Efficiency - Page 8

Oxford PV has announced a record-setting 26.9% efficiency for its double-glass, 60-cell “residential sized” perovskite tandem module at the Intersolar Europe 2024 event. The module reportedly has a surface area of a little over 1.6 m square meters (1m x 1.7m) and weighs a little under 25 kg, “the ideal size for residential applications,” according to Oxford PV.

Oxford PV produces the proprietary high efficiency tandem solar cells at its manufacturing facility in Brandenburg an der Havel, Germany, and uses both in-house and contract services for the module assembly.

Reports suggest that LONGi has announced that it has reached 34.6% efficiency for a perovskite-silicon tandem solar cell, at the SNEC tradeshow in Shanghai, China.

The European Solar Test Installation (ESTI) reportedly certified the results, which represent a world record for this cell type. The previous record was held by LONGi itself, which achieved an efficiency of 33.9% in November 2023.

Researchers in China, led by Nanjing University, have designed a tandem perovskite-silicon solar cell with a top perovskite device based on an absorber treated with n-butanol (nBA), which reportedly reduces the detrimental effects of moisture in manufacturing processes carried out in air environment. The resulting PV device is said to have improved charge collection.

The nBA used by the team is a clear, colorless alcohol used as a cleaning agent in many industries, including electronics manufacturing. The team explained that it offers low polarity and saturation vapor pressure and ensures that the typical detrimental effects of moisture in perovskite cell fabrication in an ambient environment can be significantly reduced.

Researchers from Australia's Griffith University and Queensland University of Technology have reported the fabrication of planar carbon-based perovskite solar cells (c-PSCs) with high efficiency and excellent stability, by employing electrochemically produced large-area phosphorene flakes as a hole-transporting layer (HTL). 

Carbon-based perovskite solar cells have attracted increasing attention due to their many advantages, including: ease of fabrication, the potential of assembling flexible devices, low manufacturing costs and more. However, c-PSCs suffer from limited hole extraction and high charge carrier recombination due to inadequate interface contact between the carbon electrode and perovskite film.

Researchers from the University of North Carolina at Chapel Hill, Colorado School of Mines, National Renewable Energy Laboratory (NREL), University of Toledo and University of California San Diego have pointed out that the light-emitting diodes (LEDs) used in indoor testing of perovskite solar cells do not expose them to the levels of ultraviolet (UV) radiation that they would encounter in actual outdoor use. 

The scientists reported degradation mechanisms of p-i-n–structured perovskite solar cells under unfiltered sunlight and with LEDs. Weak chemical bonding between perovskites and polymer hole-transporting materials (HTMs) and transparent conducting oxides (TCOs) reportedly dominate the accelerated A-site cation migration, rather than direct degradation of HTMs.

Researchers from the Ningbo Institute of Materials Technology and Engineering at the Chinese Academy of Sciences recently reported a novel perovskite/silicon tandem solar cell based on flexible ultrathin silicon, with a thickness of about 30 µm.

Despite major progress in the efficiency of rigid perovskite/silicon tandem solar cells, flexible perovskite/silicon tandem solar cells have remained elusive. The team explains that this is due to the challenge of enhancing light absorption in ultrathin silicon bottom cells while maintaining their mechanical flexibility.

Researchers at China's Hangzhou Dianzi University have modified the absorber of a conventional perovskite solar cell with potassium trifluoromethanesulfonate (KTFS) and found that the additive improved the device's performance and stability. The cell’s perovskite film reportedly showed less lead defects and lower J-V hysteresis.

“The KTFS molecule is a typical kind of potassium salt including the cationic potassium (K⁺) and anionic trifluoromethanesulfonate (SO3CF3−), indicating a bifunctional interaction between KTFS and perovskite,” the team explained. “The sulfonyl group can passivate the undercoordinated lead of the deep-level defect and thus inhibit the non-radiative recombination.”

Researchers at CHOSE (Centre for Hybrid and Organic Solar Energy) at University of Rome ‘‘Tor Vergata’’ and Solertix (affiliated with Italy-based solar manufacturer FuturaSun) have reported reduced yield losses in cell-to-module scaling by utilizing ultranarrow interconnection of 19.5 μm. 

In addition, the proposed interconnection technique may be used to achieve a 30% efficiency in area-matched 4T tandem designs featuring a perovskite module over a silicon cell.

China-based global PV and ESS supplier, Jinko Solar, has announced a significant breakthrough in the development of its N-type TOPCon-based perovskite tandem solar cell.

Tested by the Shanghai Institute of Microsystem and Information Technology, the cell reportedly achieved an impressive conversion efficiency of 33.24%. This enhancement surpasses JinkoSolar's previous record of 32.33% for the same type of tandem cells.

Researchers at the Chinese Academy of Sciences (CAS), in collaboration with Japan's Yamagata University, developed three isomeric bisphosphonate-anchored self-assembled molecules (SAMs) to achieve highly efficient and stable inverted perovskite solar cells (PSCs).

The wettability, absorbability and compactness of SAMs, which are used as hole-transporting layers (HTLs) for PSCs, critically affect the efficiency and stability of the devices. Therefore, the researchers proposed a molecular strategy to synthesize three bisphosphonate-anchored indolocarbazole (IDCz)-derived SAMs, namely IDCz-1, IDCz-2, and IDCz-3. The three SAMs with different positions of the two nitrogen atoms in the IDCz unit were each employed on conductive oxide substrates for inverted PSCs.