Chinese researchers achieve world-record efficiency of 27.17% for inverted perovskite solar cell

<p class="p1"><span class="s1">The proposed inverted perovskite solar cell design reduces band misalignment and electron accumulation, suppressing recombination losses and enabling high efficiency in both small-area devices and scalable modules.</span></p><p>Researchers from <a href="https://www.pv-magazine.com/2026/04/27/chinese-scientists-build-silver-free-heterojunction-solar-cell-with-25-2-efficiency/" rel="noopener" target="_blank">Nankai University</a> and <span class="hover:entity-accent entity-underline inline cursor-pointer align-baseline"><span class="whitespace-normal">Beijing Institute of Technology </span></span>in China claim to have achieved a world record power conversion efficiency for a perovskite solar cell with an inverted architecture.</p>
<p>Inverted perovskite cells have a device structure known as “<a href="https://www.pv-magazine.com/2018/06/22/researchers-turn-to-spray-coating-in-applying-etl-to-perovskites/" rel="noopener noreferrer" target="_blank">p-i-n</a>”, in which hole-selective contact p is at the bottom of intrinsic perovskite layer i with electron transport layer n at the top. Conventional halide perovskite cells have the same structure but reversed – a “<a href="https://www.pv-magazine.com/2019/11/22/scientists-hit-21-6-perovskite-cell-efficiency-using-concentrator-pv/" rel="noopener noreferrer" target="_blank">n-i-p</a>” layout. In n-i-p architecture, the solar cell is illuminated through the electron-transport layer (ETL) side; in the p-i-n structure, it is illuminated through the hole‐transport layer (HTL) surface.</p>
<p>Although inverted perovskite solar cells have shown rapid efficiency gains in recent years, these devices still lag behind n-i-p counterparts, due to persistent non-radiative recombination losses occurring at the textured interface between the ETL and the perovskite absorber. &#8220;Previous reseach had struggled to identify the physical mechanisms driving these losses,&#8221; the research team explained. &#8220;With our work, we showed that energy-band misalignment and electron accumulation at the buried interface act together to accelerate carrier trapping and interfacial recombination, ultimately limiting device efficiency.&#8221;</p>
<p>The scientists investigated, in particular, the interaction between an ETL made of tin oxide (SnO₂) and the perovskite interface. They found that lattice mismatch and electron accumulation jointly increase non-radiative recombination, reducing cell efficiency.</p>
<p>The group then examined the growth mechanism of chemically bath-deposited SnO₂ films and established links between ligand chemistry, oxygen vacancy concentration, and the material’s energy band structure. Based on these findings, they developed a “ligand competition and combination control” strategy to fabricate a continuously gradient-doped SnO₂ ETL featuring a transition from a lightly doped region to a heavily doped region.</p>
<p>&#8220;This graded architecture simultaneously minimizes band offset and accelerates electron extraction, thereby effectively suppressing the cross-interface recombination,&#8221; the academics explained, noting that the proposed cell structure successfully transitions from a lightly doped n-region near the perovskite interface to a heavily doped region farther away, helping to reduce interfacial mismatch and electron accumulation simultaneously.</p>
<p>Tested under standard illumination conditions, the solar cell achieved a certified power conversion efficiency of 27.17%, setting a new efficiency record for the inverted device architecture. The device also delivered a reverse-scan efficiency of 27.50%, meaning it reached an even higher efficiency when the current–voltage measurement was performed by scanning from high voltage to low voltage. Researchers often report both forward- and reverse-scan values for perovskite solar cells because the technology can exhibit hysteresis, where measured performance varies depending on the scan direction and measurement conditions.</p>
<p>The researchers also achieved a power conversion efficiency of 25.79% for a 1 cm² single-junction device, indicating that the interfacial engineering approach remains highly effective at the laboratory scale. They also fabricated a larger perovskite module with a 16.02 cm² aperture area, which delivered an efficiency of 23.33%.</p>
<p>&#8220;Our research has dispelled the longstanding &#8216;performance fog' surrounding formal structural devices at the mechanistic level, opening a universal and effective new pathway for the rational design of electron transport layers in inverted perovskite devices,&#8221; the academics concluded. &#8220;This development is expected to provide technical support for the high stability and scalable production of perovskite photovoltaic modules.&#8221;</p>
<p>The new solar cell design was presented in &#8220;<a href="https://www.nature.com/articles/s41586-026-10587-4" rel="noopener" target="_blank">Continuously graded-doped SnO₂ for efficient n–i–p perovskite solar cells</a>,&#8221; published in<em> nature.</em></p>