect solar panel buying in the future, here’s a crash course on the science behind solar cells.
First, a conventional crystalline silicon (c-Si) solar cell is a silicon wafer doped with various chemicals to encourage power production. The main difference between p-type and n-type solar cells is the number of electrons. A p-type cell usually dopes its silicon wafer with boron, which has one less electron than silicon (making the cell positively charged). An n-type cell is doped with phosphorus, which has one more electron than silicon (making the cell negatively charged).
The market share of p-type and n-type solar cell designs. Credit: ITRPV
Although the first solar cell invented by Bell Labs in 1954 was n-type, the p-type structure became more dominant due to demand for solar technologies in space. P-type cells proved to be more resistant to space radiation and degradation. Since so much research was thrown into space-related solar technology, it was only natural that p-type cell dominance trickled down to the residential solar market.
But more solar manufacturers are adopting n-type structures because of their additional benefits. For one, since n-type cells use phosphorus instead of boron, they are immune to boron-oxygen defects, which cause decreased efficiency and purity in p-type structures. N-type cells are in turn more efficient and are not affected by light-induced degradation (LID).
The International Technology Roadmap for Photovoltaic (ITRPV) predicts that the market share of p-type mono-c-Si will hold around 30% through 2028, while n-type mono-c-Si will increase to about 28% from barely 5% in 2017. This correlates to the industry demand for more high-efficiency modules, so solar buyers can expect more n-type designs entering the mainstream.
The R&D behind both cell types is strong. While n-type solar cells may be more efficient at a surface-level, outputs on both types can be similar. Some examples to compare:
This June, REC released its N-Peak panel, a 60-cell n-type mono-c-Si module with half-cut cells rated at 330 W. In April, LONGi reached a record with its 60-cell p-type PERC mono-c-Si module with half-cut cells rated at 360 W.
Last May, Trina Solar hit 24.13% efficiency with its n-type mono-c-Si solar cell. This May, JinkoSolar hit a record-breaking 23.95% efficiency with its p-type mono-c-Si solar cell.
P or N type panels never mattered to me before and now I wonder whether they influence the charge converter options that are available to me. Will the power only come out of the panel as positive regardless of polarity of the crystal pieces? I figured this read would make decisions easier but I’m an end user and not a trained electrician or electronics tech.
Hi Xepshunall, I see that no one has replied so perhaps I can help you. There is no difference in any solar installation between using P or N type panels. Power is generated regardless and when connecting up a string of panels to your inverter you must still connect the positive output lead ( of the series string of panels) to the positive input terminal of the inverter and likewise with the negative lead of the string of panels, it is connected to the negative input terminal. Historically ( a long time ago!) it was originally promoted / understood that current flowed from a positive terminal to a negative terminal…however it is factually correct that current flow ( free electrons from a source eg. a battery, or a solar panel etc., flows from the negative terminal to the positive terminal ( through what ever load is between them…an inverter, a light bulb, etc.).
what is the bandgap energy of Boronphosphorus (BP) semiconductor?
Nicely explained!!
Thanks.
The Advantage of the n-type cell is better realized in the bi-facial modules. the continued demand of bifacial modules will increase the n-type share further.
could you explain why do you think so?
what about solar cells made from N-type and P-type at the same time.
All solar cells have both n type and p type with the great majority having one surface n type and one surface p type . It is the junction between the n and the p type regions that creates the step in the energy levels that leads, when illuminated, to the 600 mV potential difference between the electrons entering the p type layer and leaving the n type layer.
The difference between the two types of cell is that in one sort, The crystal is grown from a melt containing a small amount of boron to produce a n type ingot. This is sliced up and phosphorus is diffused in from one side. When the phosphorus concentration exceeds the boron concentration it becomes p-type. The other sort of cell reverses this process. The ingot is grown p type from the melt and one surface is converted to n type by diffusing in boron
Thanks, even more explanation, that’s great! This article was solid, and the comments have been helpful, too, really appreciate it.
Let’s read last line , you have said n- type by diffusion in boron, boron is tri valent then how is this come to n-type. rectify plz
Informative material indeed. Thank you.
Thank you very much for clear information but I have one doubt about Trina Solar that their efficiency 24.13% in N type mono I think jolly wood being the Biggest in china N type cell manufacturers and having Strong Teame Rand D they didnt reach event 23 at this time . can you please double check the information and provide us with the details
thank you
Amazing – thank you !
Cheers
Amazing – thank you ! A very interesting information. I was not aware of it !
Cheers
Very good information it did inlight me. I was not aware of this.