Over the last few years, there has been somewhat of an explosion in new solar technology, with next-generation panels featuring a variety of advanced PV cell designs and innovations that help boost efficiency, reduce degradation, and improve reliability. While some of the recent advancements, including micro-busbars and gapless cell architectures, have been adopted by many manufacturers, other innovations and combinations are new. In this article, we explain how these new solar cell technologies increase efficiency, improve overall performance and increase the lifespan of a solar panel.

Latest Solar PV Cell Technology

Most panel manufacturers offer a range of models, including regular entry-level options and more advanced high-efficiency varieties featuring new technologies such as high-density cells, micro-wire busbars and rear-side passivation. Below is a list of the leading PV cell technologies used today:

HJT - Heterojunction cells
TOPCon - Tunnel Oxide Passivated Contact
Gapless Cells - High-density cell construction
Multi Busbar - Multi ribbon and micro-wire busbars
Split cells - half-cut and 1/3 cut cells
Shingled Cells - Multiple overlapping cells
IBC - Interdigitated Back Contact cells

These innovations, and more explained in detail below, offer various efficiency improvements, shade tolerance, and increased reliability. Many manufacturers offer up to 25-year product warranties and 25- to 30-year performance warranties. However, with all the new panel varieties available, it is worth doing some research before you invest in a solar installation. In our quality solar panel review article, we explain how to select a reliable solar panel and further highlight the best quality manufacturers on the market.

Solar panels featuring the latest cell technologies

Below is our list of panels featuring the latest advancements in PV technology rated according to the cell technology, efficiency improvements, performance, and innovations. For the most efficient solar panels, see our detailed solar panel efficiency review.

Make	Leading Model*	Cell Type	Cell Technology*	Max Efficiency*
Aiko	Black Hole Series	N-type	Half-cut Back-Contact 18BB	23.8%
REC	Alpha Pure RX	N-type	Half-cut HJT lead-free Gapless 20BB	22.6%
SPIC	Andromeda 3.0	N-type	Half-cut IBC-TOPcon MBB Gapless	22.8%
Longi Solar	Hi-MO 6 Scientist	N-type	Half-cut Hybrid Back-Contact MBB	23.0%
Trina Solar	Vertex S+	P-type	Half-cut TOPcon MBB	22.5%
JinkoSolar	Tiger NEO	N-type	Half-cut TOPcon Gapless	22.5%
Panasonic	EverVolt H	N-type	Half-cut HJT MBB	22.2%
Canadian Solar	CS6R-H-AG	N-type	Half-cut HJT MBB	22.5%
Futura Sun	FU 360M Zebra	N-type	IBC MBB Half-cut	21.3%

* Leading model using the most advanced PV cells currently offered by the manufacturer

HJT = Heterojunction cells, MBB = Multi busbars, Gapless = High-denisty cells, Ga-doped = Gallium doped silicon

Learn about the difference between N-type and P-type solar cells here.

Solar Panel Efficiency

Solar panel efficiency is one of several important factors and is dependent upon both the PV cell type and panel technology. Average panel efficiency has increased considerably over recent years from around 16% to well above 22% as manufacturers incorporate the latest cell technologies and innovations.

At present, the world's most efficient solar panels are manufactured using HJT and IBC N-type monocrystalline silicon cells and achieve efficiency levels above 22.5%. While HJT and IBC N-type cells are more expensive to manufacture, the higher upfront cost is outweighed by the increased efficiency, improved performance at higher temperatures and minimal light-induced degradation (LID), which means much higher energy yield over the life of the panel.

Sunpower, Aiko, SPIC and Recom are currently the leading manufacturers using IBC cells. However, the latest panels from REC, Longi, Huasun, Panasonic, Trina and Canadian Solar utilise very efficient N-type heterojunction (HJT) and TOPCon cells. Panels featuring HJT cells offer an extremely low power temperature co-efficient, which means they can outperform even IBC cells under certain conditions. See the complete list of the most efficient solar panels.

High-Temperature Performance

The power temperature coefficient is the amount of power loss as cell temperature increases. All solar cells and panels are rated using standard test conditions (STC - measured at 25°C) and slowly reduce power output as cell temperature increases. Generally, the cell temperature is 20-35°C higher than the ambient air temperature, which equates to an 8-14% reduction in power output.

Power temperature coefficient comparison - Lower is more efficient

Polycrystalline P-type cells - 0.4 to 0.43 % /°C
Monocrystalline P-Type cells - 0.35 to 0.40 % /°C
Monocrystalline N-type TOPcon cells - 0.30 to 0.34 % /°C
Monocrystalline N-type IBC cells - 0.27 to 0.31 % /°C
Monocrystalline N-type HJT cells - 0.25 to 0.27 % /°C

Monocrystalline N-type cells such as TOPcon, which are now widely used by many leading manufacturers, have an improved temperature coefficient compared to traditional Mono and Poly P-type cells used for much of the last decade. Monocrystalline IBC or Interdigitated Back Contact cells, described in more detail below, have a much lower temperature coefficient of -0.30% /°C compared to standard polycrystalline and monocrystalline cells. However, the best-performing cells at elevated temperatures are the heterojunction (HJT) cells, such as those from Panasonic and REC, which we describe in the last section of this article.

PERC - Passivated cells

PERC cells were the dominant cell technology used worldwide from around 2017 to 2022 and only recently became superseded by more efficient N-type TOPcon and IBC cells. The director of the Australian Centre for Advanced Photovoltaics at UNSW, Professor Martin Green, invented the PERC concept in the 1980s, but it took decades before the manufacturing technology was available to produce PERC cells on a mass scale. PERC stands for 'Passivated Emitter and Rear Cell', which uses additional layers on the rear side of the cell to absorb more light photons and increase total 'quantum efficiency'. A common PERC technology is the local Al-BSF or local Aluminium Back Surface Field (see diagram below). However, several other variations were developed, such as PERT (passivated emitter rear totally diffused) and PERL (Passivated Emitter and Rear Locally-diffused).

The PERC rear layer and local AI-BSF (Aluminum Back Surface Field) - Image credit LONGi Solar

Multiple Busbars - MBB

Small silver metallic fingers across each cell transfer current to the busbars. More recently, many manufacturers have moved from traditional ribbon busbars to multiple-wire busbars or MBB.

Busbars are thin wires or ribbons which run down each cell and are visible on most solar panels. Busbars perform two main functions, they collect the electrons from the small metallic fingers on the cell surface, and interconnect the front of the cell to the rear side of the adjacent cell creating a circuit throughout the panel. As PV cells became more efficient they generated more current and over recent years most manufacturers moved from 4 or 5 standard ribbon busbars to 9 or more multi-busbars (MBB). Some larger format cells, such as the 210mm cells developed by Trina Solar, have 12 busbars while the REC Alpha range has an impressive 16 micro busbars.

Multi-busbar compared to a standard ribbon busbar - Image credit Trina Solar (click to enlarge) — Multi-busbar compared to a standard ribbon busbar - Image credit Trina Solar

An additional benefit of more busbars is if a cell micro-crack occurs due to impact, heavy loads or people walking on panels, more busbars help reduce the chance of the crack/s developing into a hot spot as they provide alternative paths for current to flow.

LG was the first manufacturer to use round micro-wire busbars on the Neon 2 range of panels. LG called this 'Cello' technology which stands for 'cell connection, electrically low loss, low stress and optical absorption enhancement'. To translate, the Cello multi-wire technology lowers electrical resistance and increases efficiency.

Split Modules with Half-Cut Cells

Over the last few years, most leading manufacturer’s have shifted to using half-cut or half-size cells rather than the traditional full-size square cells. The square cells are laser cut in half and assembled into two groups of cells (upper and lower) that work together in parallel. This cell configuration has multiple benefits including increased efficiency due to lower resistive losses through the bus bars as each group of cells operates at the same voltage but half the current. The lower current also results in lower cell operating temperatures helps reduce the potential formation and severity of hot spots due to localised shading, dirt or cell damage. Additionally, since each group of cells is half the size, the busbar distance is reduced by half which means smaller busbars can be used resulting in less busbar shading losses and increased efficiency.

More recently, a number of manufacturers such as Trina Solar have started producing extra-large 210mm square cells which can be cut into three sections, known as 1/3-cut cells. These large format cells are used to produce high-powered panels up to 600W.

The Hanwha Q Cells Q.Peak Duo G6 panel uses half cut mono PERC cells with 6 round wire busbars

Half-cuts cell Improve shade tolerance

One of the greatest benefits of split-cell panels is when the are partially shaded. If the upper or lower section of the panel is shaded it does not affect the performance of the unshaded section. This is due to the two sections, or groups of cells, being connected in parallel and acting much like two small individual panels. During partial shading on the upper or lower section, the voltage is maintained and current is reduced by 50%, resulting in far better system performance when partially shaded.

Half-cut solar cells are used in split-cell panels to increase efficiency and improve performance in partially shaded conditions.

Shingled Cells

SunPower P series Shingled solar cell construction - Image credit Sunpower

Shingled cells are an emerging technology which use overlapping thin cell strips that can be assembled either horizontally or vertically across the panel. Shingled cell are made by laser cutting a normal full size cell in to 5 or 6 strips and layering them in a shingle configuration using rear side connection adhesive. The slight overlap of each cell strip hides a single busbar which interconnects the cell strips. This unique design covers more of the panel surface area as it doesn’t require front side busbar connections which partially shade the cell, thus increasing the panel efficiency much like IBC cells explained below.

Another benefit is that the long shingled cells are usually connected in parallel which greatly reduces the effects of shading with each long cell effectively working independently. Also, shingled cells are relatively cheap to manufacture so they can be a very cost-effective high-performance option, especially if partial shading is an issue.

Seraphim was one of the first manufacturers to release shingled cell modules with their high-performance Eclipse range of panels. The SunPower P series is the most cost-effective panel in the SunPower range designed primarily for large scale applications. Other well-known manufacturers producing shingled cell solar panels include Hyundai, Yingli Solar and ZNshine.

High-density Cells

To further boost panel efficiency manufacturers started introducing techniques to eliminate the vertical inter-cell gap between cells. Removing the standard vertical 2-3mm gaps between cells results in more of the total panel surface area being able to absorb sunlight and thus generate power which in turn increases total panel efficiency. This might sound like a relatively simple modification but the small gap provides space for the busbars to bend and interconnect the cells from the front side of one cell to the rear side of the adjacent cell.

Reduced cell gaps to increase cell density - Image credit Trina Solar

There are several techniques being developed to minimise or eliminate the intercell gap with the most common being to simply reduce the gap from around 2mm to 0.5mm as some space is still needed for the busbar interconnection. Traditional large ribbon busbars required several millimetres of space to bend between the front and rear of the cells. However, the transition to using much smaller multi-busbars has enabled the gap to be reduced significantly.

Increasing efficiency using Tiling Ribbon cell technology to remove the inter-cell gap - Image credit Jinko

To achieve this JinkoSolar developed what the company refers to as Tiling Ribbon or TR cells. Tiling Ribbon technology eliminates the inter-cell gap by slightly overlapping the cells and using a compression joining method. Tiling ribbon cells also dramatically reduces the amount of solder required which reduces the amount of silver needed making the panels both cheaper and more environmentally friendly.

IBC Cell Technology

The rear side of a Sunpower 'Maxeon' IBC cell showing the fine metal grid conductors which improves efficiency, helps reinforce the cell and prevents micro-cracking.

IBC or Interdigitated Back Contact cells have a grid of 30 or more conductors integrated into the rear side of the cell, unlike traditional cells which have 5 to 6 large visible ribbon busbars and multiple fingers on the front side of the cell. The most obvious problem with the more common front exposed busbar design is they partially shade the cell and reflect some of the light photons which reduces efficiency. IBC cells don't suffer this problem and as a bonus look much 'cleaner' with no exposed busbars.

IBC silicon cells are not only more efficient but much stronger than conventional cells as the rear layers reinforce the whole cell and help prevent micro-cracking which can eventually lead to failure. Sunpower uses a high-grade, solid copper IBC rear foundation layer on their patented 'Maxeon' cell design along with a highly reflective metal mirror-like surface to reflect any light which passes through back into the cell. The rear side of the 'Maxeon' IBC cell shown below is extremely tolerant to stress and bending, unlike conventional cells which are relatively brittle in comparison.

N-type Solar cell technology

While PERC and bifacial are the talk of the solar world the most efficient and reliable technology is still the N-type monocrystalline cell. The first type of solar cell developed in 1954 by Bell labs used an N-type doped silicon wafer, but over time the more cost-effective P-type silicon became the dominant cell type with over 80% of the global market in 2017 using P-type cells. With high volume and low cost being the main driving factor behind P-type it is expected that N-type will become more popular as the manufacturing costs reduce further and efficiency increases.

TOPCon solar cells

TOPCon stands for Tunnel Oxide Passivated Contact and is a more advanced N-type silicon cell architecture that helps reduce what is known as the recombination losses in the cell which in turn increases cell efficiency. Due to a complex number of factors, there are several losses within a solar cell that cause electrons to leak and recombine back into the silicon without forming an electric current. The ultra-thin TOPCon layer helps reduce this loss with a minimal cost increase to the production process. The TOPCon concept was first proposed by the German solar research institution Fraunhofer ISE back in 2014, but it wasn’t until 2019 that the technology was advanced enough to be deployed at scale and is now being used by several large manufacturers including Trina Solar, JA Solar and Longi Solar to achieve panel efficiencies above 22%.

Heterojunction - HJT cells

HJT solar cells use a base of common crystalline silicon with additional ultra thin-film layers of amorphous silicon on either side forming what is known as a heterojunction. The additional amorphous silicon layers reduce what is known as recombination at the N-P junction which essentially means it reduces loses and increases cell efficiency.

Panasonic created the efficient 'HIT' range of panels and was the leader in HJT cell technology for many years. REC group also recently released the Alpha series panels which use half-cut HJT cells combined with 16 micro busbars (16BB) to achieve an impressive 22.1% panel efficiency.

Panasonic HiT (HJT) cell construction - Image credit Panasonic Corporation

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The unique Panasonic HIT panels are available in Japan and North America; unfortunately, they are not available in Australia. Considering the high average temperatures in Australia, they would be a great choice for rooftops and large-scale commercial applications.

Improved high-temperature performance

The most impressive characteristic of HJT cells is the incredibly low-temperature coefficient which is around 40% lower compared to common multi and mono silicon crystalline cells. Solar panel power is rated under Standard Test Conditions (STC) which is measured at a cell temperature of 25°C. Every degree above the STC temperature reduces power output by a small percentage known as the power temperature coefficient. In common multi and mono-cells, the temperature coefficient is 0.38% to 0.42% per °C which can add up to reduce total output by up to 20% during very hot windless days. In comparison, HJT cells have a very low 0.26%/°C temperature coefficient.

It is worth noting that panel and cell temperature are also affected by roof type, and colour, tilt angle and wind speed, so mounting panels flat on a very dark rooftop will usually reduce panel performance compared to lighter coloured rooftops.

Diagram highlighting the increased high temperature performance and efficiency of heterojunction solar cells. — Diagram highlighting the increased high temperature performance and efficiency of heterojunction cells.

Latest Solar Panel Technology