Key takeaways:
Silicon PV is nearing practical limits, with future gains shifting toward cost, materials, and reliability improvements
Indian HJT research has progressed significantly, with lab efficiencies improving from 13% to over 23% in almost a decade
Policy frameworks and skill development remain critical challenges for scaling India’s PV manufacturing ecosystem
Perovskite development is advancing alongside improvements in packaging and stability for practical applications
Perovskite-HJT tandem technology shows strong efficiency potential but still faces long-term reliability challenges
The second edition of the TaiyangNews Solar Technology Conference India (STC.I) 2026 was held on February 5-6 in New Delhi. Following the success of STC.I 2025, the 2026 edition not only focused on technology and the Indian manufacturing landscape, but also on quality, market, and sustainability aspects.
The first session on Day 2 focused on Solar Cell Research Status & Outlook, with Asian and European institutes presenting on the current state of PV technology, the evolution of R&D, and the progress made over the past years. The talks mainly centered around the evolution of current technologies and how the industry is expected to take the next major step towards perovskites and perovskite-silicon tandem technologies, with Radovan Kopecek from ISC Konstanz discussing the limits and future outlook of crystalline silicon PV. Vamsi Komarala from IIT Delhi presented advancements in HJT research; Jai Prakash from NISE outlined India’s manufacturing and policy landscape; and Dinesh Kabra from IIT Bombay shared progress in perovskite and tandem development. Finally, Selvaraj Venkataraj from SERIS highlighted the status and potential of perovskite-HJT tandem technologies.
Providing a background on the progress made in silicon PV and the areas that need improvement, Radovan Kopecek, Co-founder and Director of ISC Konstanz, outlined the future trajectory and practical limits of crystalline silicon PV.
Radovan opened by stating that there is still significant scope for silicon PV. As module efficiencies approach 26%, which he considers the practical limit, there is still some room for improvement for crystalline Si-PV. He highlighted that cost reduction, silver consumption optimization, improved reliability, and recycling are some of the important aspects today. At the same time, PV remains the most cost-competitive energy source, with utility-scale LCOE expected to approach 1 ct/kWh soon.
From a regional standpoint, different markets are evolving along distinct technology paths. The United States remains a PERC-driven market because of the technology’s maturity, cost advantage, and ease of capacity ramp-up, while TOPCon is also constrained by patent limitations in US manufacturing. In parallel, companies like Corning are expanding their role in the PV value chain. With existing 7 GW of ingot and wafer manufacturing capacity, Corning is eyeing cell manufacturing in the US, as well as module assembly through its acquisition of JA Solar’s production lines.
India, in contrast, is rapidly scaling TOPCon capacity, with several expansion announcements in Q4 2025. In China, the focus is shifting to back contact (BC). With strict restrictions on new capacity additions, the Chinese manufacturing industry is looking to upgrade the existing TOPCon lines to BC.
Kopecek laid out practical limits to efficiencies and price for crystalline silicon PV. He indicated that cell efficiencies could reach 28% at approximately 4 ct/Wp, while module efficiencies approach 26% at 8 ct/Wp. At the system level, this translates to an LCOE of around 1 ct/kWh at utility scale. And together with battery storage, the LCOE would be around 1.5-2 ct/kWh, which is pretty promising.
BC efficiencies currently lead the market by about 1 percentage point over TOPCon. Even with all the improvements made to increase the current TOPCon efficiency (around 24% at the module level), the 1% absolute efficiency delta gap is expected to persist. At the same time, advancements such as LECO have played an important role in enhancing TOPCon’s competitiveness.
Looking ahead, tandem technology is expected to be the next shift, despite the technical challenges it currently poses. According to ITRPV, it is projected to hold about 10% of the global market share by 2035. TOPCon is expected to remain the dominant technology with about 45% share, and BC with 30%. However, Kopecek believes BC will reach this market share sooner.
Finally, he emphasized the importance of quality in manufacturing, and together with Fraunhofer CSP, ISC Konstanz can help manufacturers improve production stability and module reliability.
Vamsi Komarala, Renewable Energy Chair Professor at IIT Delhi spoke about the advantages of heterojunction technology and the progress achieved at the institute.
He highlighted the HJT fabrication process in 4 steps: silicon surface preparation, intrinsic and doped a-Si deposition in PECVD, ITO sputtering, and metallization. With an advanced PECVD tool compared to the previous one, IIT Delhi is now capable of depositing passivation layers on 6 square-inch wafers without any operational or performance uncertainties. To achieve this, the dissociation of SiH4 was studied, and the deposition of nanocrystalline doped a-Si was developed.
Carrier recombination and the effect of boron doping were studied to improve the efficiency of HJT. Surface, intrinsic, and doped-layer optimizations initially improved the efficiency from 13% to 20%. Further improvements, such as using a lower-resistive wafer, increased efficiency to 23% with a fill factor of 82% on a 4 cm² cell.
Komarala noted that research on developing thin HJT cells is also ongoing, with a resulting Voc of 747.33 mV achieved on a small lab-scale cell.
Jai Prakash, Deputy Director General at the National Institute of Solar Energy (NISE), began his discussion by providing an overview of India’s solar cell manufacturing capacity and its trends over the past decade. He also projected what the manufacturing capacity under PLI and non-PLI would look like in 2030.
As of December 2025, India’s cell manufacturing capacity stands at around 28.6 GW, increased from about 1 GW in 2014. Of the total, 4.2 GW qualifies under the Production Linked Incentive (PLI) scheme. This is projected to increase to 48 GW in 2030, with a total manufacturing capacity of 100 GW. The current total manufacturing capacity accounts for all technologies, including the 3.4 GW CdTe cell capacity.
Efficiency for mass-produced PERC cells in India averages 23.2%, while that of TOPCon is at 24.9%. It is noteworthy that the major share of capacity as of December 2025 is still PERC, totaling 14.17 GW. However, the latest expansion announcements and the ongoing ramp-ups are only for TOPCon.
According to NISE, the phase-out of PERC in India is some way off, as significant capacity remains. As such, the 20% minimum efficiency requirement for ALMM will likely remain in effect until 2026, increase to 21% in 2027, and reach 21.5% in 2028. From June 2026, with the new ALMM for cell enlistment, modules will be listed as adhering to ALMM requirements only if cells also pass the ALMM criteria.
Prakash also touched upon the PLI scheme, stating that about 4.2 GW of PLI module manufacturing capacity is currently operational, from Tata Power Solar, with more capacity set to come online in 2027. Under PLI, if a module achieves higher efficiency than the benchmark, additional incentives can be availed. He added that this is also one of the reasons for the rapid transition from PERC to TOPCon.
Prakash listed the challenges for manufacturing in India, starting with the unavailability of technology and tools for mass production and the dependence on imports. Process optimization and capacity utilization are another set of challenges. Access to skilled labor in both manufacturing and R&D is a major concern, hindering the technological competitiveness that India should be seeing. According to Prakash, headcount cannot be considered manpower, highlighting the lack of training and skilled personnel in the industry. Together with NSEFI, NISE is working to identify requirements and solutions in this area.
He also highlighted that the Ministry of New and Renewable Energy (MNRE) has a dedicated R&D wing that will support advanced technology research. NISE also started a 2.5-month course on Cell and Module Manufacturing in September 2025 to address the lack of skilled professionals in these areas.
Recent progress in perovskite cell research and its role in enabling tandem technology manufacturing was the main topic of discussion for Dinesh Kabra, Professor at IIT Bombay.
He highlighted the advancements over the last year, specifically the move from a 4 cm² substrate to a 9 cm² substrate, with an active area of 5.2 cm² in a 4T configuration. Kabra likened the research on advanced materials to the work on silicon that has brought it to where it is now. He emphasized that similar research is underway on perovskite, and it will get there too, says Kabra. An inherent advantage of perovskites is their high absorption due to their direct band gap, unlike Si, which has an indirect band gap and has limited absorption in the spectrum.
At the device level, IIT Bombay achieved an efficiency of 19.8% for a perovskite cell on a 9 cm² substrate. The team also developed a 4T tandem cell with a perovskite top cell on a silicon bottom cell, achieving 30.20% efficiency. The cells were packaged into a module for stability tests, with no degradation observed under 1,000 DH test conditions.
Kabra touched on global perovskite developments, noting that some Chinese players have commissioned PV plants using perovskite panels. These companies have their modules tested under IEC 61215 and have passed the standard panel stability assessments.
On the sustainability side, perovskite also has an advantage, as it contains only about 0.5-1 g/m2 of lead (Utmolight’s perovskite panel), while the commercial silicon module of 2.8 m2 area has 4 g of lead in its solder. Additionally, the CO2 emissions associated with perovskite modules as measured by Microquanta, is about 150 g/W, while it measures about 400 g/W for a crystalline silicon PV module.
Concluding with a roadmap for the team at IIT Bombay, Kabra stated that development for space-grade PV using perovskite-silicon tandem technology is underway. Large-area tandem cells are being built, with an efficiency target of over 30% to be achieved in 24-30 months. Finally, plans are in place to set up a 20 MW R&D line within 36 months.
Selvaraj Venkataraj, Senior Scientist at Solar Energy Research Institute of Singapore (SERIS), presented an outlook on the progress in perovskite-on-HJT tandem technology.
SERIS, a pioneer of floating PV, also offers services such as cell and module characterization and reliability testing. Venkataraj highlights the need for high-efficiency technology adaptations for the manufacturers to survive the low module prices, which currently average around 10 ct/Wp. Therefore, perovskite-silicon tandem technology is the way to go for higher efficiency.
SERIS has lab equipment compatible with industrial-level cell and module processing, capable of processing large-area silicon cells up to 200 cm².
Venkataraj rooted for perovskite tandem technology because of its high-efficiency capability, which has a significant impact on reducing LCOE. However, he also stated that the module must perform at the same level throughout its operational lifetime, which is a major challenge with perovskites.
Using an in-house silicon cell as the bottom cell, SERIS has achieved 33.2% efficiency on a 1 cm² perovskite-silicon tandem cell. On a large area of 16 cm², it achieved an efficiency of 28.2%. Recently, it achieved 24% efficiency in perovskite-tandem cells on a 244 cm² area, with a target of 28% by the end of 2026. The bottom cell in all these tandems is HJT-based. On a TOPCon-based bottom cell, SERIS achieved 23% efficiency on a 16 cm² cell. Venkataraj claims that the company achieved a world-record efficiency of 27.5% with a 3T perovskite-perovskite-silicon tandem cell on a 1 cm² area.
He indicated that SERIS is also making modules with single tandem cells for further study. Outdoor tests performed on mini-modules with an edge sealant demonstrated durability for more than 5 months without moisture ingress.