PVTIME – In collaboration with Beijing Institute of Technology, Nankai University’s College of Chemistry has set a new efficiency record for n-i-p perovskite solar cells. Their findings were published online in Nature on 30 April. Led by Professors Yuan Mingjian and Jiang Yuanzhi, alongside Researcher Xu Jian, the research team has resolved a key physical barrier that was limiting device performance, proposing an innovative gradient-doped electron transport layer design in the process.
The photovoltaic device, which has been certified internationally, achieved steady-state photoelectric conversion efficiency of 27.17% and reverse scan efficiency of 27.50%, setting a new standard for n-i-p perovskite technologies. Perovskite solar cells are regarded as a leading next-generation photovoltaic solution, offering high efficiency and scalable fabrication potential.
Previously, the efficiency of high-performance n-i-p devices was limited to around 26% due to non-radiative recombination losses from micro-nano textured substrates, and the underlying mechanisms were unclear. The team identified energy band mismatch and electron accumulation at the tin oxide (SnO₂) and perovskite interface as the core cause.
Through detailed analysis of the chemical bath deposition (CBD) process used to fabricate the SnO₂, the team established the relationships between the structure, activity and composition of the ligand, the oxygen vacancy content and the energy bands of the thin film. They developed a ligand competitive binding strategy to create an n⁺/n continuously gradient-doped SnO₂ electron transport layer, thereby resolving dual interface challenges and minimising recombination losses.
The device achieved an open-circuit voltage loss of just 295 millivolts, confirming the effective suppression of non-radiative recombination. This breakthrough clarifies the long-standing performance limitations of n-i-p devices and provides a universal design pathway for metal oxide electron transport layers, thereby supporting the development of stable and scalable perovskite modules.
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